Quote:A serious question to you, JoJu, since I keep on wondering about it:Let me answer (a part of) this question for you. I tested the 18-35 (not mine, 'fkorz) on my 1D Mark IV (the tinkerer that I am). At f/5.6 the vignetting is noticeable at the shortest focal length (no hard clipping though) but goes away the more you zoom in - it's nigh on invisible at 20mm. Wide open it is invisible at 28mm and 35mm and starts becoming progressively worse from 24mm on down. 18mm f/1.8 setting is unusable if you ask me, 20mm is marginal (both could probably be used for night shooting where the darkened corners would - with luck - blend into the darkness). Whether it depends (a lot) on the focusing distance, I don't know. It could be possible. I did get the degree of vignetting at 18mm f/5.6 to vary depending on focusing distance, but I didn't measure it scientifically. The (silly and half-hearted) test shots (originals with, well, full EXIF and whatnot) are here: https://cloud.mail.ru/public/WxXi/4zDPEou9S
Is it doable to use the f1.8 APS-C zooms from Sigma on the 1.3x crop APS-H Sigma body without encountering problematic vignetting?
Again: this was on Canon 1D4; whether the Sigma's coverage is any different is beyond my knowledge.
The 50-100 should be better in this regard, check out Dustin Abbott's review of that. I never even held it in my hands so I can't give you a first hand opinion. I would have loved to have that lens if I had been planning a total revamping of my kit.