Choosing the right lens for the camera

Theory

Which lens do you want to buy?

Universal zoom ;
standard zoom ;
fixed lens ;
telephoto lens ;

landscape lens ;
lens for shooting architecture ;
lens for portraiture shooting ;
macro lens .

Choosing a lens is not an easy task, which sooner or later confronts every owner of an SLR camera. In some cases, the lens has a much greater impact on the quality of photos than the camera itself. Many SLRs are equipped with regular lenses (sometimes they are also called "whale", from the English word "kit" - a kit). These lenses give the photographer the opportunity to try their hand at shooting a DSLR, but, as a rule, because of their imperfection, they do not reveal all the capabilities of the camera. Nevertheless, we strongly recommend that anyone who has acquired a SLR camera for the first time take at least a few months with a standard lens to determine their shooting style and then make the right decision when buying more expensive optics. But before moving on to practical tips on choosing a particular model, let's look at the parameters of the lenses and what these parameters can affect when shooting.

Focal length

This is one of the main characteristics of the lens, which determines how far the lens “approaches” or “moves away” the object. Focal length is measured in millimeters. In the "film" times, when most DSLRs had a 24x36 mm frame format, there were no problems with the focal length. But today on the market there are SLRs with different frame formats. There are both full-frame models (24x36 mm) and cameras with a smaller matrix size. The ratio of the diagonal of the full frame and the diagonal of the frame of the camera with a reduced matrix is ??called the crop factor (from the English "crop" - crop, crop). Such a term appeared for a reason. The lens projects a “full-frame” image onto the matrix, but the “cropped” cameras retain only that part of the image that is equal to the size of the matrix. Everything else does not fit on the matrix, and therefore cropped. This means that on “cropped” cameras, the lenses enlarge the image more than on full-frame ones. All lens models can be arbitrarily divided into ultra-wide-angle, wide-angle, standard and telephoto lenses. For full-frame cameras, ultra-wide-angle lenses are focal lengths from 7-8 mm (circular fish eye) to 24 mm. 24 to 35 mm are conventional wide-angle lenses. Lenses with a focal length of 45 to 55 mm are considered standard (or normal). This focal length provides the most natural perspective for the human eye. From 85 mm begins a moderate television range. Lenses with a focal length of 300 mm are powerful telephoto lenses. For convenience of estimating what viewing angle the lens on the camera with a reduced (relative to the full frame) matrix size will provide, the crop factor is used. For Canon amateur DSLRs, the crop factor is 1.6; for amateur DSLRs Nikon, Sony, Pentax and Samsung - 1.5; for Olympus and Panasonic cameras - 2. Multiplying the real value of the focal length of the lens by this ratio, you can get the so-called equivalent focal length. For example, with a full frame, a 35 mm lens is wide-angle, but on a camera with an APS-C format camera (crop factor 1.5) it becomes a standard lens because it provides a viewing angle equivalent to a 52.5 mm lens mounted on a full-frame camera. A similar approach to estimating the focal length is, of course, imperfect. But it allows you to compare the viewing angles of lenses with different frame formats and bring this information to a single standard. Concluding the story about the focal length, we want to recall that on lenses designed for SLR cameras, the real, and not equivalent, focal length is always indicated.

Lens aperture

Aperture of the lens is usually called a value that characterizes the illumination of the matrix or film. Aperture is mainly determined by the maximum size of the relative aperture of the lens. For example, if the lens is marked 50 / 1.4, then its maximum relative aperture is f / 1.4. The smaller the number in the denominator, the higher the aperture, and the more light such a lens allows to pass to the matrix. And if so, then shooting can be done at shorter shutter speeds. In addition, the higher the aperture ratio, the smaller the depth of field the lens can provide, and the more it will be able to blur an image that is out of focus. As a rule, fast lenses are much more expensive than their less fast counterparts. The explanation is simple: they are higher in class, which means they provide higher image sharpness, lower aberration levels and often have a more successful construct.

Image stabilizer

Image stabilization is a technology that mechanically compensates for the angular movement of the camera to prevent blurry images at slow shutter speeds. Today, image stabilization in cameras is carried out in two ways: by compensating for the displacement of the matrix or a special lens in the lens. In the first case, stabilization is ensured using almost any lens. This type of stabilization is used by Sony , Pentax and Olympus.thanks to what lenses of these manufacturers do not need built-in stabilizers. All other companies produce, in addition to conventional ones, also stabilized lenses equipped with a correction lens shift mechanism. Such lenses are more expensive than unstabilized, but, according to many photographers, provide more effective stabilization than cameras with built-in stabilizer.

The principle of operation of the stabilizer based on the displacement of the matrix

If you use a Canon , Nikon or Panasonic camera , then when buying another lens, you should decide: buy a cheaper unstabilized or more expensive, but equipped with a stabilizer. If you shoot stationary objects in low light conditions, the stabilizer will significantly increase shutter speed without blurring the image. Unfortunately, for technical reasons, not all types of lenses can be equipped with a built-in stabilizer.

The principle of operation of the stabilizer based on the displacement of a group of lenses

Lens Design Features

Here we would like to mention several design features that, one way or another, affect the filming process. Firstly, different lenses have different autofocus drives. All modern Canon lenses have a built-in motor for autofocus. Nikon , Sony and Pentax lenses can be equipped with both a built-in autofocus motor and a screwdriver type drive, which allows you to use the motor located in the camera for focusing. However, it should be remembered that, for example, not all Nikon cameras have such a motor, therefore, with such models, screwdriver lenses lose the autofocus function.

Screwdriver autofocus drive

Motors built into the lenses also differ. The fastest and quietest of them are ultrasonic ring motors (different manufacturers can mark them differently, for example, USM, SSM, SWB, SDM). They are used in the most expensive lenses and provide almost silent and very fast focusing. Other types of motors are built into budget models, and they may not give any gain in front of the “old” autofocus screwdriver. Some budget lenses are designed in such a way that the entire front group of lenses moves and rotates during focusing. This can be inconvenient if you plan to use polarizing or gradient filters. During focusing, their position relative to the horizon will be lost due to the rotation of the filter together with the front lens. In more expensive lenses, the front lens group does not rotate.

Third Party Lenses

Of course, every manufacturer of photographic equipment wants only his lenses to be used with his cameras. In addition, each manufacturer has a proprietary mount for optics - a bayonet mount. The only exception is the open 4/3 standard that Olympus and Panasonic use today . Along with the main manufacturers, there are several companies that create optics for different mounts. For example, Sigma , Tamron and Tokina. Typically, the lenses of these manufacturers have a lower cost. If we talk about the quality of their products, then it is better to consider each model separately, since in the lines of third-party manufacturers there are both frankly “weak” (but cheaper than branded) models, as well as completely unique lenses that have no analogues in large photo brands . Despite the fact that millions of photographers use third-party optics, we must not forget that the camera manufacturer always guarantees compatibility only with their own accessories. So, we figured out the basic characteristics of the lenses, and now it's time to move on to practical tips on choosing a lens for various shooting conditions. In each paragraph of this section, we will give as an example several specific models that we would like to recommend. However, you should not think that we offer the only right solution: there are many other models from which you can choose the most suitable one yourself.