Edge and Center sharpness on an old f/8 Super Angulongreenspun.com : LUSENET : Large format photography : One Thread
I've acquired on old f/8 coated Super Angulon in a Compur 00 shutter, which I've had cleaned so that it functions well. I've shot a couple of sheets of film with the lens and I must say that I am dismayed at edge sharpness (I've shot at f/22 and f/32.) Center sharpness seems OK, but toward the edge of the field (not the image circle--the 4x5 field with no shifts or rises) there is a loss of definition. Does this match the experience of others. Has anyone tested one of these for maximum sharpness and definition at a variety of f/stops? This is an old wide angle design, and the edge to edge sharpness you might find on, say, a 24mm Nikkor meant for 35mm, doesn't seem to be there.
-- Tony Galt (firstname.lastname@example.org), May 06, 2002
Tony: Are you absolutely sure the rear element is screwed in so that it snugs up against the shutter recess instead of hitting the retaining ring or edge of the lens board recess? A lot of people are using lenses which are mounted wrong and it can cause what you're talking about. Try screwing the rear element in with the lens in hand but not on the board, feel the definite stop when it is in all the way? Compare that to the feel on the board. If it feels mushier then you're binding up on the retaining ring or the edge of the hole for the recessed part of the board. Just a thought. What you describe is unusual, especially since you're not at the edge of the image circle.
-- Kevin Crisp (KRCrisp@aol.com), May 06, 2002.
I had the same problem with a 1970's 90mm f8 S.A. I tried checking if the rear element was seated correctly (it was) and the same problems ensued. My 90mm optar was even sharper at the edges. I don't know if Schneider occasionally has a lens that slips by their quality control, but I was surprised. I sold my lens with stated defects, and use my optar for nature shots (it's a lighter lens anyway) If i end up shooting anymore interiors, I may look into the 80mm or 110mm super symmar (rental of course)
-- Eric Verheul (email@example.com), May 06, 2002.
I wonder if I'm being too picky. I blew a negative shot with this lens up to 11x14 and sharpness toward the edges was certainly acceptable at that size--individual bricks in a building were clearly resolved even toward the edge of the field. (I used a front rise.) Perhaps I'm looking at my negatives with too much magnification--a habit learned with 35mm slides. I wonder if lenses designed for 35 mm don't have to have higher resolution because of the need to blow negatives up much more than with LF?
The lens is well-seated on the shutter and cosmetically in good shape.
-- Tony Galt (firstname.lastname@example.org), May 07, 2002.
I have a SA f8 90 from 1954 around and mine is sharpest at f32-45 but has no chance against my nikkor f 4.5 90mm from 1985. But sometimes I use it because it works not so contrasty then the nikkor but up to 12x16 inch it is very difficult to say that is the shoot from the nikkor and thad is it from SA if you not go to near and take a loup! But mine has focus shift when closing down in a distance between 1-4 meters! Test yours at f45!
-- Armin Seeholzer (email@example.com), May 07, 2002.