Coverage of 300mm Symmar Convertiblegreenspun.com : LUSENET : Large format photography : One Thread
Does anyone have any data on the coverage of the 300/500mm Schneider Symmar convertible lens. I was testing the lens on 11x14 and I was surprised to see that it covered the format. I was shooting at f22 with the lens focused at infinity and there did not appear to be any significant light fall-off at the corners of my final print. Some foreground elements were somewhat out of focus, but this may be a function of the camera set-up and the fact that I did not use any lens tilt. I knew the lens covered 8x10 and I had used it with success on studio images at large magnification ratios (3:1, 2:1, etc.). I normally use a 480mm Red Dot Artar for 11x14 but I was looking for a wider angle. Is it possible that the Convertible Symmar covers 11x14 with little or no movements? Or am I just not seeing the limits of the image circle. Thanks for your help.
-- Dave Willison (firstname.lastname@example.org), July 02, 2001
Check www.schneideroptics.com (knowledge : vintage lens data : large format lenses : symmar).
-- Stefan Geysen (email@example.com), July 03, 2001.
I looked at the Schneider site before but I only found a reference to the the 300mm Symmar. According to the data chart, the lens covers 402mm at f22 focused on infinity. This would cover 8x10 but seems to fall short of the 452mm I assumed for 11x14. This leaves me with two questions: (1) Is the coverage of the 300mm Symmar the same as the 300/500 Symmar convertible? and (2) Does the 300/500 perform beyond the limits of its indicted coverage? I recall reading that some manufacturers provide conservative data with respect to coverage. It also seems possible that with some lenses there might be two areas of coverage. The first area would be an area of criticl focus where the lens does not exhibit softness or light fall-off. The second area would be characterized by increasing light fall-off, etc but may not show the full limits of the lens, especially in a contact print. Having said that, I also recall reading that this type of description might apply differently to older and modern lenses.
-- Dave Willison (firstname.lastname@example.org), July 03, 2001.
Schneider is fairly conservative with image circle specs, and it seems that you have discovered that this lens can cover a larger format than stated. At the 500mm focal length, you won't see much change in image circle size.
-- Michael Klayman (email@example.com), July 03, 2001.
The Symmar 300mm is the 300/500mm convertible. Apparently, most, if not all lenses named Symmar are convertible (I now the 150, 180, 210 ,240, 300 and 360mm are). Schneider later recalculated these lenses so they were no longer convertible, to give better performance (the Symmar-S series).
-- Stefan Geysen (firstname.lastname@example.org), July 05, 2001.