The original data sheet, as the mark 1 is no longer listed on the official MOG website.
Optical Construction: Classical Cooke Triplet, 3 lenses in 3 groups
Aperture: 1:2,9 to 1:22
Focal length: 50mm
Minimum Focussing Distance: 0,25 m using the front focussing mechanism (ß‘=-0,245 / 1:4)...