> "Craig Zendel" ... > Vignetting caused mechanically from outside the lens (e.g as a result > of filter ring(s)/too lengthy a hood etc.) is increased as the lens > is stopped down. The focused distance also has an effect.
Hi Craig, Chip, and List, Henry is both right and wrong. And Craig is both right and wrong. There missing factor is the relationship between the imaging circle of the lens "exit pupil" and the film-frame. Consider this picture on the Unofficial Cokin Filter System website: (warning, lots of click-throughs for Adorama and Amazon and Minolta products :-) http://geocities.com/cokinfiltersystem/ http://geocities.com/cokinfiltersystem/pressapedframes.htm If there is a dark edge is within the frame, stopping down makes the edge sharper and more noticable WITHIN the frame. But what if the dark edge is just out-of-frame? Stopping down also makes the edge sharper, but now the transition from light-to-dark may now fall OUTSIDE-of-frame, and vignetting will become less noticable! Where is the EOS relevance? When shifting a TSE lens the edge of the image circle can come close to or enter the edge of the frame. If the edge is outside the frame, stop down to reduce vignetting. But if the edge is inside the frame, open up to reduce vignetting. See: http://kosara.net/photo/arsatshift.html Comments? Flames? Cheers Julian Loke P.S. Has anyone used an Arsat lens on EOS? http://kievcamera.com/35mmpc.htm * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
