Attention! Lens Industar-69 has connection thread - M39 but the flange focal distance 27.5 mm, standard distance for m39 lenses is 28.8 mm, so you can`t focus to infinity!
Industar 69 m39 f/2.8 28mm is fast, wide angle lens with a fixed focal length for 24x18 frame size camera, so on camera with crop-matrix you have really focal length 28 mm!
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