04-21-2012, 01:58 PM
Since I have two of those maybe I can add some thoughts.
It seems you've already decided against the 100-400L, or have you? I use the lens a LOT and it just doesn't give me any dust problems on a 7D. I've only had to clean the 7D sensor around 3 times in the two years or so I had it. The water resistance, or lack thereof, is a minor problem. I use it unprotected in moderate rain and after some time (some hours) you can get condensation forming on the internal optical elements. But it also dries out quickly afterwards. The question therefore is how much water are you likely to subject any lens to?
I recently also picked up the Sigma 120-300 OS. As far as I can see Sigma don't make any claims on water resistance on that either. I haven't really let it get wet yet, so I'm unsure how that performs. The internal zoom and focus means it does not have the extension which is the weak spot for water ingress of the 100-400L. In comparison though, it is a much heavier lens. Turning the zoom ring is much slower than the push-pull of the 100-400L. To my eyes, the image is slightly soft at f/2.8 and sharp at f/4 onwards. AF speed is comparable. No other image issues to report for now.
I haven't had a chance to try it with extenders yet, which is the main reason I got it, as I need more than 400mm with AF. I did not consider the 500mm class zoom lenses as they didn't offer enough over the 100-400L at the cost of their other problems. In particular I'd rule out the Tamron on the basis it has a backwards zoom ring and no HSM or VC.
It seems you've already decided against the 100-400L, or have you? I use the lens a LOT and it just doesn't give me any dust problems on a 7D. I've only had to clean the 7D sensor around 3 times in the two years or so I had it. The water resistance, or lack thereof, is a minor problem. I use it unprotected in moderate rain and after some time (some hours) you can get condensation forming on the internal optical elements. But it also dries out quickly afterwards. The question therefore is how much water are you likely to subject any lens to?
I recently also picked up the Sigma 120-300 OS. As far as I can see Sigma don't make any claims on water resistance on that either. I haven't really let it get wet yet, so I'm unsure how that performs. The internal zoom and focus means it does not have the extension which is the weak spot for water ingress of the 100-400L. In comparison though, it is a much heavier lens. Turning the zoom ring is much slower than the push-pull of the 100-400L. To my eyes, the image is slightly soft at f/2.8 and sharp at f/4 onwards. AF speed is comparable. No other image issues to report for now.
I haven't had a chance to try it with extenders yet, which is the main reason I got it, as I need more than 400mm with AF. I did not consider the 500mm class zoom lenses as they didn't offer enough over the 100-400L at the cost of their other problems. In particular I'd rule out the Tamron on the basis it has a backwards zoom ring and no HSM or VC.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.