This unique & sharp Helios 58mm f/2 44-2 lens has a nice and narrow mount with the rear element sticking out. This feature makes the lens great for Lens Whacking or Free Lensing. For normal, still photography this M42 lens does a good job and has the 58mm focal length I prefer over a 50mm. This lens is so well built it feels like you’re holding a hefty machine that will take a beating and keep on working.