When a digital camera takes pictures, the lens can be enlarged or reduced, that is, the focal length can be adjusted. Do you have a mobile phone with this function?

Due to the size limitation, ordinary mobile phones do not have optical zoom function (of course, some mobile phones do, that is, digital cameras with retractable lenses from the back). The so-called magnification refers to "zooming", which enlarges or narrows the scene by changing the viewing angle (mainly used for framing). Another term is "focusing", which refers to adjusting the focal length so that the influence of the photographed object falls on the focal plane. Generally, good mobile phones have auto-focus systems, while some mobile phones use Quan Jingshen lenses similar to those used in the past (that is, when the aperture is small enough, the picture is clear, but the picture quality is not good because of the small aperture), and the shooting effect is very general.

In fact, at present, it is enough for us to take pictures with a mobile phone with autofocus function, which can ensure the image quality. There is a saying in photography that "zoom basically depends on walking", that is to say, the effect achieved by zoom lens is not as good as that achieved by fixed focus lens. The so-called "fixed focus is not light."

After all, the camera function of mobile phone is its sideline. If you pursue the effect, you'd better use a special digital camera (but I personally don't think you need a card machine, because many mobile phones have lost the effect of a card machine).