Just got the two rolls (one slide one negs printed) shoot by my recently acquired EOS-3, 28-135 IS and 550EX. Overall not bad at all, however there is something I begun to concern about. High percentage of the pictures shows very strange effect of non-even sharpness across the flat DOF, i.e. about the 20-30% of the left part of the prints shows unsharp, washed out image part, while the rest (center and all the way towards right side) is tack sharp. This isn't DOF issue, I would certainly recognize that and the subject's depth and more or less even across the whole image. On the other hand, the same roll consist images that are OK exhibiting even sharpness as it would be expected. I confused. The camera and the lens have passed a computer-based test in Canon authorized service facility a few weeks ago and no problems where reported. Neither of them suffered any mechanical issue since then.
Any ideas ? I never experienced such effect in my photo history (7 years if extensive shooting and self-education). I would assume theoretically it might be caused by certain optical elements shift inside the lens would it have the history of falling down or similar mechanical shock, however the lens was hardly used by it's original owner and never experienced anything like that according to him (and I tend to trust him), besides of that I guess the lab test would reveal such thing... Can it be caused by IS ? I don't remember which frames exactly were exposed with IS implied, but it was ON most of the time. Probably there is certain technique to follow while IS is in operation ?? Your help is highly appreciated, Regards, Alex Z * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
