Russian Soviet Helios-40-2 85mm f/1.5 Best portrait manual lens for M42, Pentax SLR/DSLR Camera. NEW! Russian Camera lens Helios 40-2, 85 mm f/1.5 considered to be one of the very best portrait lenses! Focal Length - 85 mm (85.18 mm), Angle of view - 28  ', Focal Length - 85 mm (85.18 mm), Angle of view - 28 , Focal Length - 85 mm (85.18 mm) Mount - M42. Fits Pentax screw-mount cameras, Yashica screw-mount cameras, Praktica SLRs, Soviet Zenit SLRs and anything else with the native M42 mount. Mount - M42. Fits Pentax screw-mount cameras, Yashica screw-mount cameras, Praktica SLRs, Soviet Zenit SLRs and anything else with the native M42 mount. Angle of view - 28  , Number of lenses / groups - 6 / 4, Front vertex focal distance - -26.85 mm, Rear vertex focal length - 44.52 mm Relative aperture - 1:1,5; Frame size - 24x36 mm; Distance from first to last the surface - 81.53 mm Distance from first to last the surface - 81.53 mm Light diameter of the first surface - 56, 9 mm; Lens filter thread size - 67mm; FOV corresponds to a 135mm lens on a 35mm camera