« on: May 18, 2014, 01:05:51 PM »
Theoretically, IS should help in those situations. But, I have done extensive testing with the Canon EF 35mm f/2 IS USM and found otherwise - and the 35 IS USM uses a very recent revision of IS, probably the same revision as the one in the 16-35 iS.
What I found was that though Canon's IS does work great on or above shutter speeds of 1/30 (such as with the 70-200), it is very unreliable below that. In fact, I found little to no improvement of my handheld "hit" ratio with very slow shutter speeds and the 35mm IS USM; sometimes IS completely failed to stabilize the shots, and often when it did it remained overly soft bordering on blurry - I did not see any real advantage to using it with 35mm and very slow shutter speeds, a monopod/tripod was night and day better and far more reliable for wide focal lengths and very slow shutter speeds. IS did have use for video and panning shots on the 35mm, though - it worked quite well in these areas. I assume the same limitations will hold true for the 16-35.
I have no experience with the 35mm f/2 IS but it sounds like the IS system may be faulty if you are not seeing any difference. You should be getting sharp shots at 1/8th at least. How slow did you go with your testing?
What image-stabilized wide angle Canon do you have experience with?
There is nothing wrong with the IS system, I use it for panning shots all the time.
I tested from 1/30 all the way down and in between to 1/2, as Canon claims the IS system had the equivalent of 4 stops stabilization - which would be around 1/2 for a 35mm. The bottom line was the the IS system was unreliable at 1/15, 1/8, and especially below that while the pics were usable, they were definitely blurry compared to a monopod and not much different than with IS disabled assuming halfway decent technique. This is different than with the 70-200 where the IS truly works as many stops as advertised.
I also noticed the same behavior with the 28mm IS when I had it, the IS simply is not as effective at very slow shutter speeds.
Yeah I agree that the stabilization effect is more noticeable with a 70-200 than with the wider focal lengths but with my 17-55 @ 17mm I was getting fairly sharp useable shots at 1/8th and that has an older version of IS. The 24-105 has pretty decent IS too. Even the old 18-55 kit lens did alright.
What I find is that while IS cannot truly replace a tripod or monopod it does reduce the amount of camera shake to the point where it is at least acceptable for web use. The shake is still there and likely most of it from the mirror which makes me wonder actually ... I know the 70-200 IS has an anti mirror slap vibration function, maybe the 35 doesn't have that so there is a limit to how effective it can be?