Randy
16-Aug-2016, 14:06
Am guessing this has been asked but I can't find the answer through any search.
I have a Wollensak 15" Tele Raptor with a disabled aperture (yes, I buggered it up all by myself). The aperture ring will not operate the aperture but I can remove the rear cell and with my finger, rotate the mechanism and close down the aperture somewhat.
Max aperture is f/5.6. I would like to just close it down to f/8 and leave it there since I don't know how well the lens performs wide open. Problem is - I don't know how to measure. The lens is 15" (380mm) but infinity focus is at about 10" (254mm from lens board to film plane) because it is telephoto.
With the aperture wide open, measuring the opening through the rear element it is 38mm. Through the front it is 55mm.
I just want to know how to measure the aperture opening with this lens to get to f/8, and perhaps f/11. Do I divide the diameter into 380mm or 250mm? Do I measure through the rear or front?
Or, if someone has this lens, if you could remove the rear cell, set it at f/8 and f/11 and measure the diameter of the aperture for me and reply.
I have a Wollensak 15" Tele Raptor with a disabled aperture (yes, I buggered it up all by myself). The aperture ring will not operate the aperture but I can remove the rear cell and with my finger, rotate the mechanism and close down the aperture somewhat.
Max aperture is f/5.6. I would like to just close it down to f/8 and leave it there since I don't know how well the lens performs wide open. Problem is - I don't know how to measure. The lens is 15" (380mm) but infinity focus is at about 10" (254mm from lens board to film plane) because it is telephoto.
With the aperture wide open, measuring the opening through the rear element it is 38mm. Through the front it is 55mm.
I just want to know how to measure the aperture opening with this lens to get to f/8, and perhaps f/11. Do I divide the diameter into 380mm or 250mm? Do I measure through the rear or front?
Or, if someone has this lens, if you could remove the rear cell, set it at f/8 and f/11 and measure the diameter of the aperture for me and reply.