Is there a difference between zoom lens and zoom lens?

The English name of OpticalZoom is Optical Zoom, and digital cameras rely on optical lens structure to achieve zoom. Optical lens is an indispensable part of machine vision system, which directly affects the imaging quality and the realization and effect of the algorithm. There are many specifications of optical lenses, which can be divided into short-focus lenses, medium-focus lenses and telephoto lenses from the focal length. There are wide-angle, standard and telephoto lenses according to the size of the field of view; Structurally, it can be divided into fixed aperture fixed focus lens, manual aperture fixed focus lens, automatic aperture fixed focus lens, manual zoom lens, automatic zoom lens, automatic aperture electric zoom lens, electric three-variable (aperture, focal length are all variable) lens, etc. The optical zoom mode of a digital camera is similar to that of a traditional 35mm camera, that is, the scene to be shot is enlarged and reduced by moving the lens. The larger the optical zoom coefficient, the farther the scene is photographed.

Optical zoom is achieved by changing the position of lens, object and focus. When the image plane moves in the horizontal direction, the visual field and focal length will change, and the farther scenery will become clearer, making people feel that the object is moving forward.

So, there must be two ways to change the perspective. One is to change the focal length of the lens. In photography, this is optical zoom, which changes the focal length of the lens by changing the relative position of the lens in the zoom lens. The other is to change the size of the imaging plane, that is, the diagonal length of the imaging plane. In today's digital photography, this is called digital zoom. In fact, digital zoom does not change the focal length of the lens, but changes the viewing angle by changing the diagonal of the imaging plane, thus producing an effect equivalent to the focal length change of the lens.

It can be seen in the market that some digital cameras with long lenses have more room for the lens and photoreceptor to move inside, so the zoom factor is also larger. However, some CMOS digital cameras generally have no optical zoom function, because the roots in the fuselage do not allow the photosensitive devices to move. Nowadays, the optical zoom factor of digital cameras is mostly 10, and cameras with zoom factor of 30 are also on the market.

Both zoom lens and zoom lens have the function of adjusting the visual field width, but when we adjust the zoom lens, the focal length will be adjusted together, so when we ZoomIn or ZoomOut, there will be no out-of-focus phenomenon, but after adjusting the F value, the zoom lens still needs to adjust the focal length again to make the image clear.