Marc, again thanks for these posts and your web site - a great resource. Even the great 60's RF cameras could not stop the SLR tide. Several of them are shown in the picture of the article. Wish that the older Leica prices had kept down! I got something from Sherman's column this time. Critical frequency for contrast in lenses is about 30 lines per mm. The article on mirror lenses using excentric aperture disks was very interesting; I might yet try this. Had to be Keppler. Special mention for the Soviet article on their problems. Wish someone that was in the USSR at the time could comment!