Neal Chaves
13-Mar-2012, 17:40
There is a 360 Tele Xenar in a barrel advertised on the site. It interests me because the seller says it will fit in a Copal 3 and I have a 360 lens in a Copal 3 now, but I can't figure this out. My Fujinon W 360 is a 6.3 and come to think of it I don't know of any 360 W types that are 5.6. They all seem to be 6.3 max.
The Tele Xenar is 5.5. Given that the effective focal length is 360mm wouldn't the aperture scale be accurate with the Tele Xenar cells swapped in for the Fujinons? The throat of the Copal is approx 55mm, with front and rear threads both approx 58mm.
I also had an old 360 5.5 Tele Xenar once that came in a Compound and I had a machine shop make a barrel mount for it so I could use it wide open on a Graflex. I still have that barrel and the threads are approx 55mm, the same as the Compound which opened to 5.5.
I think I'm learning something here but correct me if I'm wrong. The size of the aperture for given f stop on a tele lens is based on the flange focus distance, not on the effective focal length and if I swap out the Fujinon W cells for the Tele Xenar in the Copal 3, even though they are both 360s, the aperture scale will not be accurate.
The Tele Xenar is 5.5. Given that the effective focal length is 360mm wouldn't the aperture scale be accurate with the Tele Xenar cells swapped in for the Fujinons? The throat of the Copal is approx 55mm, with front and rear threads both approx 58mm.
I also had an old 360 5.5 Tele Xenar once that came in a Compound and I had a machine shop make a barrel mount for it so I could use it wide open on a Graflex. I still have that barrel and the threads are approx 55mm, the same as the Compound which opened to 5.5.
I think I'm learning something here but correct me if I'm wrong. The size of the aperture for given f stop on a tele lens is based on the flange focus distance, not on the effective focal length and if I swap out the Fujinon W cells for the Tele Xenar in the Copal 3, even though they are both 360s, the aperture scale will not be accurate.