Image Stabilization and Tripod

It's my understanding that the IS gyros depend on slight motion in order to keep the image stable. The 70-200 IS lens I just purchased actually states in its docs to turn the IS off as it will lead to a decreased picture quality (presumably due to the hunting effect you noticed).

My thought on the tripod wildlife photography, if your tripod is stabe enough and there is little to no wind, leave the IS off. An additional help for tripod photography is to utilize the mirrow lock-up function.

I also do a lot of wildlife photography with a tripod so should I be using IS with a tripod or turning it off?

Supposedly you should shut of IS on the 100-400 when using a tripod, but I often used this lens on a tripod and often forget to shut of IS when I do. Nonetheless, the pictures are sharp. It may depend on how steady the tripod is and how long an exposure you're making. On a big, solid tripod, I'd switch it off. Dunno about the 17-85 (I don't have that lens).

On my 28-135mm and 75-300mm IS lenses, you turn it off when mounted on a tripod. If let turned on, I get blurry pictures.

Only use IS on a tripod when panning (That is what the newer IS lenses support). If you are using it for fixed work, where you won't be panning the camera during the exposure, turn off IS.

If you are taking static shots with the tripod's controls locked, the tripod and head are heavy and solid, there is nothing shaking the earth (such as a passing train or automobiles or foot-traffick), and not enough wind to disturb the camera (in other words, if you can look through the viewfinder and not see any camera motion whatsoever), then by all means turn the IS off. Otherwise, leave it on.

You can use IS on a tripod, but not for long exposures. The range of shutter speeds at which IS is effective on a tripod is similar to the range at which it is effective hand-held.

IS on a tripod is especially useful in windy conditions.

I wasn't aware that the 100-400 had the newer type of IS. Mine didn't seem to, because I never found it very useful on a tripod. The IS on the super-teles definitely works very well on a tripod, in just about any conditions.

Another thread on this subject: http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00EPRj .

Although Canon says both in manuals and at http://www.cps.canon-europe.com/kb/detail.jsp?faqId=1130 , that IS can be left ON on a tripod, and in fact should even improve results, my experience with two 70-200 2.8 IS's is that IS will cause blur when on a stable tripod.

The movement that IS causes on a tripod is plainly visible through the viewfinder, and I think your tripod would have to be very rickety or it would have to be quite windy to warrant using IS on it.

Looking at my last post, I didnt' mean to imply my experience would duplicate on the 100-400 L IS. That lens mey behave differently.

It's easy to test. Take a series of longer exposure (1/2 - 1 sec) shots zoomed in on some detail, with and without IS, and compare results.

Also use a shutter remote to minimize movement.