What do you think of the card camera? Is the higher the zoom ratio, the better?

The English name of Optical Zoom is Optical Zoom, and digital cameras rely on optical lens structure to achieve zoom. The larger the optical zoom coefficient, the farther the scene is photographed. Optical zoom clearly tells us that the best lens is nearly three times that of optical zoom, and more is not good.

Due to the limitation of cos4 law, the amount of light entering the center and edge of the lens is directly proportional to the viewing angle of the lens and the magnification of cos4. Therefore, a lens with a large zoom ratio is destined to have a very unbalanced light entrance ratio at the central edge of the wide-angle end and the telephoto end.

In fact, if you want image quality, the ideal situation is fixed focus, but zoom is the general trend. It is still necessary. Just don't pursue it too much. The picture quality of about 3 times is still relatively guaranteed.

In addition, after the lens is scaled down, the requirements for anti-shake are higher. The bigger the light becomes, the more focal segments there are, and the wider the application range, but the prime number of the lens will be reduced. So for general photography, it is enough to choose 3-5 times of optical zoom magnification. If it is too big, you need a tripod to cooperate with the shooting, otherwise it is easy to break the film.