Lens Coverage?greenspun.com : LUSENET : Large format photography : One Thread
First, thanks to those who have answered my previous questions. This is a very friendly and helpful board.
I have had a (several?) recurring problem with my setup, a Calumet CC400 with a Schneider-Kreuznach Angulon 90mm. I don't seem to be able to use much if any camera movements without losing focus. Last week I took a shot with full rise, and a little added rise via a base tilt-type maneuver. The upper corners were vignetted, and a circular, arc-shaped band extending about an inch below that was very out of focus.
A friend told me that the vignetting was likely caused by the bellows, but I have the short bellows wide angle version of the camera. And that still doesn't explain why large portions of my shots go completely out of focus whenever I try to add tilt or swing (and I have attemtped to refocus, BTW, to no avail). Am I using the movements incorrectly?
Any help is appreciated, and thanks in advance.
-- David Gardner (email@example.com), April 12, 2001
No, it's the lens. Even stopped 'way down, an Angulon will barely cover 4x5 with only a little room for movements (less than 1/2" of rise). As to the out of focus problem; I'll bet that the central portion of the image can be refocused sharply, only the periphery is smudged. I'm afraid you need a SUPER-Angulon. Either that, or call it ART and sign your prints "Atgent."
-- Bill (firstname.lastname@example.org), April 12, 2001.
The Angulon just covers 4x5 and has hardly any coverage for movements. For more coverage you'll need a Super-Angulon, Grandagon-N, Nikkor-w or something similar.
The soft band you see is a hallmark of older lenses; there's a circle of good definition that's somewhat smaller than the total coverage, while with modern lenses the circle of good definition is pretty much right out to the limit of coverage.
I think it's probably time to go shopping for a new lens. The 90 f8 Nikkor has about the same coverage as the bigger and more expensive f5.6 Super-Angulon and f4.5 Grandagon-N but otoh the faster lenses can be much easier to focus.
-- John Hicks (email@example.com), April 12, 2001.
I have the 90mm f6.8 Linhof and I love it despite it's limitations -- with bw film at f22 it is equal to or better than my 90 f8 Caltar. I have a couple shots ruined where I tried to shift too much -- still gets me once in a while -- for a press camera like mine, where fewer movements are availible the Angulon is fine. And so small! I use the Angulon on my press camera and the Caltar on my view -- I don't have an extra board to put the Caltar on my press camera.
-- william blake (firstname.lastname@example.org), April 15, 2001.