One pre-war camera that had a simple but reliable rotating focal plane shutter (1/20 to 1/1000) was the Mercury made by Univex. Unfortunately, it used a unique loading of 35mm film. Most people would never realize if someone was using the similar post-war model, the Mercury II, that used standard 35mm cassettes. The Mercury II came with a triplet lens that perhaps performed as well as the Argus 3C lens. Several interchangeable lenses were available, although these are now scarce. It was also a half-frame camera, popular in the depression yearsys before the war. Its looks were unique due to the shutter housing.