PURPOSE: To fully enlarge and photograph only a necessary range in an object on film by easy operation when photographing with a camera (including a TV camera).

CONSTITUTION: For example, a cursor 12 which freely moves, whose length is changed and whose angle (inclination) is changed is allowed to be reflected within a finder 10. The cursor 12 is aligned with a diagonal line (ab) of the necessary range 22 selected from among the images 20 of the object 200 reflected in the finder 10. Then, the width (x) and the length (y) of the necessary range 22 are found. The value (m) of the ratio of the lateral dimension X of the finder 10 to (x) and the value (n) of the ratio of the longitudinal dimension Y to (y) are obtained. (m) and (n) are compared, and the zoom magnification of an optical system 30 is fixed so that the smaller value may be one. Then, a shutter is released. The zoom magnification to (xy) is stored in a memory, and when (xy) equal to the value in the memory is detected, the final magnification is immediately fixed and the shutter is immediately released.