Lengthen the camera lens focal length is zoomed in or out
2, the shorter the focal length of the optical zoom lens smaller, the shorter the focal length of the lens the greater the perspective. the focus is reduced, the subject changes from far to near.
When the telephoto lens is stretched, the focal length also increases.
1, the longer the focal length of the optical zoom lens larger, the longer the focal length of the smaller the angle of the lens;
