My lens was modernized for flange focal distance 28.8mm and tested on mymirrorless camera to infinity point focus!That is, you can use my lens on any mirrorless camera with standart LTM m39 adapter to your any mirrorless camera and you can focus to infinity!!!Also my lens modernized for minimum focusing distance from 0.1m! That is, you can use this lens also as macro lens!Helios-89 m39 f/1.9 30mm 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 30 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 - 1.9 FIXEDMinimum aperture - 1.9 FIXEDNumber of lenses / groups - 6/4.Minimum focusing distance (MDF) - 0.1 mAngle of view - 56 °.Type of mounting screw - M39 LTM.Type of enlightenment - a single layer.Weight - 70 grammSee please my other item. Maybe will be something interested. Thank you!