(1) When shooting, the camera lens has a focus, and all the pictures are the clearest on the focal plane (focal plane).
(2) In addition, due to the small aperture of the lens, there is still a certain range before and after the focal plane, and the imaging is relatively clear (the dispersion circle of aberration is within the specified range), which is called the depth of field.
(3) In that year, Minolta took the lead in adopting autofocus AF technology and achieved success in the market; But because of patent infringement, Xerox lost a lot of money.