StephenT
13-Jun-2014, 19:50
I recently purchased a Sinar F with a Schneider-Kreuznach Super Angulon 90mm/f8 Technica in a Compur shutter. It has Linhoff on the barrel. The lens is definitely coated, but it does not have a focusing lever to open the shutter - I have to use the B setting to lock the shutter open for focusing (never seen this before - all my other large format lenses have that capability).
The shutter goes from B to 1/500.
It came mounted on a Sinar board, but the retaining ring was on the front element (actually the shutter, of course), and was screwed all the way forward on the shutter. Normally, I believe the retaining ring is found on the interior side of the lensboard, but this lensboard hole is just a bit too small, so it has to be installed on the shutter assembly on the exterior side of the board. The rear element is then screwed into the shutter and the retaining is used as a "spacer" to limit how far the rear element can be screwed into the front element.
Removing the lens, it appeared to me that the rear element could protrude dangerously close to the aperture blades. Remounting the lens, I did not screw the ring all the forward on the shutter, but left plenty of room so the rear element would have plenty of space between it and the aperture blades.
Is the entire length of the lens/board/shutter a critical dimension? Are all lensboards the same thickness? It seems to focus fine from what I can tell on the ground glass, but I believe there might be design limits on the distance between the front and rear elements.
At a maximum aperture of f8, it's a little hard to tell on the ground glass what may lie in the periphery of the image circle.
Has anyone had an experience like this?
Any input would be appreciated before I start experimenting.
Thanks.
Steve
The shutter goes from B to 1/500.
It came mounted on a Sinar board, but the retaining ring was on the front element (actually the shutter, of course), and was screwed all the way forward on the shutter. Normally, I believe the retaining ring is found on the interior side of the lensboard, but this lensboard hole is just a bit too small, so it has to be installed on the shutter assembly on the exterior side of the board. The rear element is then screwed into the shutter and the retaining is used as a "spacer" to limit how far the rear element can be screwed into the front element.
Removing the lens, it appeared to me that the rear element could protrude dangerously close to the aperture blades. Remounting the lens, I did not screw the ring all the forward on the shutter, but left plenty of room so the rear element would have plenty of space between it and the aperture blades.
Is the entire length of the lens/board/shutter a critical dimension? Are all lensboards the same thickness? It seems to focus fine from what I can tell on the ground glass, but I believe there might be design limits on the distance between the front and rear elements.
At a maximum aperture of f8, it's a little hard to tell on the ground glass what may lie in the periphery of the image circle.
Has anyone had an experience like this?
Any input would be appreciated before I start experimenting.
Thanks.
Steve