It is the shortest focal length that I could find to cover 35mm format and having a solid metal casing was an appeal (no plastic). The lens is designed to go on a Viewlex projector therefore no helicoid and no aperture adjustment. For now it is mounted onto M42 17-31mm helicoid from eBay but It could live inside the shell of a Russina small lens (Jupiter-8?). I will post images of the adaptation but for now here are some close-ups (OOC) DV230045 by gnarlydog, on Flickr DV230050 by gnarlydog, on Flickr The lens is very sharp in the center but a bit soft on the edges. It does give just a hint of swirl bokeh at the right distance. At infinity the lens measures 48mm long, and the barrel is only 42mm wide, so a rather compact lens. Adding an aperture control in the future (from an old lens body) might make it a bit more versatile.