The perkeo 1 is a non rangefinder camera, you need to guesstimate the distance, it takes practice, but with the lens stopped well down you can afford to be a little out, you can get various shoe mounted rangefinders, there were a lot made in the 50's and earlier, and shouldn't cost the earth and are well worth getting, I have a Voightlander Bessa 66,from 1938, and from the Perkeo was developed, and they are very nice cameras and capable of nice photographs,Richard