Hi Jim,
Yes, I have the OS version of the lens. It is a very - very - different lens though from the 100-400L or the 300 F2.8. The lens is a monster comparatively...but that is the price of the F2.8 aperture and the relatively long zoom range. I wrote an article about the lens a couple of years back:
http://www.nwpphotoforum.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=37426#Post37426Without a converter, the focus is super fast. As good or better than my 70-200 F2.8 (1st gen). It is definitely good enough to use a converter with, though focus definitely slows down...the 2x is definitely a bit compromised in low light.
In terms of image quality, the 1.4 shows very little compromise. The 2x is a bit dicier, but I use it regularly and it gets surprisingly good results. For me, the bigger issue is the impact it has on AF speed.
At $2700, the lens is half the price of a 300 F2.8 Canon prime and even less than the 200-400F4. That was where I put my money, and I am very happy with it...but I don't hand-hold frequently with it. I don't have the biceps for it. :P
James
James,
do you have the OS version of that lens? I've tried to stick with lenses that I'll be able to hand-hold and for me, IS is absolutely necessary at that focal length.
The other issue for me is the price. I can get either of the Canon lenses used in excellent condition for around $1,000. The best used price I've seen on the Sigma OS version is around $2,700. I'd have to see a LOT better IQ out of that lens to spend the extra cash. And it would have to be just as portable as the 300L and the 100-400L. Yes, the F2.8 would be really nice but not all that necessary for the type of shooting I'm planning to do with it. Maybe for fun I should rent it and see how it compares and then post my impressions here. Gives me a great excuse to get it in my hands and see how it works for my wildlife excursions.
I'll let you know what I find out.
Jim
