The more detailed the specific performance indicators of the DSLR camera lens and its specific role,

The standard lens focal length of a 35mm camera is 28mm and 70mm.

For example, the f=, 38mm 115mm (35mm equivalent) on the lens means that the focal length of the camera is millimeters, with 3x optical zoom capability, and the diagonal angle of view is equivalent to the 38mm and 115mm focal length of a traditional 35mm camera.

Lens Marking Explained AI is an automatic maximum aperture transfer technology. Released in 1977 for manual shots. This logo does not appear in the lens name, and the minimum number on the aperture ring of the AI lens is green.

AI-S is an automatic shutter index delivery technology. Released in 1981 for manual shots. This logo does not appear in the lens name, and the minimum number on the aperture ring of the AI-S lens is yellow.

Classification of cameras

Professional cameras are also called SLR cameras, and complete cameras should be called single-lens reflex cameras. The unique design of the mirrors and prisms of these cameras allows the photographer to observe the image through the lens directly from the viewfinder. After the light passes through the lens of the camera to the mirror, it is refracted to the upper focusing screen and forms an image, through which the photographer can see the outside scene in the viewing window.

When shooting, when the shutter button is pressed, the mirror pops up, the front shutter curtain opens at the same time, and the light (image) through the lens is projected onto the photosensitive part (film for conventional cameras, CCD or CMOS for digital cameras) to make it sensitive, and then the mirror immediately returns to its original shape, and the image can be seen in the viewing window again. The lens of a professional camera can be taken off completely and replaced with another lens to obtain a different shooting effect.

There are so many types of lenses in professional cameras, and many of them are even more expensive than the body. The various functions and indicators of the fuselage must rely on excellent optical lenses to complete. The best effect of the applicable focal length of the current lens is achieved by the image conversion of the lens group in the lens.

How to choose a wide variety of camera lenses. It depends on the type and route of shooting you are good at to determine what lens you should buy the most, and don't blindly buy it, resulting in duplicate focal lengths.

I will ask this question, I should be a beginner, and I will use the most popular words to give you a brief explanation.

There are two more commonly used parameters: focal length aperture.

Focal length, focal length is generally used in mm (millimeter) units The size of the main image shooting angle.

The 135 camera is our common SLR, and the 50mm lens is the standard lens, because the field of view of this focal length is close to the range we see with one eye.

The smaller the focal length value, the wider the angle at which it can be shot, the larger the lens below 50mm is also called a wide-angle lens.

The larger the focal length, the smaller the angle at which the shot can be taken, the farther away Lenses higher than 50mm are also called medium telephoto lenses.

The size of the aperture is expressed as follows: The smaller the number, the larger the aperture, for example, the aperture of f2 is greater than f8.

I choose a lens according to a different route.

The more conventional way is:

Shoot landscapes, large scenes with a wide-angle lens.

Shoot portraits or subjects that you can't walk into with a medium telephoto.

If you don't want to shoot with serious distortion, you can use a standard 50mm lens.

Please give an example of what parameters.

Indicates that the lens is fixed-aperture.

Explains that the lens is variable aperture.

35mm means that the lens is a fixed focal length, and 35mm is used in a full-frame body and is a small wide-angle lens.

50mm indicates that the lens has a fixed focal length of 50mm, and it is a standard prime lens for full-frame bodies.

200mm means that the lens has a fixed focal length of 200mm, and it is a telephoto lens used in a full-frame body.

The 18-200mm illustration lens is a zoom lens, which can be varied from wide angle to telephoto.

If these lenses are used on the APS-C body, the focal length should be X-factor. Canon, Nikon, Sony, Pentax.

If it is a tourist aircraft, it is required to be relaxed and convenient, then it is equipped with a wide-angle large zoom, such as 18-200, 16-85, etc.

If you shoot macro, you need a specialized macro lens, fixed focal length, 60mm, 90mm, 100mm. Usually the magnification ratio is 1:1

If you are looking specifically at portraits, then a fixed focus of 70-150 is good.

If you are a sports journalist, photographing animals and birds, then you may use 70-200mm, 300mm, 500mm to fix the aperture.

There are some unimportant signs on the lens, such as ultrasonic motors, special coatings, special optical glass, etc.

The logo is different for each manufacturer. Which brand are you talking about.

A DSLR camera lens is a lens, and its parameters are mainly two:

The larger the aperture (aperture), the better, and the bigger the more expensive.

Focal length (zoom range): The larger the zoom range, the more convenient it is to use, but the larger the zoom range, the resolution tends to decrease.

There are a few other parameters:

Lens mount. The size of the thread of the attached mirror.

The number of lenses that make up the lens, several pieces and several groups.

Coating condition. The presence or absence of aspherical mirrors.

Macro situation. With or without a zoom motor.

These are generally illustrative parameters (indicators), and some also give some measured data, curves, and so on.

The lens of the SLR camera usually has a few data first, the focal length unit is mm second, the aperture, no unit, if the prime lens only indicates the maximum aperture, if the zoom lens indicates the aperture value at different moments with the focal length, only the starting value is marked third, the lens aperture, the unit mm indicates the filter size, it is convenient to buy the appropriate size filter Fourth, the minimum focusing distance, generally cm or m as the unit, indicating how much the lens minimum focusing distance is.