Infrared lens, short-wave, 50 mm, f/N 2

Working distance: distance between the front end of the mechanics and the object. Percent deviation of the real image compared to an ideal, undistorted image. Measured from the front end of the mechanics to the camera flange at infinite focusing. Given with no mount attached. See layout drawings.

Main optical specifications
Focal length	(mm)	50
Image circle diameter	(mm)	21.0
Angle of view	(deg)	23.7
Working distance range (1)	(mm)	500 - inf
ƒ/N		2
Wavelength range	(nm)	900-1700
Distortion (2)	(%)	0.41
Back focal length	(mm)	9.5

Mechanical specifications
Focusing		Manual
Mount		C
Outer diameter	(mm)	71.0
Length (3)	(mm)	67.5
Mass (4)	(g)	400