Looking at the Torkel Korling patent jogged my memory a bit. Looks like his original SLR patent inspired others that might have delayed the development of the Japanese SLR in the late 1950s. It is probably no accident that the Nikon F did not appear until 1959, and so on, as the Japanese were waiting for certain important patents to expire that were needed in a modern 35mm SLR. Via Google Patent Search, I see that Folmer Graflex took out some additional patents on the auto diaphragm around 1940. In other words, these were related to the research and development of the Super D, which appeared in 1941 (at least in 3 1/4 x 4 1/4 format; 4x5 in 1948). US Patent 2,236,925 improves on TK's earlier one by providing for interchangeable lenses. Patent 2,273,386 relates to the mirror and diaphragm. Patents 2,365,899 and 2,308,725 seem to be for flash synch; I don't know if these relate to later SLR development, since rangefinder cameras certainly had flash synch before these patents expired. Interestingly, Patent 2,365,899 anticipates the invention being used in a "miniature," i.e. a 35mm camera. Torkel Korling was a top commercial and industrial photographer (later nature too ) who had at least one Life cover. I think it is of a crowing rooster, and he managed to talk them out of putting the Life logo on the cover for the first and only time, since he thought it would spoil the composition. Years ago, I saw an exhibit of photos taken during construction of the Johnson Wax complex in Racine, which was designed by Frank Lloyd Wright. Torkel Korling was the official photographer. He designed and patented what later became the Tiltall tripod, although once again, I doubt he ever made very much money for this. When I saw him, he was peddling his third and last invention, some sort of rotating camera mount that unfortunately had little practical value. He was looking for a business partner who would bankroll his invention, market it, and pay him a royalty. I doubt he ever found such a partner. His earlier patents were assigned to the Folmer Graflex Co., then probably the major manufacturer of professional cameras in the US. We discussed his philosophical approach to shooting and contrasted it with the modern method, which he disdained. In the old days, he said, film was relatively expensive. So, he would carefully set up his master shot and take one or two pictures at the most. Once he knew he got what he wanted, he was done. The modern method was almost the exact opposite- shoot hundreds of photos without a clear idea, in hopes that something usable will turn up in the bunch. --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list