HerbChong wrote:
FWIW, my copy of the Sigma 12-24 in Pentax mount is quite sharp at f8-f11, but i know that quality is all over the place with Sigma lenses. it's probably almost as good as my Nikkor 12-24 DX or the Nikon mount Tokina 12-24 that i have tried. two major drawbacks with the Sigma is that it flares much more so than either the Nikkor or the Tokina and doesn't accept filters on the front of the lens without severe vignetting.
Herb...
Herb
I found that the Sigma 12-24 was every bit a match and in most cases exceeded the Nikon 12-24. Plus with the option of full frame with the Sigma there is a real plus compared to the Nikon. Finally at several hundreds of dollars cheaper for the Sigma there is some real gain. I had never before used a Sigma and the test results I have seen from most of their lenses (resolution, yellow bias etc) it is not a choice I would often entertain. But the 12-24 seems a bit special so consider it when you are choosing this focal length zoom
Interesting test!
Looks like the Oly 21 is the clear, undisputed winner.
What I find intersting also, is that the Olympus performance doesn't falter at f16, due to diffraction on digital, where as the Sigma clearly gets very soft at f16. Talk about "digital optimization" to fight diffraction making newer lenses more adapted to digital sensors than older ones!
I have avoided using myy Oly at f16 up to now, maybe that was an unnecessary precaution.
here is another oly21 versus sigma 12-24 test. this time a closer shot. i took several images slightly moving the focus ring and found the best oly at f8 and then repeated for the sigma. at f8 the sigma was way behind so i repeated the test with the sigma at both f8 and f11. what appears below are the best oly best sigma at f8 and best sigma at f11. at closer focusing distances, the oly / sigma gap is wider ... at least on my copies of the lenses
no they are center, a little below the mid point. see the pics above in this thread where the sigma did better. i was surposed at the results too. here is the whole oly pic
here's another test. oly on left and sigma on right. center crop a little above midline. these are best samples from each lens taken at f11 and various focus distances. the roof is about 50-60' away
Edited by jonboring on Jun 21, 2006 at 08:02 PM GMT (Reason: clarify)
ok, new topic. i am getting different results on the oly between a cameraquest adaptor and a pro-technique. maybe i screwed one on not so good ... i want to try again and see if it happens again. but the cameraquest is producing much better results at least in this initial test.
