Long focal length. What is the focal length of a lens? What does the focal length affect?

The choice of the lens for the photographer is even more important than the choice of the camera. In this overview you will find a description of focal lengths from 14mm to 300mm... Each focal length has its own specifics, this must be taken into account when choosing a lens. I think you need to start with a whale lens. You can even with a zoom like 18-135, and only then come to the choice of more specialized optics. This is an individual and creative process.

The optimal focal length depends on:

genre of filming
filming locations
specifics of work
creative vision of every photographer

All this can be determined only by having some experience in photography. Below I will share my observations. All information relates to working with. If you have a crop sensor, multiply the focal length numbers by one and a half.

Fish eye

The shot from above is taken on the lens. This lens gives full frame coverage on a crop camera and a circle with black edges on. The angle of view is 180 degrees diagonally. Frames, correctly made with fish-eye, look mesmerizing. The feature of this focal length ( come in from 4mm to 15mm) is that it has a very narrow scope. Fisheye is a lens with the widest possible viewing angle, but without any distortion correction. As a result, we have rounded lines that should be straight, and a very specific perspective. Take this lens with you for a few bright shots. It is difficult to use it for a long time.

14mm

The focal length lens is also very specific. This concerns the geometry of the resulting image. The slightest incorrect tilt of the camera will cause severe distortion. This is especially felt when. In nature, the horizon is easily overwhelmed. The angle of view is very wide - you need to understand if you need it. It has advantages: you can, for example, remove the entire interior of the car from the inside; in any confined space you will not have problems with the viewing angle; in nature, you can make interesting panoramas with a voluminous foreground. Shooting portraits at this focal length can only be done with great care and full height... In general, you need to be extremely thoughtful when shooting people with a lens with such a focal length. This, however, applies to any shooting - here you need to think before taking a shot. A 14mm lens is not an everyday tool.

24mm

24mm- fairly wide angle. When working with a wide-angle lens, you always need to think about what should and should not be in the frame. This focal length is easier to work with. It does not distort space so much and is more in line with ordinary perception. 24mm is very comfortable to shoot indoors. Taking over the entire room will not be a problem. At the same time, geometric distortions are much less pronounced. This is a convenient focal length, you can travel with it (which I would not recommend doing with only 14mm), shoot a reportage inside small rooms, and take landscape shots. For portraits, the 24mm lens is again of little use.

Focal length is usually described in millimeters (mm) and is the main parameter of the lens. This is not a measurement of the actual lens length, but a calculation of the optical distance from the point where the light rays converge, forming a clear image of the object on the digital sensor in the focal plane. The focal length of the lens is determined when it is focused at infinity.

Focal length tells about the angle of view, how much of the scene can be captured with it, and how large individual elements can be. The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.

Fix versus zoom

There are two types of lenses - prime and zoom. Prime lenses have a fixed focal length, while zoom lenses have variable focal lengths. The advantage of zoom lenses is their versatility. They are ideal when you are photographing a wide variety of subjects, landscapes and portraits and want one lens for all occasions. Using a zoom lens also reduces the likelihood of having to change lenses on the camera, which will save time and limit the possibility of dust getting on the lens or sensor.

The main advantages of fixes are their size and weight, as well as their maximum aperture value. Fixes are generally more compact and lighter than zoom lenses.

Also, the fixes have large apertures (from f / 1.4 to f / 2.8), which gives an advantage when shooting in low light conditions, as it increases the possibility of shooting subjects handheld without the "wiggle" or defocus caused by long exposures. Shooting with a prime lens with a large aperture also means you can set a shallow depth of field for portraits and get softer or softer backgrounds (also known as bokeh).

Wide-angle lenses are a popular choice for landscapes, interiors, large groups, and confined spaces.

Fixed lenses in FX format, 50-60mm / in DX format 35mm

Standard lenses are popular because they display reality close to how people see it. These lenses have minimal distortion to show objects in a favorable light. They tend to use large apertures and absorb large amounts of light, allowing for quick shots in low light conditions. Large apertures (f / 1.8-f / 1.4) also keep the image sharp not only in focus, but also in the background. Standard lenses are also popular when shooting portraits in low light conditions where the photographer is unable to use the flash or is looking for a way to take a photo using the available light.

Telephoto lenses FX 70-200mm / DX 55-200mm

70-200mm telephoto lenses are very popular for portraits, product photography, and nature and animal photography. They allow the photographer to get closer to their subject. When creating portraits, the telephoto lens allows the photographer to take a photo at a distance without intruding on the person's personal space.

Super telephoto lenses in FX format 300 - 600 mm / DX format 200-600 mm

These lenses have a good range for sports and wildlife photography where the photographer cannot get close to the subject.

Macro Lenses: FX 60mm, 105mm, and 200mm / DX 85mm

When shooting close-ups, a specific range of lenses are used that allow reproduction up to 1: 1. These lenses allow the photographer to get very close to the subject and reproduce it at a 1: 1 life-size ratio on the lens sensor. These lenses are popular for shooting subjects such as flowers, insects and small objects.

Good afternoon friends! Gradually, we are getting to the key concepts in photography (talking about), without understanding which further advancement in teaching photography and generally conscious shooting is unthinkable, and this is what gives good stable results. Let me give you a quote about following the rules in photography:

Failure to observe this rule results in rubbish.
Ability to observe this rule gives a reliable craft level.
The ability to break this rule gives you masterpieces.

So I think that beginners should strive to master the basic techniques and develop basic shooting skills (confidently shoot in manual mode, understand how to compositionally build a frame, what to focus on in the frame, how to process images ...). And a confident base and experience will surely bear fruit in the form of more interesting results, do not even hesitate!)

Lens focal length concept

Focal length is one of the most important characteristics of a lens. In short and simple, this parameter determines how close the image we can get. When choosing a lens, you should start with it because your shooting style requires certain focal lengths.

I assume that you are already, which we covered earlier. Pay attention to the following diagram of a DSLR camera:

Here the red dotted line indicates the optical axis of the lens, in fact, its center. Here we are looking at a camera with a “cutaway” lens, top view. If you turn the lens with the front lens towards you, mark (mentally, of course!) The center of the circle, then by drawing a perpendicular downward from it, you will get the optical axis. The subject being shot is marked in green on the left. The red lines represent the passage of light through the lens.

Light entering the camera and going in the opposite direction is refracted in different ways. The points of refraction are called principal planes (front and back). From the point of view of photography, it is the back plane that is important, as it is responsible for the refraction of light going towards the matrix. It is also considered to be its optical center.

Hold your attention on this diagram for a moment and take a closer look. There is nothing complicated in this, it is enough to understand once.

The focal length is distance from the optical center of the lens to the focal plane (matrix). See schematic drawing above.

In lenses with a normal focal length (approximately equal to the matrix diagonal), the back plane is located near the diaphragm. In telephoto lenses, due to complex optical schemes, it can be displaced beyond the lens towards the object being shot, in wide-angle lenses - towards the matrix. This is done for the compactness of telephoto lenses and the possibility of creating wide-angle, as a class (since they are difficult to place so close to the sensor).

The lens designers know the exact location of the optical center. And the point that corresponds to the focal plane, i.e. matrix, can be identified by the designation of a circle with a straight line intersecting it on the camera body to the right of the wheel that switches shooting modes (on Nikon).

Naming. The following names can be heard in the speech of photographers:

focal length;
focal;
FR (abbreviation);
focal length (English equivalent);
FL (abbreviation for English equivalent).

How is focal length measured?

Dimension in millimeters, mm. It is better to consider an example. Let's say we have a popular Nikon lens 35 mm f / 1.8G AF-S DX Nikkor. The marking indicates 35 mm, i.e. its focal length is constant at 35 millimeters. Do not pay attention to the rest of the characteristics yet, we will consider them when we talk about lenses.

Another example is the standard kit lens Nikon 18-55 mm f 3.5-5.6 GII VR II AF-S DX Nikkor. It says 18-55 mm, the focal length is variable. That is, by turning the zoom ring on the lens, you can change it from 18 to 55 mm. Looking ahead, these lenses are called varifocal or zoom lenses.

Popular misconception. Sometimes you hear that the focal length depends on something. This is wrong. As described above, the focal length is a physical characteristic of the lens, which is laid down by the designers. It does not change under any circumstances.

What does focal length affect?

Attention! We are approaching a critical part of our conversation to understand. If you understand what will be discussed below, then you will make yourself an excellent groundwork for understanding the composition, which is extremely important. If not ... you can't help but understand! In which case, I am always at your service in the comments.

Parameters that are affected by the focal length:

Viewing angle;
Image scale;
The degree of blur and depth of field;
Perspective (indirectly).

Let's consider everything in detail. Small conventions - we considered in the article about matrices. There we talked about the wider the viewing angle, the larger the matrix. Here we will take a certain size of the matrix and all parameter changes will be considered based on the fact that the matrix does not change. In order to avoid confusion in different focal lengths depending on the size of the sensor, we adopted EGF (effective focal length), which recalculates the focal length in the equivalent of a full-frame camera. We will talk about this in the next article on the crop factor. All of the following examples are from a crop camera, i.e. if the same shots were taken with a full-frame camera, the angle of view would be wider.

Effect of focal length on angle of view

As the focal length increases, the angle of view decreases, and vice versa, the shorter the focal length, the wider the angle of view. Look at examples - shot from the same point at different focal lengths.

It can be concluded that:

The more surrounding space we want to capture in the frame, the wider (shorter focal length) the lens should be.
Conversely, if you need to shoot a relatively distant object, then it is better to prefer a telephoto lens (with a long focal length).

Influence of focal length on image scale

In fact, this is related to the first point. The fact is that with a greater focal length in the final shot, the subject will turn out to be larger. It is said that such a lens will give a higher magnification or larger scale of the image.

For example, we are standing on one point, not moving, and we are shooting a person at a distance of 10 m with a wide-angle lens with an AF of 18 mm. We get a full-length photograph of a person and a lot of space around the edges. By changing the lens to another one, for example, with a FF 85 mm, we will also get a full-length image of a person, but now there will be less empty space at the edges, and the person himself will be larger. As a result, we will get an image on a larger scale.

Effect of focal length on blur

It is possible that you have already heard about this and know that the longer the focal length, the more blurry the background will be. This is why portraitists love telephoto (long focal length) lenses so much. Take a look at the toy example to see how blur changes:

It is worth mentioning that as the focal length increases, the depth of field (DOF) will become shallower, thereby creating blur. Just keep this in mind, we will talk about the depth of field a little later.

Some newbies associate a DSLR (or mirrorless) with the possibility of a strong blurring of the background, which they do when they "grasped" such a device. In fact, blurring the background "into the trash" is not always useful. Yes, so all our attention is concentrated on the subject being filmed, but there is nothing else in the picture! In many cases, it is better to still trace the background details. And an important role in this is played by right choice focal.

Effect of focal length on perspective

To begin with, what is perspective? This is the nature of the transfer of the ratio of the size of the filmed object and other elements in the frame, its shape. Consider the following frame taken with a 17mm lens (wide angle):

There are fencing elements of the road and houses in the distance. In the case of shooting with a wide-angle lens, we get interesting geometric relationships - the scale of the fence will be noticeably larger than the house on the horizon. This is unusual for the human eye, and allows you to build interesting compositional solutions.

In the second case, shot at 125mm (telephoto focal length), the difference in scale between the fence and the house will be smaller.

In general, when shooting subjects from one place with different focal lengths the perspective will not change.

Focal length affects perspective only when objects are close or far away. In the example above (1st photo), you can see that there is a fence in the frame, located close to us. Being close to us, the fence is depicted in the frame in large, and the houses seem small in contrast. Therefore, it seems to us that the perspective is stretched. Another example - if you shoot a distant object with a long-focus lens, and there is another object much further away from it, it will seem as if there is a minimum distance between them, and they are close. A condensed perspective, as they say. This is due to the very far distance between the photographer and the subject, and the difference between the scale of the subject and the very distant background is not so great. This is also seen in the example above (2nd photo). The fence is far away, the house is very far away, but it seems as if the distance between them is not too great.

Wide-angle, short focal length lenses are great for landscape photography... However, it is not recommended to use them when shooting portraits, because the shape of the face will be more elongated and look unnatural. Wide-angle (small focal) lenses are said to stretch perspective, while telephoto (large focal) lenses are said to squeeze it. But this happens primarily not because of a change in the focal length itself, but because of the need to change distance between the subject and the photographer.

Handheld shooting at long focal lengths

Problem.

It can be considered an additional activity for those who want to know more) I propose to move on to a small photo-reasoning and consider a simple situation. In fact, such reflections should be “scrolled” in your head all the time, very quickly you will get used to doing it automatically.

Let's say you are shooting a close-up portrait in the evening with an APS-C camera. There is no sunset yet, but it seems that there may already be problems with lighting, it is not enough. The goal is to capture a beautiful portrait with a strong background blur.

In fact, if you study photography from scratch and consistently read my articles (see), then you understand that your knowledge is not enough. But there is nothing wrong with that - let us speculate with what we have and gradually expand the horizon of the unknown) Do not worry, very soon the puzzle of knowledge will form in your head. Just don't be lazy to think.

We recently talked about the matrix, (ISO). So, at the same ISO on a camera with a smaller matrix (we compare cameras of approximately the same generation and manufacturer), the picture will be more noisy. Usually the noise level of full-frame cameras is taken as a reference. It follows that it is very likely that our camera will be able to register less light with the same quality. Let me explain - shooting with a full-frame camera at ISO 1600, we get an image of a certain noise. When shooting with a camera with an APS-C matrix, in order to get the same level of noise, we already need to shoot, for example, at ISO 400. This means that less light will get in, which is clearly not a good factor in our conditions.

We need to achieve a strong blur. This can only be done with a telephoto lens with a long focal length. The amount of blur depends on other factors (for example, the distance to the subject, aperture), but more on that later. Let's say we chose 105 mm. It's a big enough focal point, and ...

The longer the focal length, the faster the shutter speed should be chosen. This will help to compensate for shaky hands and get a clear, blurry shot.

Excerpt? What? Again, we'll be looking at it in detail soon. In short, this is the exposure time of the matrix, i.e. the time during which the light enters the matrix after pressing the shutter button. Get used to the word "exposure") Now we come directly to the problem of handheld shooting with a lens with a long focal length.

A comparison can be made - imagine that you are in school and you need to point to a small detail on the blackboard. Is it easier to do this with a short pen or a long pointer? Of course, with a pen. The reason is that when using a pointer, the minimum deflection of your hand will result in a significant deflection of the opposite side of the pointer. When using a pen, even if the brush deflects significantly, the opposite edge will not deflect as much. That is, using a long object as a guide, we need to clearly fix the position of the brush.

It's the same in photography, only more complicated. Where we point to on the board is our object to shoot. The lens acts as a pen or pointer. Well, and the brush remains the drive of this whole mechanism) It is important to understand that our firm grip of the camera, a comfortable stand and a short shutter speed act here as a fixture (we reduce the exposure time of the matrix). Even if our brush moves to a significant angle, the shutter will work faster, and the matrix will no longer "see" it.

Let's say we are shooting at a shutter speed that is long for these conditions. What's happening? Light from a point on a person passes through the lens and hits the matrix, forming the same point. Our hand trembled slightly, the camera shifted upward, and light from another point on the person falls on the same point of the matrix. Meanwhile, the matrix continues to be exposed. As a result, we get a blurry image, in the common people "shave". If the shutter speed had been faster, the result of the displacement would not have been recorded on the sensor, and we would have got a clear photo.

So what's the answer? And it is very simple - you need to find a balance, the optimal ratio of all parameters. Minimize problems and achieve the best possible result. It somehow reminds me of university times) This is what we will learn.

What do you need to remember about focal length?

What it is and what it affects, I think you already understood. Now, briefly to repeat the basic information:

Focal length - the distance between the optical center of the lens and the camera sensor.
Frequently abbreviated as FR.
Measured in mm.
The focal length is determined by the lens designers and does not depend on the camera on which the lens is mounted.
Affects the viewing angle and scale of the image, allowing you to "move away" or "zoom in" objects.
Affects the degree of blur and depth of field.
Affects the perspective of the image.
It is more difficult to shoot handheld at longer focal lengths.

The focal length greatly affects the final result, so it is important to learn to “feel” it and choose the right one for specific purposes.

I suggest you go outside and try to shoot, for example, landscapes with different focal points, being at the same point. And observe how close the objects are, how the geometric relationships change. Take pictures of nearby objects, such as a tree branch. You don't even have to shoot, but simply change the focal length (if you have a zoom lens) and observe the changes in the viewfinder.

Over time, you will get so used to your camera and lens that you can guess what the result will be, without looking through the viewfinder.

Good luck and see you soon!

4 comments on What is focal length? What does it affect?

Hello Vlad! I read your photography lessons, I really liked the articles about the camera device, everything is consistent, understandable and intelligible. Thank you for such a presentation of the material, I will wait with interest for the continuation 🙂
Maybe you will make a short announcement on what other topics should you expect articles on? And what materials, from your point of view, are useful for a beginner to study? And then there is so much of everything, you won't immediately understand what you need to deal with first of all)

Good evening, Ekaterina!
Thank you very much for evaluating my work, it is always very pleasant to receive such feedback :) Motivates, tk. it feels like it came in handy for someone!

1. Regarding the announcements - on the horizon there are materials about the crop factor, aperture, shutter speed, ISO, exposure, dynamic range and ... Perhaps, I will not reveal any further cards yet)

2. As for the materials that would be useful for a beginner to study. First you need to understand where the person is, i.e. what he knows at the moment and where he wants to go (what results to achieve) and, based on this, plan the optimal steps to overcome this path. Tell in general outline what you know at the moment and what you are striving for (which genre of photography attracts the most and which works inspire).

Generally speaking, in my opinion, a beginner needs to conduct an educational program for himself on critical aspects. These include the triangle of aperture, shutter speed, ISO, have an understanding of exposure, focal length, depth of field, shooting modes (shutter / aperture priority or manual, it's better not to shoot in Auto) + basic aspects of composition. In general, having a superficial understanding of all this, I would further advise you to shoot-shoot-shoot as much as possible.

At the same time, pay attention to the surrounding space from the position of the "viewfinder". For example, go to work and, observing how the light falls on the flowers, ponder from what angle they would look best, how you would frame them ... In parallel with the practice of closing the gaps in the basic theory of photography, look at many photographs of other people and ponder how and under what conditions they were filmed. I think the latter is very important. Trying to shoot in RAW format, you can even start right away, especially if you have editing skills. RAW provides tremendous editing capabilities, forgiving a lot of mistakes.

It is imperative to learn how to process photos - I am not a supporter of imposing a ton of processing on the original frame, but I think that basic things (exposure compensation, noise reduction, sharpening, working with shadows / highlights, color correction, noise elimination, etc.) should be done, i.e. To. give a noticeably better perception of the final photo. For my part, I can recommend Lightroom.

And gradually move on to more advanced things, but by that time the "newbie" will be able to tell and show a lot of interesting things and understanding what to do and where to move on will definitely be. For basic things, for example, I recommend reading the articles on the website of Alexander Shapoval, he explains it perfectly. And do not forget that practice is the head of everything.

As for my plans, at the moment I have a desire to collect something like a textbook - a consistently written manual, after reading which a beginner in photography could get used to it, learn to get good results and critically approach the analysis of their / other people's photos, the main thing is that learned to think. Plus, he knew how to process his pictures, easily understood them when there were a lot of them and just loved photography)

It is difficult to paint at once, it takes a lot of time. But gradually, materials in chronological order for study will be added to the Lessons section (for now, only technical, about processing later) + periodically I make selections of Friday Mood, where I thematically present the work of other photographers that inspire me and seem interesting.

P.S. To keep abreast of emerging materials, if you wish, I recommend subscribing to email newsletter or a VK group in the upper right corner of the site. And, of course, for all questions you can feel free to contact in the comments or here. If possible, I will try to answer.

Rarely does a photographer dream of a new lens. The reasons for this are individual. But here is how the focal length relates to the compression of space in the frame and distortion, and why this ratio should be put at the forefront when planning to buy a new lens or choosing from available ones, not everyone remembers and knows. Let's take a look at the opinion professional photographer... M.d. Welch is a guest writer for Lensrentals.

It was only after a few days of working on the article that I realized that when we discuss lens models in detail and thoroughly, we completely forget about their nature and behavior in general. Like many photographers, I've already lost track of the time spent reading and looking at reviews. I wasted time saving money for the “same” lens, but I didn’t ask myself the main question - what would bring such a focal length into my photograph?

As it turned out, I'm not alone. At the Shooting the West photo workshop in Nevada, I had the opportunity to speak to a large group of photographers about the difference in focal lengths and lens behavior. It turned out that many photographers, both beginners and experienced masters, do not always understand why they use this or that lens in different situations, and do not understand that the choice should not be based only on the distance to the subject or the quality of the background blur. ...

In this article, I will not waste your time comparing bokeh of different lenses and per-pixel viewing of frames. I will try to outline some criteria for the focal length of the lens, see how the focal length relates to the compression of space in the frame and distortion, and why this ratio should be put at the forefront when planning to buy a new lens or choosing from available ones.

For me, the primary criterion for choosing a lens is the compression of space in the frame, in other words, how much background should be present in the frame behind the subject. To clearly demonstrate the compression of space in portraits, I asked my good friend and fashion model Travis Stewart to work and not move until I took a few shots. I shot at different focal lengths, trying to keep Travis on the same part of every frame.

I started with wide-angle lenses, gradually increasing the focal length. Focal lengths of 16mm, 24mm, and 35mm are rarely used for portraits, but notice how much background is captured in this focal range.

Travis, of course, is present, but the frame is not only about him, and such focal lengths are suitable when it is important to show not only the hero, but at the same time his environment, the place where he lives or works. Distortion or perspective distortion is expected to be present at these focal lengths (we will talk about it a little later), but even at 24 mm the distortion is not so strong as to ruin the picture. You can simply change the composition and, for example, shoot a full-length portrait.

Focal 50 mm and 70 mm are perfectly balanced: Travis is no longer lost in the frame, but stands out - he is "cut off" from the background, at the same time there is a considerable part of the surrounding landscape. These focal lengths are also suitable when you want to show the hero in the environment.

At 100mm, the background is compressed so that the mountain range disappears from the frame, and only the hills just behind Travis are visible. At focal lengths of 135mm and 200mm, the hills seem to get closer. At these focal lengths, the hills appear to be located directly behind Travis, when in fact they are 800 meters away, if not more.

Distortion is another criterion by which focal lengths should be judged. In the frames taken at focal lengths of 16 and 24 mm, you can see how much she changes the face of the model. For greater clarity, I made a series of facial portraits - in them the distortion will be more noticeable. At wide angles, the distortion makes Travis' nose look bigger and his body and face shrink and shrink. At 50 and 70 mm focal lengths, distortion decreases, the nose returns to its normal size, and the body confirms that the owner spends a lot of time in gym.

It is because of distortion that most portrait photographers ditch wide-angle lenses. But here's an example where distortion can help and work for your design.

I asked Travis to hold a bottle of water in front of him and took a series of shots. At the 16mm focal length, the bottle of water looks huge, it becomes the main subject and focus of the frame. At the 200 mm focal length, the bottle size is not at all large and does not attract much attention. Imagine that you have two orders: one from a sports team and one from a sports equipment manufacturer. An image of the athlete holding the ball with his arm outstretched towards the camera is required. By choosing the wrong focal length, you can completely incorrectly place accents in the picture. A wide-angle lens, or a lens close to a wide angle, will make the ball bigger and draw attention to it - the ball manufacturer will be satisfied. The telephoto lens focuses on the athlete, albeit with the ball in hand.

Do not, of course, forget about the ratio of the depth of field and the focal length of the lens. Look at the examples - DOF decreases with increasing lens focal length. All shots were taken at f / 10. The distance from the camera to the subject has a significant impact on the depth of field. In our case, even at the focal length of 16 mm, the background is blurred due to the distance from the camera to Travis.

I hardly discovered anything new, but it was useful to experimentally test how the focal length of the lens affects not only the distortion and depth of field, but also the space in the frame. As a result of this exercise, I now use two fixed focal length lenses - 35 mm and 100 mm - as portrait lenses.

These are the criteria to be used when choosing or buying a lens. If you are working in a small studio or room, a telephoto lens will not only help reduce distortion and give a nice blur to the background, but also compress the space around your subject. When filming the owner of the enterprise against the background of the assembly line, it would be wiser to use a lens with a focal length of 35-70 mm to show the object in its surroundings.

It is interesting to look at the test charts and compare the bokeh of different lenses, but when it comes to work, make sure that you place accents correctly. "

M.d. Welch,special guest writer Lensrentals

Focal length, viewing angle, perspective

It is very often mistakenly believed that focal length is the distance to the object in focus. This, of course, is not the case. Focal length- one of the most important characteristics of a lens, which determines its angle of view, that is, the sector of space that falls into the frame. The shorter the focal length, the wider the angle of view of the lens.

Depending on the angle of view, lenses are divided into wide-angle, normal and telephoto lenses.

Wide-angle a lens that has an angle of view larger than the human eye is considered. The focal length of wide-angle lenses is 35 millimeters or less.

The image obtained with such a lens has a rather pronounced perspective and the background objects seem smaller than we are used to seeing them, but the angle of view of such a lens allows shooting in tight spaces without any problems. Here are examples of photos taken with a 16mm ultra wide-angle lens.

We can see how wide the angle of view this lens has, but it comes at the cost of significant perspective distortion - especially noticeable at the corners of the image. Here's another photo taken with a 16mm lens:

The same thing - a huge angle of view made it possible to fit an enormous amphitheater into the frame. There is also a pronounced perspective effect - small foreground objects appear huge, and large background objects appear unusually small.

Wide angle lenses they are used in cases when one frame needs to cover a large space - mainly in landscape and interior photography. You have to pay for a large angle of view with a specific "aggressive" perspective - the lens distorts the proportions of objects in the foreground and background (see photo with the amphitheater), and also tends to overwhelm vertical lines (see photo indoors).

Normal a lens whose angle of view is close to that of the human eye. Another, more correct definition of a normal lens is a lens with a focal length equal to the diagonal of the frame (in the case of a film frame, 43 mm). The focal length of normal lenses may vary slightly and range from 40 to 50 mm. Compared to a wide-angle lens, the angle of view may appear small with a normal lens, but the lens has a more "calm" perspective. Photos taken with this lens are perceived most naturally, sometimes referred to as “immersive”. Here is an example of a photo taken with a 50mm lens.

Note that the perspective of a normal lens is much more familiar and "quieter" than a wide-angle one. The ratio of the sizes of objects in the foreground and background is familiar to the eyes - this is the main advantage of a normal lens. The flip side of the coin is that in order to photograph a large enough object, you need to move away from it far enough. This is not very convenient and not always possible. A normal lens is best suited for outdoor photography, so called street photography. For landscape and indoor photography, this lens may not have enough field of view to fit everything in the frame.

Telephoto lenses have a focal length of 60 mm or more. It is easy to guess that the longer the focal length, the more the lens "zooms in". Telephoto lenses with focal lengths up to 135mm are often called "portrait lenses". They give a relatively small zoom effect, so they won't be able to shoot close-ups of distant objects, however, the perspective of these lenses is optimal for portrait photography - distortion of the proportions of the face is minimal. Here are two examples: The first portrait was shot with a wide angle (28mm):

The photo shows that the proportions of the face are seriously distorted - it looks too bulging and even the eyes seem to be looking into different sides... Conclusion - if you shoot a portrait with a wide-angle, it will rather be a cartoon!

Another example is a photograph taken with a focal length of 80mm:

Now the proportions are all right! Plus, the increased focal length allowed us to "stretch" and blur the background, now it does not distract us from the main objects.

When shooting portraits even more close-ups (closeup), when the face takes up most of the frame, lenses with an even greater focal length - up to 135 mm are used. Longer focal lengths are rarely used in classic portraits, as poor perspective may make the face look too flat. On the other hand, it can smooth out some imperfections, for example, a too long nose.

Lenses with a long focal length are used when it is not possible to get close to the subject.

Please note that the depth of the landscape is poorly conveyed in the photo - objects in the foreground are about the same size as those in the background. This makes the landscape look unnatural. Telephoto lenses are also used when shooting shy birds and animals, for shooting sports photo reports, when you have to shoot from the tribune, and the distance to the object of shooting can be several tens of meters.

So we have decided which scenes at which focal lengths are better to shoot. For simplicity, we will summarize this information in a small table.

Of course, the ranges of focal lengths are indicative - it is impossible to envisage all genres and all author's ideas in a small plate! In actual situations, the optimal focal length may differ significantly from what is shown in the table.

How do I know the focal length of a lens?

In order to find out the focal length of the lens, it is enough to read its markings. Let's take a common Canon lens- "whale" (in the picture on the left) ...

The arrow in the figure marks the inscription indicating the focal length range - from 18 to 55 millimeters. Such inscriptions are on all lenses without exception. If the number is only one, then the lens has a fixed focal length and does not have a zoom.

Another important point, which must be mentioned - this is the so-called equivalent focal length... Those focal lengths, which were discussed in the section on the angle of view and perspective, refer to film devices, as well as digital ones, having a matrix the size of a film frame - 36 * 24 mm. Such matrices are called "fullframe" or FF (from English Full frame- full frame). They are mainly "inserted" into professional cameras. The majority of amateur and semi-professional devices have a matrix size 1.5-1.6 times smaller than a film frame. Matrices of this size are called APS-C (Advanced Photo System - Classic). What happens if, say, a lens with a focal length of 50 mm is screwed, for example, to a Canon EOS 650D with an APS-C matrix? How will the picture differ from the full-frame Canon EOS 5D Mark II? We look at the pictures ...

If the EOS 5D's sensor covers the entire image formed by the lens, then only the central part of the image falls on the 650D's sensor, it is marked with a dashed yellow frame.

As a result, photos taken with different cameras with the same lens will differ slightly from each other.

It is easy to see that on the APS-C matrix, the 50mm lens seems to give a smaller angle of view. Therefore, to get the same viewing angle as on full frame, you need to reduce the focal length. How much should it be reduced to get the same picture as in the full frame? Right! As much as the APS-C matrix is smaller than the FF matrix, that is, 1.6 times! By the way, the coefficient 1.6 is called crop factor... The larger the crop factor, the smaller the physical size of the matrix.

50mm: 1.6 = 31.25mm

Thus, we calculated what focal length the lens should have in order to provide the same angle of view on the APS-C sensor as a 50 mm lens on a full frame - about 31 mm. In such cases, they say: a lens with a real focal length of 31 mm on a 1.6 crop has an equivalent focal length of 50 mm.

Now let's add an addition to the table with focal lengths, which was drawn above ...

Now let's look at the distance scale of the whale lens and use imaginary multicolored markers to mark the areas of application on it, something like this:

Naturally, the picture is approximate, but it clearly helps to determine for which types of shooting a whale lens is suitable. The range of 18-55 mm was not chosen with ease - it allows you to perform the most popular types of amateur photography. Of course, the possibilities of a kit lens are not endless. They are not recommended to take close-up portraits (close-up, full-frame face); for this, a lens with a focal length of about 85 mm (so that the equivalent focal length is 135 mm) is desirable. If you try to shoot such portraits at a focal length of 55 mm, you will have to do it from too close a distance, which will make the perspective distortion of the face proportions noticeable (of course, not as much as at wide angle, but it will still be noticeable). Also, it is impossible to shoot distant objects with a whale lens due to the lack of focal length.

People often ask me - if you buy a "superzoom" (for example, 18-200 mm), can they make beautiful portraits? Agree, the idea is tempting - to buy one lens for all occasions! Alas, it’s not that simple. On the one hand, the focal length range of the "superzoom" really makes it universal, but on the other hand, due to the relatively low aperture ratio, it cannot always provide a shallow depth of field, which in most cases determines the beauty of a portrait. What depth of field is, what it is for, and how to control it, will be discussed in the next chapter!

Nikon Multi-focal Photo Simulator

See how the field of view of a lens changes with focal lengths and when used on a full frame sensor (FX) and 1.5 crop (DX).

Questions for self-control

Determine the real and equivalent focal length range of your lens.
What types of photography is your lens best suited for?
What types of shooting your lens cannot provide?