I've read the existing threads on this lens, but they're fairly old now, and had no experience or pics using this lens. I saw that Robert O'Toole was planning to use it at Bosque last November - any comments from that, Robert?
I'm considering this lens as a replacement for my Canon 100-400 L IS, as that lens seems noticeably unsharp at 400mm & f/5.6 with my 50D; sharpness seemed OK with my 20D, but AF was always hit-or-miss near minimum focus distance - often off by 1/2" in one direction or the other.
Anyway, my real question is how the Sigma 150-500 OS compares to the Canon 100-400 IS in terms of sharpness, at its longest focal length, with AF, using good technique, on a tripod.
And yes, I know primes would be sharper, but I can't afford $3K+ for a lens.
Have you considered running micro-adjust on the 100-400 before going to a Sigma? Or perhaps seconding to Canon for calibration? The 100-400 should out-perform the Sigma in a heartbeat!
My experiences with the Sigma, albeit a year old, was that it was a very disappointing performer. Unless you desperately need IS (OS), you should consider Sigma's 50-500... In my tests, again over a year old, it's performance blew away the newer 150-500 OS.
I love the 50D and 100-400 combination. There is nothing wrong with the AF and its very sharp .. even at 400.
If you are not sure test it .. not in normal use but using a target ... also wise open. I'm amazed at some of the comments I hear about this lens and almost seems that is treated as an amateur tool .... I just laugh and keep making razor sharp flight images !!!
I have not used the lens but you might contact James or Blake Shadle I think they are familiar with the lens.
I have to say that I would take the 100-400 over the Sigma any day. I use the 100-400 and the 50D as my main camera/lens combination, and am pretty satisfied with it. The 100-400 could be a tad sharper at 400mm, but this is hard to notice even at 100% magnification, and it is easy to create publishable quality images at 400mm. At 300mm it is even sharper.
Just a word to the wise - the 150-500mm Sigma is very soft from 400mm and up - to me unacceptably so. I purchased one several months ago. One week later after testing I sent it for service to Sigma. Seven weeks later I received it back - little different than I had sent it in, plus the inclusion of added internal dust. I returned it again after finding that Sigma had outsourced the service. Sigma themselves attended to it this time. It came back one month later clean - but no better optically. Sigma assured me that this was the best it would ever be. So I got rid of it. I use a Nikon 300mm with a 1.7x TC for 500mm and the results are far far superior to the Sigma.
Thanks everyone! I always prefer to learn from other people's experience.:D I think my next step is to send my Canon 100-400 in for cal, and afterward try a micro-adjust if the cal doesn't improve it enough.