The optical structure of 5 elements in 4 groups and two ED ultra low dispersion glass effectively reduce the chromatic aberration. There is almost no color distortion. F5.6 constant aperture, small vignetting, providing a wide range of depth of field, soft blur effect, and exquisite circular spot. The closest focusing distance is 0.3 meters, the picture is clear and sharp, the lens distortion is controlled at <=2%. And the mirror door can be opened and closed by rotating the focusing ring.