lense imperfectionsgreenspun.com : LUSENET : Large format photography : One Thread
I need some opinions on how much effect things like cleaning marks etc have on image quality. I use 4x5 and enlarge to 11x14 and shoot almost all B&W. The cleaning marks I'm talking about are on the rear element and can only be seen with a 7x loupe while pointing the lense directly at a quartz halogen lamp about 6in away. I know that any kind of scratch or other imperfection will have an effect on contrast but does anyone know or have an opinion as to how much? I recall reading something written by Ansel himself stating that even a visible scratch on the rear element would probably not have much of an effect unless struck by direct bright light! I am of the opinion that such minor imperfections have more of an effect on value than actual image quality as long as you're not enlarging a 4x5 to 5ftx7ft. Any other opinions? Also has anyone ever heard of or read anything about computar symmatrigons?
-- Ron LaMarsh (Ronlamarsh@aol.com), February 11, 1998
For what you describe, I doubt those marks will be a problem for you. I have a 10" WF Ektar with moderate polishing marks on the *front* element. The only time I notice it on the photograph is when I am shooting directly into very bright light, such as sunlight reflected on water.
-- Peter Hughes (email@example.com), February 18, 1998.
This is horrible!. How can you be expected to produce fine images with such horrendous cleaning marks on your lens? Please send this monster to me immediately and I will make sure it receives a proper burial.... right inside my camera pack. Please be sure to also include a Zone VI 8x10 lensboard with it. As far as computar symmatrigons are concerned - I think a good virus program will be able to eliminate them from your computar.
-- Joe Alsko (firstname.lastname@example.org), March 15, 1998.
Lens imperfections can be a very tricky thing.
Whenever you're BUYING a used lens, particular from a New York dealer, any and all imperfections, short of a cracked or missing element, are totally insignificant. "Trust me, this will NEVER show in your negatives!"
Whenever you're SELLING a used lens to one of these guys, any flaw, even a speck of dust on the UV filter protecting the front element, will seriously degrade the image and make it almost impossible to re-sell. "Would I lie to you?"
-- Sergio Ortega (email@example.com), March 30, 1998.