My Retina I was originally equipped with the Schneider Kreuznach Retina-Xenar lens, but it was badly fogged. I bought a junker of the same model but with the Anastigmat Ektar lens and used it to replace the damaged lens on the camera. That turned out to be something of an ordeal as the whole lens and shutter assembly has to come out in order to fine-tune the infinity focus. The only way to check the accuracy of the infinity adjustment is to reassemble the camera, so I felt fortunate to only have to go through procedure twice before getting it right. I probably would not have tackled the job at all were it not for the availability of some excellent instructions provided on the web site of the Retina expert, Chris Sherlock.
I have several models of the Retina line; the Retina I is the oldest and simplest, and it is a bit slower to shoot than the others because of the manual shutter cocking and the knob film advance. The basic simplicity of the Retina I is part of its charm, however, and the high-quality design and construction makes it a pleasure to handle. The Retina I is similar in regard to features and quality to the Zeiss Ikonta 35 and the Voigtländer Vito II from the same post-war era. I would find it impossible to distinguish photos shot by one from the others, or to pick a favorite among them.
Some photos from the Retina I: