Crop factor in cameras

In the description of many cameras, the presence of a full-frame matrix is ​​described as an absolute advantage of the model as opposed to cropped units. Nevertheless, recently you can see a lot of even professional photographers who are not afraid of cropping and make full use of even this technique. The growth of such tendencies leads the thinking beginner to the logical idea that the crop factor in cameras is a relative concept, which means that it requires a more detailed understanding of the topic.

It is possible that among our readers there are one hundred percent beginners in photography, so we will start the explanation from afar. The famous megapixels, by which it is customary in the amateur environment to determine the quality of the camera in the first place, by themselves, a high-quality photo does not yet guarantee - in addition to their number, the size of each individual pixel is also important. That is why modern smartphones with tens of megapixels often cannot provide the same level of quality that a professional camera with “modest” 20 megapixels produces.

The pixels are located on a matrix - a special plate, the size of which differs depending on the model of the unit. Since the time of film photography, it has been accepted to consider the normal size of the matrix, completely identical to the physical size of the frame - most often it is 36 by 24 mm. A full-frame camera is the one in which such a pattern is observed, while, according to the same criterion, full-frame is also determined for digital cameras, where there is basically no film. In pursuit of the compactness of the device, many manufacturers have decided to reduce or "sprinkle" the matrix to one degree or another. To be fair, there are cameras that have a matrix even larger than a full frame, but these are expensive models for the elite.

Based on the above, you can roughly understand why "full frame" is a plus. When the matrix is ​​large and the pixels are relatively small, there is no doubt that they are at least large. Accordingly, when several dozen megapixels are declared in a smartphone, which a priori does not imply full-frame, it must be understood that they are negligible. Recently, the quantity of such "little things" sometimes partially turns into quality, but in general this principle is still to be developed and developed.

In order for users to understand what kind of technology they are dealing with, they introduced such a concept as the crop factor in cameras. Let's explain on the fingers what it means: in fact, it is the diagonal of the standard matrix in relation to the diagonal of the matrix used. If the crop factor is equal to one, then we are talking about a full-frame device.

Based on the above, one could conclude that a cropped matrix is, to put it mildly, not very good. Then, really, another question arises - why manufacturers continue to do, and consumers do not refuse to buy equipment that does not meet high expectations. The answer, as usual, is on the surface: cropped cameras have not only disadvantages, but also positive aspects.

We will start with the good properties of such equipment.

• Compactness. At one time, a good professional camera was a bulky unit that took up a lot of space.If you are a photographer and simply have to carry it with you, then this is not so bad - it's another matter if you need it more for travel, and you don't want to stock up to the very beginning. The crop not only has a smaller sensor, but the camera itself is generally more compact, lighter, and therefore better suited for long trips.
• Cheapness. In the entire camera, the most expensive part is precisely the matrix - this is the sensor that is responsible for taking a photo, it cannot be replaced in any way. The size of the matrix is ​​of direct importance when it comes to its cost, and therefore cropped samples of equipment are always cheaper, sometimes five to ten times.
• The ability to give great magnification. Paradoxically, in some situations, a simple cropped camera can give a result of such a level as if you bought an expensive lens for it. Here's the trick: the larger the matrix, the wider perspective it can capture. Crop, accordingly, captures only a relatively small part of the view, but a large number of megapixels gives a picture of the same resolution. It turns out that you shot the object, as it were, with an approximation. It should be remembered that small pixels of the cropped matrix reduce the aperture, so the advantages of cropping are revealed only when shooting in detail from afar and especially in good lighting conditions.

but Crops are still not a professional's dream - the real photographer wants a full-frame DSLR or mirrorless camera.

I must admit that there is some logic in this, because cropped matrices have a lot of disadvantages.

• Noises. The matrix of a modest diagonal tends to react much more intensively to noise - in other words, it "draws" the light where it actually does not exist. Shooting on a sunny day or in a lighted studio, you will not notice this, but such a unit is definitely not suitable for night work. Video quality on cropped cameras is usually also not impressive at all.
• Limited dynamic range. Shots that combine very bright and very dim objects are quite common. Even the most advanced cameras of our time are much inferior to the human eye, therefore, when focusing, you always choose a drawback: either dark objects will be clearly visible, but the sky will be whitened, or the sky will be beautiful, and dark objects will lose detail. No amount of HDR will give the perfect effect, and with a crop, composite shots with objects of different brightness will be even less successful.
• Trimmed color depth. Advertisers like to talk about displays capable of rendering millions of colors. There are some doubts that a person actually feels such a subtle difference, but the very fact that in nature, with a smooth transition of color, you cannot say for sure where one tone ends and another begins. For a crop, this can just be a problem - he, roughly speaking, is like that average man from the joke, who distinguishes only 16 colors. When photographing monochromatic and high-contrast subjects, you will not see much difference between a cropped sensor and a full-frame one, however, monochrome in crop performance will certainly disappoint you.
• Problems with beautiful blur. The depth of field on cropped matrices is noticeably greater. By itself, this does not mean that it is impossible to obtain an attractive blur in principle, but it is worth recognizing that the task becomes more complicated.
• The coverage of the review is too narrow. This point is the flip side of the fact that the crop allows you to "enlarge" the frame, which was mentioned in the list of its advantages. A small matrix seems to increase the focal length of the lens, and therefore it is problematic to shoot perspective.

From the advantages and disadvantages typical for cropped cameras, in general, one can draw conclusions about how such products differ from full-frame ones. Another thing is that above we considered mainly technical characteristics, and now we will pay more attention to differences in practical application.

To begin with, you need to understand that an expensive and sophisticated camera does not make a green beginner a professional yet. On the contrary, it is crammed with a ton of specific settings, and the calculation is based on the fact that the owner knows how to understand them. Without having the slightest idea about them, the "teapot" is equally likely to screw up the frame on a full-frame camera or on a crop, and then, as they say, why pay more.

Experienced photographers are advised to start with the crop as a cheaper solution. It also has various settings that allow you to delve into their understanding in more detail, learn how to work with light, build a composition, and so on. Learn to capture the frame and transmit it as accurately as possible - in many cases it will not turn out so badly. Only over time, having figured out all the intricacies of the settings, you will begin to notice that, in general, you know what the frame lacks to claim to be a masterpiece, but you can no longer adjust this - the technique does not allow. Then and only then does it make sense to switch to a full-frame model.

When choosing a crop for training, you need to remember one point that can turn out to be a pitfall. The fact is that lenses from an old camera will not always match the new one that you choose in the future, and choosing a camera based on the requirements of old lenses is all the more pointless. If a beginner is obsessed with photography and immediately realizes that he wants to connect his life with this business and will study, including buying a whole fleet of lenses, you can take a full-frame camera right from the start. Otherwise, the very fact of discarding a set of optics along with an old camera can be an example of an unacceptable luxury.

Crop factor is not just an abstract characteristic of a camera, which you may or may not know - in any case, you need to know it in order to choose the right lenses. Above we mentioned that due to its ability to "enlarge" the frame, the crop matrix, as it were, increases the focal length of the lens.

Globally, the crop factor can also be calculated manually - for this, the diagonal of a 35 mm film frame must be divided by the diagonal of the built-in matrix. Please note that 35 mm film does not have a diagonal of 35 mm at all, as some beginners sometimes mistakenly think - its value is usually indicated as about 43.3 mm. For completeness of the formula, it does not hurt to know the diagonal of the matrix itself, however, modern manufacturers in most cases have already understood that the consumer is too lazy to count, and simply indicate this characteristic in the user's manual.

Do not be surprised that the value of the crop factor can turn out to be much higher than one with a penny - today, matrices are sometimes made so small that their indicator can reach 5 or even 6. Accordingly, the higher the crop factor, the more “magnification” your camera will show, and the more distortion it will provide to the lens.

When deciding on a lens for solving certain problems, you should understand that their real focal length is relevant only for matrices with a crop factor of 1, that is, full-frame ones. If the matrix is ​​smaller, the lens will give such a picture as if its focal length is greater than the actual one.

Let's say you have a 50mm lens. On a full-frame camera, it will fully comply with the declared characteristics, on a crop with a crop factor of 1.5 it will be perceived as 75 mm for a full-frame camera, and for a compact device with a crop factor of 2.5 it will be almost analogous to a 125 mm telephoto lens. It means that each lens behaves differently with the camera, depending on what kind of matrix is ​​there, and you need to choose it specifically for a specific model of equipment, not really counting on those technical properties that are written on the package or case.

See the video for the crop factor in cameras.