Bit of an odd one this, but bear with me! I recently bought a grubby Pentax MV and 28mm lens for the challenge of cleaning them up. I've done this and the camera works perfectly, but I can't identify the lens as the finishing ring is missing from the front along with the filter thread. I'd like to at least know who made it so I can look for a broken example to donate its front end. All I know is: It's a 28mm f2.8 It has full stops on the aperture ring with no half stop clicks It was made in Japan It's a Pentax K mount (not PKA) It has macro markings Infinity is at the right hand end of the focus scale. Photos can be found here . Any help to ID this lens would be much appreciated!