The concept and principle of micro-focus lens?

Macro photographic lens refers to a special photographic lens that can be used for macro or close-up photography without installing close-up accessories such as close-up mirror, close-up collar and close-up track leather cavity.

Macro camera lens is a kind of camera lens for shooting tiny objects or retaking small pictures. This kind of lens has quite high resolution, minimum distortion and aberration, high contrast and good color reproducibility. Macro camera lens has good close-range resolution, which can keep the image quality unchanged in the whole focusing range. General photographic lenses are mainly used to shoot scenes within the usual focal length, and cannot be directly used for close-ups. To shoot close-ups with general photographic lens, close-up accessories such as close-up lens, close-up collar or close-up leather cavity must be added to the lens before it can be taken. However, after adding close-up accessories such as close-up lens, close-up collar or close-up leather cavity to the general photographic lens, it is in the "close-up" state and cannot be quickly restored to the normal photographic state from the "close-up" state. In other words, it is difficult to take close-ups alternately by using general photographic lenses and close-up accessories. Macro photography lens is different. Its close-up does not depend on other close-up accessories, and all close-up operations are carried out on the lens itself. It can connect the focal length from close-up to infinity, so that it can be quickly adjusted from close-up to ordinary photography, which provides convenience for photographers to alternately take close-up photography and ordinary photography.

Macro photographic lenses generally have two structures. One macro photography lens adopts the structure of built-in telescopic lens barrel, and the other adopts the structure of exchanging the front and rear positions of optical lens groups in the lens. The former, in ordinary photography, the photographer can focus normally only by turning the focus ring of the lens. If he wants to take a close shot, as long as the focus ring that has been rotated to the nearest focus position continues to rotate, he can move the entire optical system of the lens forward synchronously with the built-in lens barrel, thereby increasing the image distance and achieving the purpose of close shot. The latter obtains higher image magnification by changing the front and rear positions of the optical lens group in the lens, thus achieving the purpose of close-up.