I recently acquired something on eBay and this lens came with it as an extra. It seems like a decent lens for something that was essentially free but the aperture ring is tight. Glass looks real good and focus is smooth but what's best thing to do about the aperture tightness? It actually rotates fully and seems to have loosened up a tiny bit with repeated rotations but I think it's gonna take some other action to make it really useable. I hesitate to just drop a bit of oil in there. I have some acetone and maybe a touch of that will loosen up some dried grease? Either way, I think I risk getting something deeper into the lens where I don't want it to go. I'm not seeing an easy way to remove the ring but the aperture stop is a screw. Maybe I remove that and the aperture ring will rotate off allowing me to get at the threads? Any input appreciated. Thanks, Tom
Bell & Howell Lumax 1 inch/25mm f1.9
Posted 13 December 2017 - 01:35 PM
The Lumax were made by Wollensak. As far as I know your one-inch Lumax is a Petzval design or a dialytic four-elements lens. Wouldn’t be a wonder, if the two inner elements were plano-concave. Yes, you undo that set screw and can then separate the focusing barrels.
Posted 13 December 2017 - 01:38 PM
Thanks. Will give that a shot this evening. Actually, I was going to give it a shot this evening anyway but it's nice to know that I'm going in the proper direction rather than just removing screws because they happen to be exposed.