In this article I decided to tell what kind of beast this is - the lens. Why do you need to bother with it, and why do prices that differ in parameters of lenses vary greatly?
I’ll say right away: the article is more for beginners and curious, as a professional in this field already knows how everything works and what he needs from the lens as a whole.
This is generally a key factor - understanding what you need from technology. This applies to many things, including a camera with a lens, since, first of all, it is a tool for creativity. The rest of the “magic” is done by the photographer and how he uses the tool.
Lenses. What are they for?In this article, I’m talking specifically about lenses without affecting the theme of cameras. A lens is an optical circuit, part of an optical device. There are lenses in many devices, such as microscopes and binoculars. In English they are called camera lens, but to draw an analogy with the Russian word “lens” is not entirely correct. The lens, in fact, consists of a combination of various lenses, depending on the layout of which a final image is formed. The simplest lens effect you've probably seen is a drop of water.
Sony and Olympus cutaway lenses
So, you do not yet know what you want to shoot, and the variety of lenses is confusing. If you remember, before everyone was enticed by the superzoom, they say, you can shoot both indoors and capture the eagle on top of the mountain. Marketers knew that first of all, the buyer wants to shoot in various conditions, and this is the most obvious approach to choosing a lens. I simplified the classification and divided the lenses into classes according to the focal length, and also highlighted their main areas of use.
6-24 mm. Ultra-wide and fisheye: needed for landscapes, architecture and interiors
The name speaks for itself: a wide angle of coverage allows you to take a lot of objects into the frame. Show space and volume. The main nuance is the distortion of objects (distortion) along the edges of the frame and the “overwhelming” of objects, if not removed from the conditional midpoint of their height. A simple example is the interior of a New York subway car. One shot was taken from human height, the second - from the floor to the same lens. One can see how differently the space is perceived.
Shot on an AF-S NIKKOR 20mm f / 1.8G ED lens
Fisheye, aka “fisheye”, allows you to capture even more space, greatly distorting it in the frame. But this is more of his "trick" and the artistic aspect.
Shot on an AF-S FISHEYE NIKKOR 8-15mm f / 3.5-4.5E ED lens
Photo from Nikon
24-40 mm. Wide-angle lenses: needed for architecture, interiors and large groups of people
The coverage angle is smaller, but you can still shoot the same scenarios on such lenses as on ultra-wide-angle ones. There are already not so strong distortions, and there are fewer objects in the frame. Often used for shooting large group portraits to maintain a balance between distortion of proportions along the edges of the frame and the coverage of space.
1-3 shots taken on an AF-S NIKKOR 24-70mm f / 2.8G ED at a focal length of 24mm
The 4th shot was taken on an AF-S NIKKOR 24-70mm f / 2.8G ED at a focal length of 40mm
5th shot with a Sigma AF 35mm F / 1.4 Dg HSM
40-70 mm. "Normal" lenses: needed for everyday shooting and portraits
The name “normal” lens is determined by the focal length approximately equal to the diagonal of the frame. These lenses give a familiar picture close to what the human eye sees. The distortions of space are minimal, there is no optical zoom. Usually it is this range that is covered by whale (complete) lenses of mirrorless and SLR cameras.
1-2 shots taken on an AF-S 50mm f / 1.8 NIKKOR
3-5 shots taken on an AF-S NIKKOR 24-70mm f / 2.8G ED at a focal length of 70mm
70-100 mm. Telephoto Lenses: Needed for Portraits
This category of lenses is one of the most popular in portraiture. Firstly, there is a certain distance from the model, and secondly, there is no distortion of the proportions of the face. An important role is played by the drawing of the lens as a whole and bokeh, but more on that later.
Shot on an AF-S NIKKOR 85mm f / 1.8G lens
100+ mm. Telephoto lenses: needed for sports, wildlife, birds and so on
First of all, telephoto lenses are needed for shooting objects that you cannot get close to, be it a football player on the field, a race car on the track or a lion in Africa. The range of focal lengths is large and greatly depends on what you need to capture. By the way, telephoto lenses are also the heaviest, often a separate focus (monopod) is used for them.
1-3 photos from Sony website. Shot on FE 100-400mm F4.5-5.6 GM OSS at 250, 320 and 400 mm, respectively.
4th photo shot on Tamron SP 70-200mm F2.8 Di VC
What are the lens designsWe figured out the purpose. But it is impossible not to mention the constructive - fixed lenses and zoom lenses.
A fixed lens has one focal length. The range of distances is large, we have already disassembled it. The most popular: 16, 20, 24, 35, 50 and 85 mm. A fixed lens often has a clearer picture due to a fixed group of lenses. Moreover, they are faster than aperture; we will also return to this term.
Zoom lenses are more versatile, so they are indispensable in reporting when there is no way to constantly rearrange the lenses on the camera. Often the reporter has a set of zoom lenses covering the entire main range of focal lengths from 24 mm to 200 mm or more. And again we return to the fact that everything depends on the tasks of the shooter.
Fixed and Zoom Lenses
About other characteristicsI started with the focal length, as this is the most noticeable difference for the buyer. I do not specifically provide a definition of the term; there are a lot of physics and formulas. The main thing to understand: the smaller the value of the focal length, the greater the angle of coverage and vice versa.
But on the lens there are other parameters that also cannot be ignored.
What is a diaphragm and what does it affect
Often denoted by the Latin letter f. Aperture is responsible for two key points: the amount of transmitted light and depth of field. I believe you have heard about the effect of depth of field in smartphones, where it is provided by the presence of a second camera or programmatically.
In the camera lens, this effect is achieved due to a physical phenomenon (a combination of lenses and aperture). The smaller the aperture value, for example f / 1.4, the stronger the effect. Well, the cost is very different. So, lenses with the same focal length but different aperture can differ in price by two or three times. And in the picture you will see the difference.
Zoom lenses usually do not have such an open aperture, this is due to other usage scenarios and lens design. It is precisely these lenses that have a variable aperture setting. That is, the aperture will vary depending on the selected focal length.
The principle of the aperture in modern lenses (animation is available by clicking)
What is depth of field and what does it affect
It also depends on the aperture value. How can you see her? Imagine people standing nearby, but at a short distance from each other. One is closer to you, and you focus on it, the rest on. If you have a fast aperture lens with an open aperture, only the person in front will be in focus in the picture. This will give a depth of space. But if you need all participants in the frame to be in focus, then you need to cover the aperture. There are many nuances, but do not forget: the lens is a tool, and its capabilities must be used for their own purposes.
The last thing that is important to mention is the aperture ratio. I will try to explain as simple as possible. Light plays a key role in the formation of the image, and all the parameters that you set in one way or another control the amount of light entering the camera’s matrix. Shutter speed and sensitivity depend on the parameters set in the camera. But the diaphragm, as I mentioned, depends on the lens. And the more physically it is, the more light you can catch in the frame. That is, with the same ISO and shutter speed settings, but different aperture settings, the frame will be exposed differently - in other words, it will be lighter or darker.
Depth of field example
What is stabilization and what does it affect
Since I am not considering a tripod shooting scenario, it is worth mentioning separately such a pleasant and really useful thing as optical stabilization. As the name implies, it will compensate for the movement of the hands. But do not think that it will allow you to shoot on the run! If you are not a biathlete, then you definitely have a slight tremor in your hands, and frames, especially shot in the evening, may turn out to be somewhat blurry. I'm talking about shooting in a standing position.
More stabilization will help to use longer shutter speeds, again, thanks to compensation for camera movement. Of course, stabilization lenses are more expensive, but this is a profitable investment.
How to choose a lens
A reasonable question will arise in you: "and what should I do with all this?" Before you go to the store, sit down and figure it out for yourself (or with your family if it's a family purchase) what are the main scenarios you usually use. A bit of analytical work, and you will already have a basic list of scenarios and some kind of understanding.
For example, you travel with your family and just take pictures of everything around. Then the popular and already classic 18-55 mm lens will suit you. You can already “read” its parameters and understand what it will allow to shoot indoors, suitable for shooting a group of people (just families, for example) and will make it possible to capture the environment approximately the way you see it with your own eyes. There are few variations on the aperture: often f / 3.5-5.6, that is, you should not expect a particularly interesting picture, but the cost is also low. Another of the advantages, in addition to accessibility, is low weight.
If the budget allows and you do not mind wearing a heavier lens, almost all manufacturers have a 24-70 mm lens with a constant f / 2.8 aperture. It is lighter and more interesting with the picture. You will have to pay with a higher price and weight, and in this scenario, stabilization in the lens will definitely come in handy.
Do you like to take landscapes while traveling? Buy a fixed lens in the range of 16-20 mm. It will be sharp - do you remember that the “fixes” have a large aperture? This will allow you to shoot in the dark. Moreover, it is lightweight.
Want to capture birds or lions on a safari? Useful "telephoto". It can be with a fixed focal length (200, 300 mm or more) or zoom. The price range here is great, it depends again on the diaphragm and the availability of a stabilizer. By the way, in a telephoto lens, the stabilizer is most relevant. The viewing angle is very small, and you see a very distant point, under such conditions, the movement of the hands will be especially noticeable.
Well, if you want portraits with a beautiful pattern and a blurry background, then here you have a niche of fixed lenses, from 35 mm to 135 mm. Price dispersion will greatly depend on the diaphragm, sometimes four, five times! There is no stabilization in this area, mainly due to the complexity of the design of light lenses and the need to give a very sharp picture.
SummarizeNow you understand what is indicated on the lens and what it affects. Of course, you can buy an 18-300 mm lens, and it will cover absolutely the entire range that is useful to you. But you will not get a very clear and interesting shot. You can try to rent many lenses in your city, this is a great way to “shoot” and analyze at home the result captured on your camera. And if you really like it, you can go and buy a similar lens.
I hope that my article will encourage you to further and deeper study of the topic! Try and choose wisely, because only you can give yourself the answer to the question, which lens do you need.