Attention! Standart 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!My lens was modernized for flange focal distance 28.8mm and tested on my camera to infinity point focus (see photo)!That is, you can use my lens on any mirrorless camera with standart LTM m39 adapter to your cameraand you can focus to infinity!!!Also my lens modernized for minimum focusing distance from 0.4m! That is, you can use this lens also as macro lens!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!Lens can not be used on cameras with internal rangefinder as leica, zorki etc!!!Features:Frame size - 24x18 mmThe focal length -28 mmMaximum aperture - 2.8.Minimum aperture - 16.Number of diaphragm blades -5.Number of lenses / groups - 4/3.Minimum focusing distance (MDF) - 0.8 m. (Minimum focusing distance my this lens 0.4m)Angle of view - 56 °.Flange focal distance - 27.5 mm (Flange focal distance my this lens - 28.8 mm)Type of mounting screw - M39.Type of enlightenment - a single layer.Weight - 55 grammSee please my other item. Maybe will be something interested. Thank you!