Hi, > Here are two samples at wide open F4 from my 17-40mm on the 5D. > Original small jpegs from the 5D, not touched at all, without flash, > in my fairly dark right now office. :-) > > http://ruminate.net/tmp/17mm_f4.jpg > http://ruminate.net/tmp/40mm_f4.jpg
That's really pretty good for a wide angle lens. I'd say it's maybe half a stop darker in the corner than at center. Maybe a bit more. That's assuming that the light blue Perl books are the same shade of light blue across the bookshelf. Unfortunately, Canon doesn't publish a decent data sheet for their lenses. Otherwise, we'd be able to see a graph showing the relative light fall-off. Check out Zeiss's data sheets for their lenses to Contax and Hasselblad and you'll see what I mean by "decent data sheet". If I recall correctly, wide angle Zeiss lenses for Contax (35mm) exhibit a relative light fall-off on the order of 50 % (one stop) from center to corner. Look at the Distagon 21 mm f/2.8 for example. What would be interesting to see would be an image of a completely uniformly colored subject, completely uniformly lit (no glare, reflections). Then read the pixel values in the center and corner. > I took some photos of my 10D to sell on ebay with my 50mm/f1.4, at > f1.8 I did notice some vignetting. I seem to recall seeing light fall-off like that even on my 10D with the 50/1.4 at 1.4. I would expect some to be left by 2.0... Tom * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
