Today, I am going to tell you about the crop factor. All people who are interested in photography, from amateurs to those who make money on it, are faced with the recalculation of the lens by crop. Only the latter perfectly understand what it is about, and they operate with this. For the rest, this text is intended. It’s time to go back to basics and break down everything you need to know about the crop factor. Let’s fill the gap!
What is A Crop Factor?
Before talking about the crop, it is imperative to start with the camera matrix, which is inextricably linked with it. It is located inside the carcass and is a light-sensitive sensor. It is an essential element for any camera, from the smartphone camera to the latest models of major brands. The camera obscura is the only option where a matrix is not needed.
In simple terms, the matrix is an analog of photographic film. In analog cameras, the image passed through the lens and fell on the photosensitive layer of the film. In modern, digital, everything is the same, and only it gets on a photosensitive matrix. It is formed there and then stored on a memory card.
The so-called full-frame (FF, Full Frame) matrix has a size approximately equal to the frame size of 35 mm film. Of course, this adds to the size of the camera and the price of zeros. To reduce all these indicators (including smartphone cameras, it is impossible to imagine a full matrix there), manufacturers have reduced this sensor.
There is an established set of such shortened matrices on the market. For example, 1.5, 1.6, 2, 4. All this is the crop factor. The number indicates how many times this matrix is smaller than the full frame. So, if you multiply the dimensions of the matrix with a crop of 1.5 by one and a half, you will get the dimensions of the FF (full-frame).
In everyday life, this indicator is used mainly to determine the lens’s focal length and install it on various cameras.
Chronology of The Appearance of Crop Matrices
In analog photography, there was no such thing as a crop factor. Although there was a wide range of frame window sizes on the market, each corresponded to a particular focal length of the lens, which was considered normal.
For example, for large cameras with a frame size of 9×12 cm, a lens with a focal length of 135mm as standard, for a medium format 6×6 – 80mm, and for a standard one – 50mm. And on each of them, such a combination of frame size and the standard lens produced more or less similar results.
Lenses with the same focal length on cameras with different frame sizes will behave entirely differently. We think of the 50mm as more of a portrait lens. However, in the medium format, it would be wide-angle. And on a large one – ultra-wide-angle.
Despite such discrepancies, there was no crop in the days of analog photographic equipment: it was not necessary to recalculate the values of lenses and translate – an appropriate set of lenses was produced for each type of equipment.
There are now many lens adapters and cropped sensors, and you need to do some calculations to understand how a particular lens will behave on your camera.
How Does Crop Factor Work?
The lens projects a round (yes, round) image straight into the camera’s body. Frames crop this circle to a familiar rectangle. Thus, only part of the entire image is captured. The smaller the matrix, the smaller this rectangle. Accordingly, a smaller piece of the passing image will be obtained at the output. When shooting with a cropped matrix, the camera, as it were, cuts out a rectangle 1.5 / 1.6 / 2 times smaller than a full-size frame.
Having photographed on a full-frame camera and cut a rectangle 1.5 / 1.6 / 2 times smaller from the photo in the center on a computer, you will get precisely the same frame as you would get on a cropped matrix.
The crop factor is how many times the sensor is reduced compared to the full-frame. To understand how a lens designed for a full matrix will behave in a crop, you must multiply the focal length by this value.
For example, in a camera with a 1.5 cropped sensor, a 50mm lens will produce an image of 50 x 1.5 = 75mm. If you screw a 75mm lens onto a film camera, you will get a picture with a similar angle of view. Although the lens on the crop is 50mm, and on ff-75mm.
You may also like to read: Cleaning the Camera Matrix: When and How to Do It?
Crop vs. Full-Frame
The most popular crop factor in affordable cameras is 1.5 and 1.6. On the one hand, the larger the sensor, the higher the quality of the resulting photos. It is also affected by the quality of the lens and the level of lighting. But the fact remains, the matrix decides.
There are even medium format digital cameras, where the sensor size exceeds the standard full-frame. For example, Hasselblad or the Fujifilm GFX line, where the matrix size can reach 40mm. They cost like a good car, but their images can be printed on a billboard.
The quality of a full frame is the image’s resolution, level of detail, clarity, lack of noise in low light. If you send pictures taken under the same conditions to crop and FF for printing, then the first one will lose in all respects.
In addition, a full-frame is easier to crop: if during processing you often crop the frame to the required piece, then FF will not lose quality from this. On the other hand, the crop will go strongly in pixels with a detailed approximation.
The other side of the coin is that the full frame is essential primarily for those who work with the image, and a camera is a working tool for him. If you shoot for yourself, do not spend a lot of time processing, and appreciate compact cameras, then the crop is your choice. That too can produce a good picture that will suit your needs and request.