Focal length: 21mm
Maximum aperture: F3.4
Minimum aperture: F16
Aperture settings: Click-stops with half-stop detents
Angle of view (diagonal,horizontal, vertical):
For 35mm format (24 x 36mm): 91o, 80o, 59o
For Leica M8 models (18 x 27mm): 74o, 64o, 46o (approx 28mm equiv)
Optical design:
8 elements / 7 groups, 2 aspherical surfaces
Position of entrance pupil: 15.6 mm (to the apex of the first lens surface)
Minimum focus: 0.7m (2.3 ft)
Maximum magnification: 0.03x
Distance scales: Combined metre/feet graduation
Filter thread: 46mm, non-rotating
Dimensions:
43mm length x 53mm diameter (1.7" x 2.1")
55mm length including hood (2.2")
Weight: 279g (9.8 oz)