How to choose a lens: from complex to simple and vice versa. What types of lenses are there and how do they differ from each other?
03.12.2011 26083 reference Information 0
The modern camera has undergone very few changes compared to those large-format machines that the world saw in the form of the creations of Niepce or Prokudin-Gorsky. Yes, they became smaller, got autofocus, image stabilization, and then the photographic plate was replaced by film, which itself became a victim of the digital matrix... but globally nothing has changed: the image on the photosensitive material continues to be projected using the lens, which has always been the main factor in creating the image .
Cool photographers have the opportunity to try everything, but, naturally, they shoot with the lenses they like most - and for some reason they usually like rather expensive optical devices. Enthusiasts have been collecting lenses for years, clinging to one system, changing some items in the collection from year to year for a number of reasons... however, all these are people who already know the taste of photography. What should a beginner do?
Indeed, when buying a camera, a person is rarely guided by his own sanity and does not understand the words “wide-angle” and “long-focus”, but he perfectly buys into “zoom”, sincerely believing that the larger it is, the better the lens. Meanwhile, the situation is rather the opposite - however, it all depends on what to put at the forefront. From the point of view of versatility, a high-power zoom is indeed better, but for quality the situation is the opposite - a larger zoom leads to greater optical distortion.
Focal length
First, a little theory... The most common camera system in the world is based on 35mm film ("Type 135"), which is exactly the Kodak you shot with back in the days of film cameras. It is this standard that has therefore become a guideline for photo manufacturers in the consumer sector, and it is this that we will talk about in the article below, “forgetting” that there is also a medium and large format.
Today's lenses, one way or another, are tied to the 35 mm format, despite the fact that cameras today are farther from it than ever - less than 1% of all cameras that are oriented to this standard are produced for a similar frame size (24x36 mm) . Moreover, the vast majority of cameras produced (more than 90%) are compact ones, in which the size of the light-sensitive matrix is 4-6 times smaller than the area of the same film frame. And yet, in order to follow at least some standard, 35 mm film became the reference point for everyone.
If you look at the lens of a compact camera, you can often see two scales on it, for example 8-24 mm f/2.8-5.0 (38-114 mm), where the designation in brackets corresponds to the focal length (note, this is not the lens size), recalculated in 35mm equivalent. This is precisely why lenses differ (all other parameters are not as important as they say).
To understand this, let's imagine two cameras: an old film point-and-shoot camera and a modern digital compact with a resolution of 10 megapixels. We shoot the same frame on both at 38mm from the same position and print it on 10x15. Having looked at the frame and not paying attention to the difference in quality, we understand that there are practically no differences in the space covered - and therefore, is there any difference for us that the matrix is 4 times smaller than a film frame, but in fact the focal length is only 8 mm ? That is why the focal length (FL) is simply multiplied by the corresponding coefficient (“crop factor”), which can be obtained by dividing the size of the film frame diagonally by the corresponding size of the matrix - this is how the effective focal length is obtained.
However, for DSLRs the situation is the opposite: sincerely believing that their owners are extremely experienced people and understand the essence of the issue, none of the manufacturers of lenses for DSLRs bothers to calculate the EGF for them. Meanwhile, there are not so many full-frame cameras - mostly professional models, of which no more than a dozen have been produced by all manufacturers today - and the overwhelming majority of DSLRs existing today have a matrix 1.5 times smaller in size, for which a lot of lenses have already been released that do not support full-frame coverage . However, the indication of focal lengths even on them remains standard for “mirror” lenses - the user simply needs to multiply the focal length by the corresponding crop factor (×1.5) in each case. By the way, if you crop a photo in the editor, you also change the EGF (if this is interesting, of course) - after all, you print the photo on paper of the same size or watch it online at the same monitor resolution... For example, if you shot a frame at 50 mm, multiply by 1.5 (crop factor), crop, for example, by 30% and, accordingly, multiply by another 1.33 - it turns out 100 mm.
We hope this is all clear, so further we will talk about the effective focal length, and for SLRs we will indicate both numbers - this will be more convenient for everyone, and it does not matter what you shoot with. It’s just that in a DSLR you can always choose the appropriate lens, but for a compact it will be quite difficult to set the appropriate focal length - so do it at random. However, the article is addressed specifically to beginner “mirror-makers.”
What are lenses for?
Let's arrange the lenses in a table, from the minimum focal length to infinity, and describe their main characteristics and purpose (conditionally, of course):
Now let’s take a closer look at why we need each type of lens separately - this will help us decide whether it’s worth buying them and for what purpose.
Fisheye, ultra-wide-angle lens
Fish-eye lenses are characterized by a very wide angle of coverage of the surrounding space - with a standard 180° diagonal of a cropped frame, they simply have no competitors. The record holder in this direction is Sigma, which released a lens with a focal length of 4.5 mm and a relative aperture of 2.8 - naturally, it costs fabulously, but it also produces a picture that covers more than 180°.
However, for such a wide coverage angle (almost everything that our eyes can see without moving, along with peripheral vision) one has to pay a good price. No, we don’t mean that fabulous money for the Sigma we mentioned, everything is much simpler: due to the ultra-wide coverage, the optical distortion of the lens becomes almost the same as the bend of its front lens - it’s not for nothing that it was called a “fish-eye” (apparently the inventors were aware of the peculiarities of fish morphology). However, photographers did not suffer from this for long, having learned to use these weaknesses to their advantage - the lens perfectly distorts perspective and has an almost infinite depth of field from half a meter already at aperture 5.6, i.e. you can film a person from a level of 20 cm above his head, and the head in the frame will be huge, and the legs will remind us of dwarfs. It also interestingly distorts linear objects - the columns on the sides of the frame bend outward, only the circles remain circles (at worst, ellipses), but all other objects “float”.
In general, the lens is considered more of a good entertainment device (almost 100% of cases of its use are for experiments) than a serious tool - which is true, even in a cramped room a person will not like to be arched at the edges of the frame, even along with columns.
Wide angle lens
“Shirik” is a necessary tool for landscape photographers and reporters who photograph intimate corporate events or parties. EGFs here start from 15-16 mm (the example shows Tokina 12-24, which is 18-36 mm), allowing you to cover 90° and even a little more, which is enough for shooting even in a room. It is usually stated that a “big hole” of 2.8 is completely unnecessary for a wide one - however, corporate professionals are unlikely to agree with this, who often have to work only in pitch darkness, and you can meet all kinds of people here, including those who are afraid of daylight , with which they may confuse the flash pulse.
The advantage of a regular linear wide-angle over a fisheye is that the image is almost distortion-free (the higher the price, the less spherical distortion and the larger the relative aperture), but the disadvantage is that the coverage angle is almost half as large.
The lens can also be used to distort the proportions of objects - when shooting objects from an angle, close up, it visually “compresses” them (if you have seen a 16:9 picture shown on a 4:3 TV, you will understand), since the eye perceives the picture as normal (shot with a “normal” lens), and it is wide-angle. However, this effect also occurs in some computer games.
Note that people standing at the edges of the horizontal frame become noticeably fatter and only lose weight as they approach the center of the frame.
Normal lens
In film times, a “normal” (standard) lens was considered a “fifty-kopeck” lens, but with the advent of times of smaller matrices (after all, a full frame is now too expensive for an enthusiast), it was replaced by a 35-mm lens, although many continue to use fifty-kopeck lenses, even though their coverage angle has been reduced completely to a moderate portraiture.
There is little that is normal in the lens - if we exclude human peripheral vision, a 50 mm lens gives exactly the same picture that a person sees, and therefore all proportions are respected (wide-angle lenses differ in this - they simply capture part of the field from peripheral vision). Actually, before this was enough - then it was just “zooming with your feet.” Today it has been replaced by a real zoom.
In essence, of course, there is nothing to replace fifty dollars with - this is the very line between a wide-angle and a long-focus lens on which more than one generation of successful photographers has grown up. Usually they make it quite fast, about f/1.8, and for ridiculous money, about 100 bucks, which many people buy - however, when everyone around is with zooms, the lens still loses in terms of versatility, but it quickly teaches the photographer how to play within the frame. In other words, lenses of this type are more for training than for everyday use in different situations - the angle is insufficient for indoors, and you won’t be able to take a normal portrait.
Universal lens, kit
When buying your first DSLR, be sure to take it complete with a “kit” - manufacturers are making a cunning move aimed at selling their own, “original” glass, reducing the price of a standard lens below its market value (i.e., if you buy such a lens new separately from the camera, the total difference will be 100-200 dollars, which can be spent on just fifty dollars). The quality of the staff is not so great, but you will see this only after a year or two of shooting, and only then if you are lucky - and by then, perhaps, its plastic body will not begin to serve as well as in the old days.
In fact, functionally standard zooms have replaced standard fifty-kopeck lenses - the 50 mm EGF today is in the middle of their range (in the case of 18-55, of course). It turns out that that same fifty-kopeck piece was simply expanded with the possibility of zoom, and that’s all, leaving the fifty-kopeck piece itself. Do you see the number 35? This is him.
The advantage of the “whale” over the “fifty kopeck” is in functional terms, since it allows you to photograph the situation in the room, and good portraits come out of it, you just need to twist the zoom ring. The disadvantages are also obvious - it always loses in quality, however, this can be safely discounted at the beginning of a creative journey, since you cannot find a better lens for studying.
Portrait lens
Don't look for a portrait type inscription on this lens - there are none. A portrait lens simply has an EGF focal length of 85-120 mm, depending on the taste of the photographer. The reason is simple: when communicating with a person, most of us look at the interlocutor with both eyes, and therefore we are accustomed to seeing a very specific angle, and only people with one-sided visual impairments see opponents differently - however, no one has ever taken the minority into account, and cynics photographers are no exception. To understand these people without changing your position, close one eye with your hand and see how much the perspective has changed: the cheekbones have widened, the ears have hidden, the nose has spread... do you like it? And the reason is simple: looking with two eyes, the light from an object (naturally reflected - few people glow in person during life) spreads in one direction, practically without converging, and with one we force it to converge at one point at an angle. The situation can be corrected by making this angle sharper so that the outer rays are closer to parallel lines, which is what we have when looking at an object with two eyes - not a fountain, of course, but this is the best of what we have... after all, the lens has only one organ of vision.
Naturally, portraits are taken from a certain distance (remember the “zoom with your feet” again), depending on what is needed: close-up, chest, waist or full-length - the narrow angle of coverage of the lens itself will “bring us closer” to the object.
Please note that there are a bunch of different portrait lenses - macro lenses are similar in their technical characteristics, but the requirements in both cases are different: a “portrait lens” should not only give a sharp image in the focus area, it should also blur the background beautifully (if you know what “bokeh” is, you will understand), while from “makrik” only sharpness is required.
Macro lens
Macro photography is almost the only direction in photography where everything or almost everything depends on the technique used for shooting. Of course, artistic flair is important here, but a good lens will do its job much better for you - which is why many beginners start with macro. A macro lens is any lens labeled “macro” or “micro,” which not only makes it stand out as a cool kid, but simply allows it to focus closer. If you look at the table of lens characteristics, you will see the “minimum focusing distance” parameter, which for modern lenses can be 35-38 cm, and for macro lenses - 5 cm or less. Naturally, whatever the lens, the same is how it works in macro - if you don’t want to do a lot of shamanism in Photoshop to fine-tune the results, buy a good one right away, although you probably shouldn’t make macro gaming a lifelong hobby either.
Of course, it’s good to have a fast focusing motor, but this is not at all necessary - you won’t be able to catch a bee on the fly even with fast autofocus, and you need to use prefocus and its locking function in conjunction with burst shooting. But the open aperture plays a double role here: the “big hole” allows you to shoot in poor lighting, but does not provide the desired depth of field required for macro, so you still need to clamp the hole. However, in some cases, ultra-small depth of field, characteristic of macro, gives good results. Please note that the most budget lens models (like the one in the photo) “clutter” the picture, i.e. It doesn’t provide the clarity for which macro is valued - yes, this can be compensated for in the editor, but it won’t be the same.
In theory, a macro lens, like a portrait lens, simply does not have the right to be universal - both have very narrow applications and, as a result, have design and quality features, and therefore should be purchased only for these purposes. Naturally, it’s bad manners to shoot portraits with a macro lens, but if there is no other lens, who will forbid it? Personally, I didn’t specifically buy a makrushnik for myself—I just used the one I got from the film era.
Long lens, telephoto lens
A lens that often allows you to “get closer” without actually doing so - as a rule, such lenses themselves are longer than all the ones we talked about above. These are the ones that photographers often measure against, although it would seem there is no point - well, you take a picture of a bird in the sky or the moon there, and then you go to any hosting and upload it there, providing it with the appropriate tags, but then, sorting by these tags, you will get a couple more thousands of similar frames from other users, and the ego will suffer greatly. Yes, reporters will not agree with us - they are fed with such lenses (not the same as in the photo, but longer and thicker - it is in their work that size matters), because getting closer to the president and puffing a powerful strobe into his forehead makes it far away not everyone.
However, no one bothers you to buy this toy - after all, there are things that you need to get over yourself: chickenpox, puberty and male “measurements”. Even if you don’t get rid of it later, you will still be satisfied.
With this lens, as a rule, they photograph government officials, fashion shows, neighbors from the house opposite in negligee and without it :). Oh yes, also the moon and birds - after all, we see them so rarely in life.
Hood
It would seem that this is another useless thing in a photographer’s arsenal, since, on the one hand, it makes a completely non-compact camera even more non-compact, and cannot be removed quickly, despite the fact that it practically does not interfere with catching sunbeams (and that’s what it was made for, it would seem that). It can either simply be in the form of a small cylinder that screws into the mounting thread of the filter, or an advanced one, with a bayonet connection and on plastic lenses, with which many have dislodged the front moving part, trying to remove it from them, especially from new ones (the connection is strong, reliable and undeveloped, but your hands are not used to it yet) - in fact, this is an opportunity to earn extra money for workshops that repair optical devices and their manufacturers, who will be happy to sell new ones.
However, there is still a benefit from a lens hood: although it is inconvenient to put a lens cap on the lens with it, a lens hood can sometimes protect the lens from damage (when you forget to put it on), sometimes even from a low fall, or from children’s fingers. Moreover, it gives the lens the appearance of a more serious optical device and immediately identifies the photographer as a beginner, since most people who use the lens for more than a year or two have lost it, collecting dust on a shelf, or have a broken mount.
In many cases, it can be used on tours where tripods are often not taken - when you need to place something under the lens so that it does not fall down when installing the device on slippery rocks.
By the way, it is better to remove the hood when it is not in use and, turning it over, do not fix it on the lens, although there is such a possibility - you will lose efficiency, because. it tends to cover the zoom or manual focus ring, depending on the lens design.
5 biggest misconceptions that prevent you from making the right choice of lens
1. Aperture is better than image stabilizer
Let's figure out what the stub does and what the aperture does. Firstly, the stabilizer helps to obtain shutter speeds that are quite long by classical standards (rule 1: EGF), without blurring the picture. This feature is very useful in the tele-band. Secondly, lenses with a stub often have a special mode for shooting with wiring, i.e. The stabilizer only works on one axis. Thirdly, the stub works regardless of the selected aperture, and therefore does not affect the depth of field. Fourthly, the stub does not affect the subject in any way, and even if it helped to avoid blurring the whole thing, it is not able to prevent the sudden movement of the subject. The aperture allows light to pass through the lens faster and form an image faster. Moreover, the wider the aperture is open, the faster the image is formed, and the shallower the depth of field. An aperture that gives short shutter speeds helps, for example, to freeze an object in motion. But in general, to tell the truth, comparing a stub with aperture is the same as comparing skis and a snowboard. These are two different tools that can show their strengths depending on the specific task. It's convenient to have both tools available in one lens.
2. The cooler the lens, the more expensive it is.
Many modern budget lenses can compete with much more expensive ones in sharpness, but this is not the only parameter for a lens. Today, manufacturers pay a lot of attention to the functionality of lenses - they equip them with a stub, a large range of focal lengths, and dust and moisture protection. Moreover, in conditions of fierce competition, they often deliberately deteriorate the quality of the design and try to reduce the cost of the product by using cheaper materials. The presence of a plastic bayonet mount on a lens is not so uncommon today.
There are great lenses when it comes to optical quality, but when it comes to durability, they will end up at the bottom of the list. A very striking example of this is the Canon 50mm 1.8 Mark II. The image is simply amazing. They speak of it as a “hidden elka”, but the quality of this lens is not impressive - there is no focal length scale, there is a very cheap and noisy motor, there are only 5 aperture blades, the automation often blurs the focus, the bayonet mount is made of plastic, and so on, but at $100 it's a great lens that I think every Canon user should have.
When we buy a lens, we pay not for the pictures that we then shoot, but for the optical quality and workmanship + functionality. If we buy an expensive model, then all three parameters will be at a high level, but not necessarily at the highest level. If we buy a relatively inexpensive lens, we undoubtedly make a compromise. It could be anything - workmanship, functionality, optical quality, aperture ratio, focal length range, or even brand. Therefore, it is important to set your priorities and buy exactly what you need, while being the last to compromise on optical quality.
3. Native Canon and Nikon optics are much better than third-party brands Sigma, Tamron, Tokina
There are many examples where third-party optics turn out to be at least as good as native lenses. And to say that Sigma, Tamron, Tokina are garbage is simply stupid. It's all about the market positioning of specific brands. For example, Sigma, which in the past has earned a reputation as a relatively unreliable manufacturer, is focused on producing cheap zooms with low aperture and mainly for cropped cameras. Recently, the manufacturer has significantly improved quality control and expanded the range of its lenses. Now the assortment includes the Sigma 50mm F1.4 EX DG HSM and Sigma 85mm F1.4 EX DG HSM primes, which are excellent in both quality and design. The optical design of these lenses is in-house developed. Another manufacturer Tamron also pleases with the excellent quality of its top-line products. The company's pride is fast zooms with a constant relative aperture. The excellent Tamron 17-50 mm F2.8 XR and Tamron SP AF 28-75mm F/2.8 XR Di LD zoom lenses are a huge market success, and the Tamron SP AF 90mm f/2.8 Di macro prime is considered one of the best in its class . Tokina is much less known to a wide range of amateur photographers, but it is perhaps the only third-party manufacturer focused primarily on quality, and directly competes with the best lenses from Canon and Nikon. The only drawback I can name is the relatively small range of products. To be honest, it’s even a little insulting for a worthy brand that is so underestimated by the photographic community, although it produces “elite” level lenses.
4. Fix is better than zoom
No that's not true. Perhaps this could have been said once, but now it’s definitely not. Previously, the quality of zooms was much lower than it is now. Today, such excellent zooms are produced as Tokina AT-X 16-28 f/2.8 AF PRO, Tokina 50-135mm f/2.8 Pro DX AF, Nikon 14-24mm f/2.8G ED AF-S, Canon EF 70-200mm F2. 8 L IS II USM, which in their range produce a much better picture than many primes. It’s not for nothing that the best zooms are jokingly called “a set of primes.”
True, primes also have a number of advantages, for example, the same aperture ratio, weight, design, price. Zooms are more versatile and this versatility can be useful in certain conditions. There are situations when a large aperture ratio is needed, then it would be preferable to use a prime lens. There are also tasks where it is necessary to use an 800mm super telephoto lens, for example for wildlife photography. Then you can’t do without the Canon EF 800mm f/5.6 L IS USM prime, and not a single zoom can adequately replace it. The situation is similar with specialized macro lenses and tilt-shift lenses.
5. The more you clamp the aperture, the better the sharpness, and when it’s open it’s always blurry
This is the most common misconception among beginning photographers. Firstly, it’s not always soapy at an open aperture, and secondly, the main thing is that each lens has its own “sweet points”. For the vast majority of lenses, at the maximum aperture, the sharpness index drops significantly even in comparison with aperture 8. This is to blame a physical phenomenon such as diffraction (the phenomenon of light deviation from the rectilinear direction of propagation when passing near obstacles).
Most often, the peak sharpness of a lens appears when the aperture is closed by 2-3 stops. But this rule should be taken very conditionally, because there are a great many exceptions.
This chapter is intended primarily for those who have switched from a soap dish to a DSLR. The autofocus of a compact camera is quite easy to use - it almost always has a face detection function, which allows the photographer not to pay attention to choosing the focus point at all - the autofocus itself will aim where it is needed. Even if the autofocus of the point-and-shoot camera misses a little, it’s not scary - the depth of field is almost always quite large and objects come out clearly from 1.5 meters to infinity (of course, unless the autofocus mistakenly enters the macro zone, in which case everything will be blurred). The only task of an amateur photographer is to eliminate a serious autofocus mistake and voila - the photos turn out clear.
With a DSLR everything is not so simple. The depth of field is much shallower than that of a point-and-shoot camera, and only those objects that are autofocused on are “absolutely sharp.” Everything that is closer and everything further is blurred to one degree or another. However, thanks to the ability to control the depth of field in a device with a large matrix, it is possible to achieve a “point-and-shoot” effect, when everything is sharp - both the foreground and the background.
Another difficulty is caused by two completely different focusing modes - through the viewfinder and on the screen (liveview). As a rule, the instructions do not say which mode is best to use.
But that's not all! It is also advisable to understand such a function as choosing the focus point, since the automatic machine does not always correctly understand our idea and stubbornly focuses in the wrong place (for example, when shooting through glass, we want to focus at infinity, but the automatic machine stubbornly focuses the lens on the dust on the glass ).
So, let's consider in order all the issues related to the effective use of DSLR autofocus.
Which is better - LiveView or viewfinder?
The image enters the mirror viewfinder by being reflected from the mirror and passing through a pentaprism (some devices have a pentamirror), so the viewfinder allows the photographer to see “through the lens.” LiveView mode (live viewing) involves displaying the image on the camera’s LCD screen, that is, it displays what the matrix “sees”. There is no difference in photo quality, but each of these viewing modes has features that you should be aware of in order to get the most out of your camera.
When working in LiveView mode, shooting with a DSLR is no different from shooting with a point-and-shoot camera. At first glance, this is convenient and familiar, which is why a significant number of novice SLR photographers prefer this type of shooting. But in fact, LiveView has many more disadvantages than advantages. Let's try to list them...
I think these three reasons are enough to reconsider your attitude towards LiveView mode. However, if this mode is implemented, then it is still needed for something, right? When is using LiveView preferable to using a mirror viewfinder?
- Shooting from a tripod. LiveView mode is indispensable if the height of the tripod is greater or less than your height. If you use a mirror viewfinder, then in the first case you will have to stand on tiptoes to look into the viewfinder, in the second you will have to bend over backwards or even crawl on your stomach if you are shooting at a very low point. The same applies to shooting without a tripod, for example, holding the camera high above you (above the heads of the crowd) - in this case, shooting is done blindly and the percentage of defects is very high. Enabling LiveView will allow you to feel much more comfortable in this case and at least somehow see what is in the frame.
- Using manual focus. This is especially true when using non-autofocus optics, among which there are some very interesting glasses. Most amateur cameras have a relatively small reflex finder and manually aiming at it can be very problematic. LiveView has an excellent feature - enlarging the central fragment. This will allow you to focus manually the first time and with very high accuracy.
- Live histogram, rulers, exposure level. When using LiveView, very useful things can be displayed on the screen - a grid with which it is convenient to align the horizon line (some devices display a “level”), a histogram that allows you to avoid the appearance of overexposed and underexposed areas. You can read more about these things in the Photobook - chapter Exposure, shutter speed, aperture.
Some "pretentious" photographers believe that these functions are "for complete dummies" and do not recommend using them, because it allegedly "dulls the brain." Personally, I don’t agree with them; these functions can be very useful, since they allow you to get normal pictures the first time, and not the tenth. After all, what difference does it make to the viewer how a given frame was obtained?
If you try, you can remember some other advantages of LiveView over a mirror viewfinder, but it is clear that in some cases the LiveView mode can be very useful.
So, which is better to use - viewfinder or LiveView? In most cases it is better to use mirror viewfinder, since the speed of the camera is much higher and the power consumption is lower. If we are talking about leisurely shooting from a tripod, using non-autofocus optics, as well as shooting in difficult conditions (for example, against the sun), LiveView mode will make the filming process more comfortable and productive - mainly due to the fact that you will see the approximate result on the screen in advance and, if something happens, you will be able to make the necessary adjustments to the settings. You will have to pay for the convenience with increased power consumption and low autofocus speed.
Using the DSLR Viewfinder
So, we agreed that in everyday shooting we will use a mirror viewfinder in order to make the most of the speed capabilities of the DSLR. However, there is one thing that needs to be figured out, namely, how to configure the autofocus system to work as quickly and predictably as possible.
If you look into the viewfinder, you can see small squares on the focusing screen. They are located in the places where the focus sensors are located. By default, the camera's automation itself determines which sensors to focus on. The logic is simple - focus is focused on the nearest object that hits the focus sensor. What types of focus sensors are there?
The most accurate focusing sensors are placed in the center of the frame (cross-shaped, double cross-shaped), linear sensors occupy a place on the periphery of the frame.
For simplicity, we will use a small number of focus sensors. This arrangement of focus sensors was in the first inexpensive digital SLR Canon EOS 300D. Modern devices have much more focusing sensors, but the overall picture has not changed - there are cross-shaped sensors in the center, linear sensors on the periphery.
If the choice of autofocus sensor is left to the camera's automation, when focusing, all sensors are polled - both central and peripheral, and based on this data a decision is made - which object to focus on. This scheme almost always works correctly, but sometimes “controversial situations” arise. For example, if there are objects in the foreground and background that are equivalent from the point of view of the automation, the autofocus begins to “sweep” between them (in photo jargon, “crawling”), and this continues until the automation decides what to focus on. stop choosing. As luck would have it, autofocus likes to throw out such numbers at the most inopportune moment, which can infuriate the photographer :) How to deal with this?
It is logical to assume that if you force focus on only one sensor, autofocus will be much more predictable - it will aim at the object located under the selected sensor without hesitation. In any DSLR you can set the sensor that will be used to focus. Which sensor should you choose?
Opinions are divided on this issue. Some people prefer to choose a sensor depending on the location of the subject in the frame:
This approach is convenient when shooting from a tripod, when you first compose the frame, and then focus and shoot.
If you need to act quickly, it is inconvenient to choose the focus point each time, so many photographers act as follows - set the forced center point focusing(we remember that the central sensor is the fastest and most accurate), they fix the focus on the desired object by half-pressing the shutter button, and then compose the frame so that the object takes the desired position, in accordance, for example, with the rule of thirds. Let's look at a specific example...
Suppose we decided to photograph this landscape:
There is a rather dark object in the center of the frame that autofocus may not be able to focus on. But on the right, at exactly the same distance from us, there is a much more contrasting area, to which autofocus, no doubt, will be aimed very quickly.
What are we doing? Point the center point at a contrasting object and half-press the shutter button:
Autofocus quickly focused and gave us confirmation in the form of a sound signal and highlighting the focus point. Without releasing the button, we move the camera so that the composition matches our creative intent:
As long as we keep the shutter button half-pressed, autofocus is locked. After the frame is properly composed, press the button all the way. The shutter fires, the photo is ready!
The method described above is very convenient when shooting handheld and is very quickly brought to full automaticity by the amateur photographer - we point at the desired object, make a half-press, compose the frame as needed, press the button. Plus, this method is the fastest and most accurate.
Despite all its advantages, center point focusing has a number of limitations. They most often appear when shooting at very close distances with a shallow depth of field. Let's say we take a close-up shot of a flower. We placed it in the center of the frame, focused, composed the frame, and pressed the shutter. But then, to our disappointment, we discover that the sharpness has gone a little. Why? Let's look at the pictures...
1. Focus
There is such a concept - nodal point. This is the point where the rays of light passing through the lens intersect. If the rotation axis coincides with the nodal point, then the object will remain in focus. The position of the nodal point has nothing to do with where the tripod is attached to the camera. | 2. Shift and Shutter Release
In practice, rotating the camera strictly around the nodal point is only possible when using a special tripod head, on which you can set the position for a specific lens. If you turn the camera in your hands or on a regular tripod, this will cause parallax - a shift in the focus plane, because of this, sharpness on the desired object may be lost. |
Fortunately, such parallax is observed only when shooting with a very small depth of field, for example, during macro photography. But we have already agreed that for macro photography it is better to use LiveView and manual focus and, if possible, a tripod. In other cases, parallax can be ignored.
How to use a fisheye lens?
It will be very difficult for a non-professional to use such a lens. Fisheye takes panoramic shots, and at the same time, as it were, rounding and smoothing the corners of the photo.
Such photos are good for dangerous sports, at weddings and bachelorette parties, and at children's anniversaries. There is a visual video on how to set it up and how to film it. It's located here.
Have fun exploring this type of technology!
Shooting with a fisheye lens has become increasingly popular recently. Very often extreme sports, weddings, parties and simply beautiful landscapes are photographed with this lens. Thanks to the fisheye lens, the image is distorted, making it somehow magical, plus with a fisheye you can capture a wide picture, since the image circumference is 180 degrees or more.
There are several ways to take cool photos using a fisheye lens. I'll reveal some of them:
First way:
Radial blur effect:
Second way:
Third way:
Fourth way:
Fisheye lenses designed for panoramic shooting of objects with a capture angle of 180 degrees or more. When working with such a lens, you need to be very careful so that the photographer’s hands or feet and other foreign objects do not get into the subject. In addition, you need to very carefully monitor the horizon line so that instead of a straight line or an arc of large diameter, you do not end up with a parabola concave down or up.
Photography is a fairly complex task that needs to be learned, although for some it comes quickly and without much difficulty. I can offer you a site that offers 5 options for using this lens, with a description of what and how to do, changing the angle and the like nuances.
Well, like... Like any other lens. You stick it into the camera and shoot. Accordingly, the settings are not subject to fishiness, but to the general rules of exposition and plot.
You need to remember a few nuances. The fisheye has a convex front lens, so you can’t put a filter on it. Perhaps even the Cokin system will be out of business (although those who know about it and about light filters in general no longer ask about the settings). There may be filters inserted from the bayonet side, but that's a different story. This also affects safety. If you can put a hood on other lenses and, if something happens, you can hit an obstacle with it, the hood on the fisheye (if any) is small. And if you are used to poking your camera almost in people’s faces, as well as other objects, then you can easily hit this very lens and ruin the lens. The fisheye has a wide field of view, up to a hemisphere. This means that it can shoot everything that is exactly above, below and to the side of that very front lens. Including your surroundings, people sticking out from behind you, and your own body parts. For example, a leg pointed forward. If you care about the subject of the photo, you should try to keep such uninvited artifacts out of the frame. There is no need to expand on the peculiarity of geometric distortion; this topic was discussed without me. Please note: if the horizon (or other line) is above the middle of the frame, it will swell up, if lower, it will bend down. Sun.
The Fisheye lens is capable of capturing images at 180 degrees. That is, this view is wide-angle and can capture much more without using focusing than a regular lens would be capable of. As a rule, a fisheye lens is used in extreme sports, I often see the use of this lens in skateboarding and roller skating, as a rule, the operator films from behind and the result is a rather interesting picture. Although this lens began to be used relatively recently, its first developer was L. A. Borodulin, who developed the lens back in Soviet times.
All modern cameras have automatic focusing functions. So why do photographers still use manual focusing so often? In what circumstances is it used and how to work with it - read in our lesson!
When might manual focusing be needed?
Difficult cases for automatic focusing. Even though autofocus systems have improved every year, they still struggle at times. You've probably encountered a situation where the automation just doesn't want to focus in a certain place. Instead, it begins to “hunt”, focusing the lens back and forth, but never hitting the target. Let's look at the main difficult cases for autofocus.
- Focusing on low-contrast, translucent objects. Try focusing on a smooth white ceiling or photographing the surface of a window glass. Autofocus in such cases may well give up.
- Autofocus may not work when the subject is blocked by foreground objects. The simplest example is shooting an animal in a zoo through a grille: autofocus may well begin to “cling” to the grille. Instead of torturing the autofocus system, in such conditions it is quite possible to switch to manual focusing.
Nikon D600 / Nikon 85mm f/1.4D AF Nikkor
Between me and the model there is translucent glass (it is this that gives the glare). When shooting, autofocus periodically “clung” not to the face, but to cracks in the glass.
Shooting in strong backlight. For example, when shooting against a bright sunset or dawn sun, you will find that autofocus will work worse than usual.
Night shooting. If autofocus can generally cope with the conditions of a city night, then when shooting landscapes with a starry sky outside the city, all that remains is to focus manually. Automatic focus will not help you here.
Nikon D810 /Nikon AF-S 18-35mm f/3.5-4.5G ED Nikkor
Shooting the starry sky. If in previous cases autofocus can still be defeated and forced to focus where needed, then in pitch-black night conditions you will definitely have to adjust the sharpness manually.
Use of non-autofocus optics. There are many lenses that do not support autofocus features. Among them there are both old lenses that have been discontinued and quite modern optics. Many photographers are interested in antique optics, as they give a unique, “vintage” picture. Fortunately, there are a great many lenses that can be installed on modern digital SLRs (including through adapters).
Nikon MF 50mm f/1.2 Nikkor - super-fast manual focus lens
The shot was taken with an old manual focus portrait lens. Such lenses are usually used to play around with bokeh - an interesting blur in the out-of-focus area.
Landscape photography. When shooting landscapes, it often happens that the foreground (which is usually focused on) is located on the periphery of the frame, where there is not a single focus point. One focusing option in this area is to use manual focus. Also, advanced photographers often use hyperfocal distance when shooting landscapes. This requires focusing the lens at a certain distance, and this is easier to do manually using the focusing distance scale on the lens than using autofocus.
Macro photography. In macro photography, autofocus is very difficult. This happens, firstly, due to the fact that the depth of field in macro photography is extremely small. The slightest change in the distance between the camera and the subject (even a few millimeters) will lead to loss of focus. Secondly, the closer the subject is to the lens, the more the lens lenses have to move to focus, and this greatly slows down the autofocus. Therefore, photographers prefer to focus manually when shooting macro, fully controlling the entire process and thereby eliminating possible automatic errors. At the same time, macro photography is characterized by a special method of focusing: not by rotating the focusing ring, but by moving the camera itself a little closer or a little further from the subject. But more on that below.
Nikon D600 / Nikon AF-S 50mm f/1.4G Nikkor (with macro rings)
The smaller the object being photographed, the shorter the required shooting distance. The shorter the shooting distance, the shallower the depth of field and the more difficult it is for autofocus to work.
How to enable manual focus?
On entry-level cameras (for example, Nikon D3300, Nikon D5500), everything is simple: to do this, you need to set the AF/M (Auto Focus/Manual) switch on the lens to position M.
On entry-level models (for example, Nikon D3300 and Nikon D5500), you need to set the A/M switch to the M (Manual) position.
Autofocus is now disabled. Focusing will be done by rotating the focus ring on the lens (highlighted in blue).
Advanced cameras (starting with Nikon D7200) have two autofocus switches: both on the lens and on the camera. How to use them correctly? If the camera is equipped with an AF-S lens equipped with an ultrasonic focusing drive (most Nikon lenses are equipped with it), then it will be enough to move only the switch on the lens itself to the “M” position.
Please note that if you turn off autofocus using the lever on the camera and leave the switch on the lens in position “A”, you can break the autofocus drive and the lens will have to be sent in for repair. The exception is for lenses that have an autofocus mode with manual adjustment - in this case, the autofocus and manual focus switch on the lens will look like M/A-M. This mode will be discussed in more detail below. If you use an AF lens (and not an AF-S lens), then switching the lever on the camera is mandatory: after all, such lenses are physically linked to the camera with a “screwdriver” focusing drive. And to turn off this drive, you need to turn this lever.
To summarize: when using AF-S lenses, it is better to use the switch on the lens. And when using “screwdriver” AF lenses, you must first switch the lever on the camera.
How do you know which autofocus drive your lens has - AF-S or AF? To do this, just look at its full name.
Motorized lens AF-S: Nikon AF-S 50mm f/1.8G Nikkor
When working with AF-S lenses, to enable manual focusing, simply turn the switch on the lens itself to the desired position.
Lens equipped with a screwdriver AF drive: Nikon 50mm f/1.8D A.F. Nikkor. When using such lenses, you must use the switch on the camera.
Now the camera will focus only manually - to do this you need to twist the focus ring on the lens. Please note that the focus ring on different lens models may be located in different places on the lens barrel: a little closer to the camera or a little further. In addition, the focus ring should not be confused with the lens zoom ring (with its help we “zoom in and out” of the picture.)
Manual Focus Methods
So we know when manual focusing may be necessary. Now let's figure out what methods of manual focusing there are.
Focusing at a specific distance
Perhaps the simplest focusing method, especially if your lens is equipped with a focusing distance scale. Just set the desired distance on this scale, and you're done - sharpness will be at the selected distance. This method is well suited for landscape photography when you need to zoom to hyperfocal distance or infinity. This is where the scope of application of this method probably ends. With focusing on “infinity” everything is simple: it is needed when the objects are very far from us.
At what distance does “infinity” begin for a lens? It all depends on the focal length of the lens. The longer the focal length, the further away the “infinity” is. Usually we are talking about tens of meters. In the case of wide-angle optics, we can talk about several meters. But what to do if the subject is close to us, but at the same time, you want to sharpen the entire frame without blurring the background? This is where hyperfocal distance comes to the rescue. The hyperfocal distance is the distance at which, when focusing, everything from ½ of this distance to infinity will fall into the depth of field.
The hyperfocal distance will depend on the focal length of the lens and the aperture value at which you are shooting. How to calculate hyperfocal distance? There is a special formula for this, which can be found in our special article on advanced work with depth of field. But it’s easier to use special calculator programs for this. They are available on the Internet, and special applications for smartphones have also been released. Here are some of them:
It makes sense to use the hyperfocal distance when shooting landscapes, when working with wide-angle optics, where it will give a significant gain in depth of field, allowing you to use it as rationally as possible.
Focusing at a distance will not allow you to focus very accurately, only approximately. This means that this method is not suitable for shooting portraits or reportages with an open aperture.
Landscape focusing at hyperfocal distance
Focusing by changing the shooting distance
This method is often used when shooting macro. Each lens has a minimum focusing distance. Why not choose it? Now that the lens is set to the minimum shooting distance, we simply move the camera to the subject at the desired distance. Holding the device in our hands, we can move it slightly back or forward to catch the focus in the frame.
Focusing using the camera's viewfinder and rangefinder
Modern Nikon SLR cameras are equipped with a special mechanism that can tell the photographer what is currently in focus and where to turn the focus ring to sharpen what is in focus. Let's figure out how it works.
In the viewfinder of the device (in the lower left corner), you can notice the symbols shown below. They also appear during automatic focusing, but when manually focusing the lens they will be most useful.
Symbols for the focusing process in the viewfinder:
| Focused | |
| The lens is focused closer than necessary | |
| The lens is focused further than necessary | |
(flashing) |
Automation cannot determine focusing accuracy. This happens when there is insufficient lighting or when trying to aim at a very uniform, low-contrast object (for example, a white ceiling). In this case, try to combine the focus point in the viewfinder with some contrasting object in your future frame. |
To focus in this way, you first need to select the desired focus point in the camera's viewfinder. This is where the rangefinder will work. Now, focusing on the left and right arrows, rotate the focus ring in the appropriate direction until the circle lights up in the viewfinder. Done: you're focused!
Junior Nikon DSLRs (Nikon D3300, Nikon D5500) use a simplified rangefinder operation scheme. There are no right or left arrows, just a circle to confirm focus. To manually focus on these cameras, simply rotate the lens ring until the same circle lights up in the viewfinder.
This focusing method is very accurate. Therefore, it is also suitable for working with open apertures. With its help, it is convenient to shoot portraits with “handheld” optics.
Focusing on the Live View screen
A very interesting, fast and accurate way to manually focus is offered by the Live View mode. When manually focusing through Live View, the photographer can enlarge the desired area of the image, and this enlarged fragment can be used to ideally focus. In my opinion, this method provides the most accurate focusing. In addition, we can control the sharpness of the frame before shooting, whereas in the viewfinder the situation with sharpness is not so noticeable: you have to strain your eyes a lot to understand what is sharp in the frame and what is not.
So, turn on the Live View screen, select the area of the frame that we will enlarge, and click on the button with a magnifying glass (just like we do when viewing captured images). After this, all that remains is to turn the lens focusing ring, focusing on the device’s screen. I often use this method in the most difficult situations, including when shooting portraits with fast portrait lenses. During such shooting, the depth of field can be a few millimeters, which means that focusing must be perfectly accurate. Since in a portrait focusing is on the eyes, I use Live View to zoom in on the area of the frame with the model’s eyes and focus.
Autofocus with manual adjustment. M/A mode
Some Nikon lenses can operate in a very interesting mode, combining automatic and manual focusing. On some lenses, instead of the usual switch between manual and automatic autofocus, you can find an M/A-M switch.
In this mode, by holding the shutter button half-pressed, you can take control of the focus at any time. As soon as you turn the focus ring, autofocus will turn off, giving focus to you. This is convenient when you want to manually adjust the focus a little before shooting. Let’s say the camera can’t focus, and the lens “scours” back and forth in search of sharpness. At this point, you can immediately take control, focusing the lens where you need it, without wasting time switching to manual focus mode.
Common mistakes associated with manual focusing
Changing the shooting distance after focusing. Remember that when you change the shooting distance, focus will be lost. It is enough for you (or the subject) to move closer or move back (even a little) for the focus to be lost. This is especially critical when shooting with a shallow depth of field: portraits, macro... After you have focused manually, don’t hesitate - shoot right away! Remember that each new shot will require new focus from you.
Selecting manual focus when it is not appropriate. Not knowing how to set up the autofocus system, many novice photographers, when shooting difficult scenes, simply turn it off and try to focus manually. Something successful comes out of this rarely. Manual focusing is not very suitable for dynamic scenes, reportage shooting, sports, and portraits. Remember that it is often better to be able to set up autofocus, understand its operating modes and select focus points, than to switch to manual focus.
The photographer's arrogance plus non-autofocus high-aperture optics. The main mistake of many novice photographers lies in the belief that focusing manually is easy. This misconception is the reason for the purchase of all kinds of high-aperture lenses (Soviet, for example) with manual focusing. They say, why pay for an expensive autofocus portrait lens when for three pennies you can buy an excellent portrait lens with manual focus. Because of such arrogance of the photographer, the shooting may result in 2-3 sharp frames out of a hundred. The reason is that in the camera viewfinder it will be completely invisible whether you focused or missed. Focusing accuracy through the viewfinder can only be estimated very roughly. “But before, photographers somehow focused with this optics,” the reader may say. You need to understand that before there were different cameras, more suitable for manual focusing. They (or rather, their viewfinders) were equipped with special focusing screens that could significantly increase the accuracy of manual focusing. And the technical requirements for photographs in those ancient times were lower, so rarely did anyone pay attention to small focusing errors.
A typical focusing error when working with manual high-aperture optics. In the viewfinder the cat seemed quite sharp. As you can see, in fact, it is far from sharp.
Manual focusing with high-aperture optics is difficult and requires a steady hand and strong nerves from the photographer. In my opinion, manual focusing with a fast lens is most convenient in Live View mode with zoom. In general, I definitely recommend using autofocus lenses for shooting portraits.
Instead of a conclusion
Learning to focus manually is an important skill for a photographer. It will help him out in difficult shooting situations and when shooting with equipment without autofocus. I hope this article has helped you become familiar with the topic of manual focusing. Learning to focus quickly and accurately manually takes practice and training. Don't deny yourself the pleasure of going on a photo walk! Be not a lawyer for your work, but a critic - then each time they will become better and higher quality!
Lenses.
This article will focus on lenses. It is necessary to immediately make a reservation that it is intended mainly for those who are not very versed in technical features and terms. For this reason, some information will be omitted, and the main part will be presented as simply as possible.
Why are lenses needed?
Probably, everyone who has just purchased or is about to purchase a DSLR camera has wondered: what exactly is such a variety of lenses for, if the camera already comes with a lens (the so-called “kit lens”). For normal everyday tasks, such a lens will most likely be sufficient. However, there is an opinion that the more expensive and better the quality of the lens, the better it takes pictures, and this is true, but we must take into account that it is not the equipment that takes photographs, but the person. A lens is just a tool that provides great opportunities, and if selected correctly, it will allow you to obtain the characteristics that you personally lack.
Thus, first of all, you need to decide for what purpose the lens is required, since there are not only universal lenses suitable for many tasks, but also very specific lenses, for example, telephoto lenses or tilt-shift lenses.
So what is a lens? Wikipedia says: a lens is an optical device designed to create a real optical image. In optics it is considered equivalent to a converging lens, although it may have a different form, for example, a “Camera Obscura”. Typically, a lens consists of a set of lenses (in some lenses, mirrors), designed to mutually compensate for aberrations and assembled into a single system inside the frame. Simply put, this is a system of lenses in a frame that focuses the image on the sensitive element of the camera (film or matrix).
Today there are a huge number of different lenses on the market in a wide price range; they are produced by different companies and have different characteristics. Each camera manufacturer (for example Canon, Nikon, etc.) produces “lenses” for their devices, which have their own connector for the lens - the so-called “bayonet mount”. In addition, there are third party companies that produce lenses for different brands of cameras. The most famous of them are Sigma and Tamron; lenses from Tokina, Samyang, etc. are less common. When choosing, you should check whether the lens works stably with your camera and it is advisable to check the lens before purchasing. However, when choosing a lens, the manufacturer is not the most important thing to pay attention to. Much more important are the characteristics, which will be discussed further.
Lens characteristics
The main characteristics of the lenses are:
Focal length (and the ability to change it);
Lens field of view angle;
Aperture;
Maximum relative aperture (sometimes incorrectly called aperture);
The type of bayonet or thread diameter for attaching to the camera - for interchangeable photographic or film lenses.
In addition to them, there are some additional characteristics (various types of aberration, resolution, etc.), which we will not touch on.
Lens focal length
The job of the lens is to form an image on the sensitive element (film or matrix) of the camera. As you know from a school physics course, the focal length is the distance from the center of the lens to the focus (the point of intersection of rays or their continuation, refracted by a collecting/scattering system).
A lens is a type of collecting system that focuses the light entering it onto a matrix. The focal length of the lens is the distance from the optical center of the system to the sensitive element.
If we forget about theory and put it simply, the focal length of the lens characterizes the ability of the lens to bring objects closer. To avoid confusion, you can remember a simple formula: the longer the focal length, the closer the subject will be. The following are photographs taken from the same position, but using lenses with different focal lengths:
A visual representation of the operating principle of a simple lens:
Focal length is measured in millimeters. As a rule, its value is indicated on the lens itself.
Lens Nikon AF-S DX Nikkor 55-300 mm
Code: 130335
Lens Sony SAL-50 mm F/1.4
Code: 105758
Based on the range of focal lengths, lenses are divided into fixed and varifocal lenses. Prime - any lens with a fixed focal length, slang word, shorthand used to contrast with zoom lenses.
Vario lens - a lens with variable focal length (zoom, zoom).
Each type of lens has both pros and cons, which, however, are quite subjective. Primes, for example, are much lighter and more compact, but zooms are much more versatile in terms of focal lengths. In some situations (wedding reporting, for example), zoom will allow you to get the desired composition with minimal effort required to change lenses and constantly move. If you compare primes and zooms that are similar in aperture and focal lengths, you can sometimes get twice the weight of a zoom, which you will certainly feel, and the cost will be higher.
In addition to the focal length, there is another important detail that amateur photographers should know about – the crop factor of the matrix.
The thing is that there are so-called “normal” lenses - the perception of perspective in photographs taken using such a lens is as close as possible to the perception of perspective by the human eye. The parameters of such lenses were calculated in the days of film cameras, which used 35 mm film. The focal length of this lens was 50 mm.
However, the matrices of most modern SLR cameras are smaller in size than the frame on 35 mm film (crop matrix). Because of this, part of the image at the edges, captured by the lens, simply does not fall on the matrix, that is, the viewing angle is reduced. Therefore, for convenience, the term “equivalent focal length” is used for cameras with a crop matrix - a focal length at which the angle of view will be the same as on film at the real focal length.
Simply put, modern DSLR cameras with a crop matrix are designed in such a way that the photographs are slightly closer in comparison with frames taken on a film camera or full frame matrices. It should be noted that lenses in all formats produce the same image, the change in size of which depends only on the size of the matrix. For understanding, see the picture below. The red frame shows the boundaries of a regular 36x24 mm frame, the blue frame shows the boundaries of a 22.5x15 mm digital camera frame.
Typically, camera descriptions indicate the so-called “crop factor” - a coefficient showing how many times the linear dimensions of the matrix are smaller than the dimensions of the film frame. As a rule, for modern SLR cameras this value is in the range of 1.3-2.0. Among them, the most common crop factors are 1.5 and 1.6 (APS-C standard) and 2 (4:3 standard (4/3 and Micro 4/3)). To calculate the equivalent focal length, you need to multiply the focal length indicated on the lens by the crop factor of the camera. For example, you need to compare two lenses designed for different cameras:
1. The SMC Pentax-DA lens is marked “18-55 mm”. The crop factor of the camera on which this lens is mounted is 1.53. Multiplying focal lengths by the crop factor, we obtain equivalent focal lengths (EFL): 28-84 mm.
2. The lens of the Olympus C-900Z camera is marked “5.4-16.2 mm”. The crop factor of this device is 6.56. Multiplying, we get the EGF of the lens: 35-106 mm.
Now we can compare them. The first has a wider angle of view at the wide-angle position, the second - at the longer telephoto position.
Classification of lenses by field of view angle (focal length).
The classification of photographic lenses according to the angle of the field of view or focal length related to the size of the frame is widely used. This characteristic largely determines the scope of application of the lens.
Schematic designation of focal length and their field of view angle: 1. Ultra-wide-angle lens. 2. Wide-angle lens. 3. Normal lens. 4. Telephoto lens. 5. Super telephoto lens
A normal lens is a lens whose focal length is approximately equal to the diagonal of the frame. For 35 mm film, a lens with a focal length of 50 mm is considered normal, although the diagonal of such a frame is 43 mm. The field of view of a normal lens ranges from 40° to 51° inclusive (often around 45°). The viewing angle of such a lens is approximately equal to the viewing angle of the human eye. Such lenses do not distort the perspective of the frame.
Wide-angle (short-focus) lens - a lens with a field of view angle from 52° to 82° inclusive, the focal length of which is less than the wide side of the frame (20-28 mm). Objects in the background when shooting with this lens are smaller than we see. Often used for shooting in confined spaces, such as interiors, but can cause distortion. Also used for landscape and architecture photography.
Lens TAMRON SP AF10-24mm F/3.5-4.5 Di II LD Canon
Code: 153710
An ultra-wide-angle lens is a lens with a field of view of 83° or more, and a focal length less than the small side of the frame (less than 20 mm). Ultra-wide-angle lenses have an exaggerated perspective and are often used to add extra punch to an image. Fish-eye lenses have a viewing angle of about 180° and produce even more distortion.
TOKINA 11-16 f/2.8 DX AF lens for Canon
Code: 163907
Lens TOKINA 10-17mm f/3.5-4.5 AF DX Fish-Eye for Nikon
Code: 163906
Portrait lens - if this term is applied to a range of focal lengths, then it usually means a range from the frame diagonal to three times its value. For 35 mm film, a lens with a focal length of 50-130 mm and a field of view of 18-45° is considered a portrait lens. The concept of a portrait lens is conditional and refers, in addition to the focal length, to the aperture ratio and the nature of the optical design as a whole. The lenses are quite versatile. In photographs taken with this lens, objects in the background are smaller than we see. Another issue is that when shooting portraits, they usually try to blur the background.
Canon EF 28-135 f/3.5-5.6 IS USM lens
Code: 112705
A long focal length lens (often referred to as a telephoto lens) is a lens whose focal length significantly exceeds the frame diagonal (150 mm). It has a field of view angle from 10° to 39° inclusive, and is designed for shooting distant objects.
Lens Olympus M.ZUIKO DIGITAL ED 75-300mm 1:4.8-6.7
Code: 159180
Lens aperture.
Aperture is the second most important lens parameter. Most often, lens aperture is misunderstood as the denominator of the relative aperture (f-stop number). The aperture number, the value of which is marked on the lens, only numerically characterizes the aperture ratio.
Generally speaking, lens aperture is a value that characterizes the degree to which light is attenuated by the lens. Aperture, or more precisely, geometric aperture, is proportional to the area of the active lens aperture divided by the square of the focal length (the square of the so-called relative aperture of the optical system). That is, it depends on geometric parameters - hole diameter and length. The effective lens aperture is the aperture that determines the diameter of the incoming light beam hitting the film or sensor. If we consider the lens as a simple tube, then with the same diameter, more light will pass through the shorter one. Accordingly, in order to improve the aperture of a longer tube, we will have to increase its diameter. When passing through the lens, light is absorbed by the glass, scattered by the surface of the lens, experiencing various reflections inside the lens, etc. The aperture ratio, which takes into account all these losses, is called the effective aperture ratio.
As mentioned above, a lens is a system of lenses in a frame through which light passes and is recorded by a photosensitive element. This frame contains an adjustable light limiter called an aperture.
The wider the aperture is open, the more light will hit the matrix, the brighter the picture will be. The dependence of the hole size on the aperture number is illustrated below.
Changing the aperture by one division changes the relative aperture by ≈1.41 times, and the illumination changes by a factor of two. The aperture scale is standard and looks like this: 1:0.7; 1:1; 1:1.4; 1:2; 1:2.8; 1:4; 1:5,6; 1:8; 1:11; 1:16; 1:22; 1:32; 1:45; 1:64. However, the first aperture numbers on the lenses may not coincide with the standard ones (1: 2.5; 1: 1.7). Typically, aperture numbers are printed on lenses and indicate the maximum open aperture at given focal lengths.
Using the aperture, you can not only regulate the amount of light, but also set the required depth of field (DOF). In other words, adjusting the aperture affects the background blur. The wider the aperture is open, the shallower the depth of field will be (more blurred background). This technique is usually used for portraits, that is, where you need a strong emphasis on the foreground subject. An open aperture forms a circle, a partially closed aperture forms a polygon. “Bokeh”—the artistic blur of point light sources and objects that are out of focus—depends on the type of this polygon. The more edges (aperture blades), the more beautiful the bokeh.
Lenses may indicate one or two (for zooms) aperture values. That is, there is a constant and variable lens aperture.
Lens Nikon Nikkor AF-S 50 mm f/1.4 G
Code: 300145
Lens Sony SAL-1118 DT 11-18 mm F4.5-5.6
Code: 102042
Constant aperture is typical for prime lenses. With zooms, a change in focal length entails a change in aperture ratio (as we remember, it is inversely proportional to the square of the focal length). However, zooms can also have a constant aperture ratio. This is quite convenient, for example, when shooting with flash, since there is no need to take into account changes in aperture. Such lenses are always somewhat more expensive due to the complexity of the design.
Typical values of the denominator of the maximum relative aperture of lenses of different classes:
Small-scale unique lens for the NASA space program Carl Zeiss Planar 50mm f/0.7: 0.7.
Leica Noctilux for rangefinder camera: 0.95.
Jupiter-3 for a rangefinder camera (optical design “zonnar”): 1.5.
Prime lenses for SLR cameras: 1.2 - 4.
Digital autofocus compact camera: 1.4 - 5.6.
Medium price range varifocal lens for a SLR camera: 2.8 - 4.
Inexpensive zoom lens for SLR cameras: 3.5 - 5.6.
Autofocus compact camera: 5.6.
Film compact camera: 8 - 11.
To understand all of the above: a faster lens is one with a smaller aperture value. For amateur photography, the average f/4 value is usually sufficient. Therefore, beginners can be recommended inexpensive f/3.5 - f/5.6 zooms, which are enough to solve most everyday tasks.
Stabilizers and ultrasonic motors.
When shooting in low light conditions or with long shutter speeds, the frames often turn out blurry. Due to hand tremors or other reasons, the frame may be hopelessly ruined. This is where technologies come to the rescue to help stabilize the image.
The camera has built-in special sensors that operate on the principle of gyroscopes or accelerometers. These sensors constantly determine the rotation angles and speeds of movement of the camera in space and issue commands to electric drives that deflect the lens stabilizing element or matrix. With electronic (digital) image stabilization, the angles and speeds of camera movement are recalculated by the processor, which eliminates the shift.
There are three types of stabilizers: optical, moving matrix and digital.
Optical image stabilizer.
In 1994, Canon introduced a technology called OIS (Optical Image Stabilizer). The stabilizing element of the lens, movable along the vertical and horizontal axes, is deflected by command from the sensors by the electric drive of the stabilization system so that the projection of the image on the film (or matrix) completely compensates for camera vibrations during the exposure time. As a result, with small amplitudes of camera vibration, the projection always remains motionless relative to the matrix, which provides the picture with the necessary clarity. However, the presence of an additional optical element slightly reduces the lens aperture.
Optical stabilization technology was picked up by other manufacturers and has proven itself in a number of telephoto lenses and cameras (Canon, Nikon, Panasonic). Different manufacturers call their implementation of optical stabilization differently:
Canon - Image Stabilization (IS)
Nikon - Vibration Reduction (VR)
Panasonic - MEGA O.I.S.(Optical Image Stabilizer)
Sony - Optical Steady Shot
Tamron - Vibration Compensation (VC)
Sigma - Optical Stabilization (OS)
For film cameras, optical stabilization is the only technology to combat “shake”, since it is impossible to move the film itself, like the matrix of a digital camera.
Image stabilizer with moving matrix.
Especially for digital cameras, Konica Minolta has developed stabilization technology (English Anti-Shake), which was first used in 2003 in the Dimage A1 camera. In this system, the movement of the camera is compensated not by the optical element inside the lens, but by its matrix mounted on a movable platform.
Due to this, lenses become cheaper, simpler and more reliable, image stabilization works with any optics. This is important for SLR cameras with interchangeable lenses. Matrix shift stabilization, unlike optical stabilization, does not introduce distortion into the image (perhaps other than those caused by uneven sharpness of the lens) and does not affect the lens aperture. At the same time, it is believed that matrix shift stabilization is less effective than optical stabilization.
As the focal length of the lens increases, the effectiveness of Anti-Shake decreases: at long focal lengths, the matrix has to make too fast movements with too large an amplitude, and it simply ceases to keep up with the “escaping” projection.
In addition, for high accuracy, the system must know the exact focal length of the lens, which limits the use of old zoom lenses, and the focusing distance at short distances, which limits its work in macro photography.
Stabilization systems with a moving matrix:
Konica Minolta - Anti-Shake (AS);
Sony - Super Steady Shot (SSS) - is a borrowing and development of Anti-Shake from Minolta;
Pentax - Shake Reduction (SR) - developed by Pentax, found use in SLR cameras Pentax K100D, K10D and subsequent ones;
Olympus - Image Stabilizer (IS) - used in some models of SLR cameras and Olympus ultrasonic cameras.
Electronic (digital) image stabilizer.
There is also EIS (English Electronic (Digital) Image Stabilizer - electronic (digital) image stabilization). With this type of stabilization, approximately 40% of the pixels on the matrix are allocated to image stabilization and are not involved in the formation of the image. When the video camera shakes, the image “floats” across the matrix, and the processor records these fluctuations and makes corrections using reserve pixels to compensate for the image shake. This stabilization system is widely used in digital video cameras where the matrices are small (0.8 MP, 1.3 MP, etc.). It is of lower quality than other types of stabilization, but is fundamentally cheaper, since it does not contain additional mechanical elements.
Operating modes of the image stabilization system.
There are three typical operating modes of the image stabilization system: single or frame (English Shoot only - only when shooting), continuous (English Continuous - continuously) and panning mode (English Panning - panning).
In single-shot mode, the stabilization system is activated only for the duration of the exposure, which, theoretically, is the most effective, since it requires the least corrective movements.
In continuous mode, the stabilization system operates continuously, making it easier to focus in difficult conditions. However, the efficiency of the stabilization system may be somewhat lower, since at the time of exposure the correction element may already be displaced, which reduces its correction range. In addition, the system consumes more power in continuous mode, which drains the battery faster.
In panning mode, the stabilization system compensates only for vertical vibrations.
It's fair to assume that the presence of stabilization in a lens affects the cost. Therefore, if you have a limited budget, you should decide how critical this parameter is for you. Stabilization makes more sense when shooting distant subjects, low light, or long shutter speeds. Accordingly, if you are looking for a wide-angle or portrait lens for shooting mostly static subjects, you can save on stabilization.
In some cases, quickly focusing on the subject is important to get a great shot. To achieve this, manufacturers equip some of their lenses with more expensive ultrasonic (piezoelectric) motors.
Ultrasonic autofocus lens motor.
Here is a list of designations from various manufacturers:
Canon - USM, UltraSonic Motor;
Minolta, Sony - SSM, SuperSonic Motor;
Nikon - SWM, Silent Wave Motor;
Olympus - SWD, Supersonic Wave Drive;
Panasonic - XSM, Extra Silent Motor;
Pentax - SDM, Supersonic Drive Motor;
Sigma - HSM, Hyper Sonic Motor;
Tamron - USD, Ultrasonic Silent Drive, PZD, Piezo Drive.
Purpose of lenses.
The purpose of the lens is essential. Before we start shooting, the question always arises about what we are going to shoot. By purpose, lenses are divided as follows:
Portrait lens- used for taking portraits. Should produce a soft image without geometric distortion. Telephoto lenses or lenses with a fixed focal length in the range of 80-200 mm (for 35 mm film) are often used as portrait lenses. The classic ones are 85 mm and 130 mm. A specialized portrait lens is designed in such a way that it shows minimal aberrations when focusing from a few meters, that is, when shooting a portrait, to the detriment of image quality “at infinity.” Almost mandatory for a portrait lens is a large (better than 2.8) relative aperture, and the nature of the bokeh is very important;
Macro lens- a lens specially adjusted for shooting from very short distances. As a rule, it is used for close-up macro photography of small objects, up to a scale of 1:1. Allows you to shoot with increased contrast and sharpness. They have a lower aperture ratio than other types of lenses of similar focal length. Typical focal length is 50 to 100mm. In addition, it usually has a special frame;
Long lens- usually used for shooting distant objects. A long focal length lens in which the distance from the front optical surface to the rear focal plane is less than the focal length is called a telephoto lens;
Reproduction lens- used when retaking drawings, technical documentation, etc. Must have minimal geometric distortion, minimal vignetting and minimal curvature of the image field;
Shift lens(shift lens, from the English shift) - used for architectural and other technical photography and helps prevent perspective distortion.
Tilt lens(lens with tilt, from the English tilt) - used to obtain a sharp image of extended objects not perpendicular to the optical axis of the lens during macro photography, as well as to obtain artistic effects.
Tilt-shift lens- a class of lenses that combines shift and tilt of the optical axis. Allows you to use the capabilities of gimbal cameras in small format photography. The largest manufacturers of photographic equipment have at least one such lens in their optics line, for example the Canon TS-E 17 F4L.
Stenop(pinhole) (obscura camera lens, small hole, from the English pinhole) - used for shooting landscapes or other objects with very long shutter speeds and obtaining an equally sharp image from macro distances to infinity in one frame;
Soft lens(soft-focus lens, from the English soft) - a lens with undercorrected aberrations, usually spherical, or with design elements that introduce distortion. Used to achieve the effect of blur, haze, etc. while maintaining sharpness. Used in portrait photography. The so-called “soft focus filters” give a slightly similar effect;
Superzoom(travel zoom) - a universal zoom lens with relatively low weight and a maximum range of focal lengths. It is used with reduced requirements for image quality and increased requirements for efficiency of use and weight.
Ultramind- superzoom, which is characterized by increased magnification of the range of focal lengths, usually starting from five.
Hyperzoom- superzoom, the focal length range of which is usually greater than 15. Common in professional video cameras and compact cameras, for example, Fujinon A18x7.6BERM, Angenieux 60x9.5, Nikon Coolpix P500 (36x), Sony Cyber-shot DSC-HX100V (30x) ), Canon PowerShot SX30 IS (35x), Nikon Coolpix P90 (24x). The lens image quality required in video cameras, especially standard definition, allows the construction of lenses with high magnification. In addition, with the small diagonal of the matrices of camcorders and compact cameras, the dimensions of a zoom lens with a large range of focal lengths are incomparably smaller than they would be with the same parameters for the APS-C format. Studio video cameras can be equipped with zoom lenses with a magnification of 50 and even 100.
Lens mounting methods.
Based on the method of attachment to the body of the device (camera, movie camera, film projector, overhead projector, etc.), lenses are divided into threaded and bayonet - the first are mounted on the camera flange by screwing along the thread, the second are fixed in it by turning. In the simplest designs, lenses are held only by friction or are clamped with a holder in the form of a clamp. Bayonet lens - (from the French baïonnette - bayonet) - a type of connection designed for attaching a lens to photographic, film cameras, video cameras and digital cinema cameras. The main advantage over a screw mount is the precise orientation of the lens relative to the camera, mainly relative to its mechanical and electrical connections. This is especially important for the mechanical transmission of the set aperture value to the exposure meter and the alignment of electrical contacts of modern lenses with microprocessors. In addition, some lens frames require precise orientation to ensure proper installation of accessories such as macro devices, follow-focus devices, and compendiums. The more technologically advanced and cheaper threaded mount was supplanted by the bayonet mount in the 1950s, since the thread did not provide sufficient accuracy of relative orientation. Another advantage of the bayonet mount is faster lens replacement.
There are many different types of mounts available today, so when purchasing a lens (especially on the aftermarket), you need to make sure that the lens is compatible with your camera. One of the two types of mounts that have remained unchanged since the advent of autofocus and digital photography is the Nikon F (F mount). This is a standard for bayonet mounting of lenses to small format single-lens reflex cameras, first used by Nikon Corporation in the Nikon F camera in 1959, and with some modifications still used today, including in digital cameras. Another type of K mount that has survived to this day was developed by Asahi Pentax. The remaining mounts are considered obsolete and replaced with fundamentally new ones, incompatible with previously released photographic equipment.
However, sometimes there is a desire to use in your work some lens with an outdated or unsuitable mount (from the old Zenit, for example) with your SLR camera. For lovers of vintage optics and experimentation, there are various adapters that allow you to install lenses with a different mount.
Adapter M42 - Nikon F with lens and chip.
Lens selection.
For regular shooting at home, portraits of friends, street scenes and much more, a beginner will be more than enough with the standard “kit” lens that comes with the camera. They have focal lengths of 18 - 55 mm or 18 - 105 mm, suitable for the implementation of most ideas. You can buy an even more versatile lens that covers the entire range from wide-angle to telephoto (18-200mm focal length), such as the TAMRON AF 18-200/3.5-6.3 XRLD DII, which remains the world's lightest and most compact zoom lens.
Lens TAMRON AF 18-200/3.5-6.3 XRLD DII Nikon
Code: 136362
If you are passionate about photography and want to immerse yourself in the world of photography as much as possible without spending a lot of money, then it makes sense to purchase a prime lens in addition to a standard lens. For example, everyone’s favorite “fifty dollars” is a lens with a focal length of 50 mm or even 35 mm. With such a lens you can get decent bokeh, appreciate its aperture and feel like a real photographer, moving around in search of composition. Plus, it's lightweight and compact, making it a pleasure to work with.
Nikkor AF-S DX 35mm f/1.8 G Lens
Code: 126699
For shooting distant objects, a lens with a focal length of 70-300 mm is suitable, for example, Tamron SP AF 70-300mm F/4-5.6 Di USD:
Tamron SP AF 70-300mm F/4-5.6 Di USD Lens for Sony
Code: 160453
For those who want to take macro photographs, there are inexpensive solutions in the form of lenses like:
Canon EF 50 mm F2.5 compact-macro lens
Code: 103480
There is an even more budget option - various attachments and macro rings.
Macro attachments are special lenses that screw onto the lens. They produce quite a lot of distortion.
Reversible rings are devices for attaching the lens to the body backwards. The magnification is excellent, but there is no ability to control the aperture ratio.
Macro rings are the most suitable option for trying your hand at macro photography. They allow you to achieve good magnification, however, like any additional glass in the system, they give some distortion and lead to a drop in aperture ratio.
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