I keep learning things I never knew. While cleaning the 1937 8.5cm f4.5 Apotar and shutter on an original Jsolette I learned that the Tessar lens formula patent ran out in 1902. Almost every lens after that was a variation on the 4 element in 3 groups Tessar lens formula (sometimes 4 in 4). In seems every lens that ends in "ar" up to the mid 1940s or beyond is actually a Tessar formula lens. This camera was worked on by a brute, but remarkably the camera is so well constructed that I'll be able to put it right. Whoever had it before me got so frustrated in not being able to remove the top plate that they drilled two eight inch holes in it to clean the viewfinder. Even chipping one of the view finder lenses. I plan on mixing epoxy with lamp black - tape some wax paper over the holes, and let gravity do it's thing. It doesn't need to be light tight, but I don't want dust getting in since I cleaned it. Which didn't require removal of the top plate. Here are the before and after lens cleaning + plus the drill damage.
Pre-cleaning
Post cleaning - required unmounting the lens & checking collimation afterwards. 55mm f3.5 ai micro from here on
Drill damage
Unlike other Isolettes - the original has the film moving - from the back - right to left. The model II goes the opposite direction. I may add a cold shoe on the unused right flat of the top plate for my tiny add on rflx light meter or the waist level finder. Cement and screws would be permanent, but will likely use alien tape which won't harm the top. And something new next post.
Oct 06, 2024 at 08:41 PM
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