100-400 IS on tripod. Turn IS off?

sharpness and even the focus point are damaged.

MHO `pigs trallop` instruction manuals clearly state on earlier IS lenses do not use with tripodss , new have 2 modes, How does the focal point get damaged. Does that mean oops I left IS on the 28-135 on with the 20D. ah its ok got 8 focal points left.

please explain before I destroy my DSLR `s focus facilities.

I have a 100-400 IS L. It is an earlier IS design (I think it was Canon's 2nd or 3rd IS lens). The instruction manual states that IS should not be used when mounted on a tripod. I have left it on accidentally a couple times while on a tripod, and the resulting image is slightly blurry, or looks a bit like a double image. I'm not sure the exact mechanics of it, but I can even see the effect through the viewfinder if I'm paying attention. If I mount it to a heavy stable tripod, when I partly depress the shutter and the IS engages, I can see the image shifting and torqueing in the viewfinder as it attempts to compensate for movement that doesn't exist.

I don't know which other IS lenses work like this. I know the newer telephoto prime lenses with IS are designed somewhat differently, and don't need to be turned off while tripod mounted. Not sure about the 70-200 IS, which is also a newer design than the 100-400 IS.

Unfortunately, you can't always trust Canon's manuals; they famously made a mistake in exactly this regard on the IS superteles (300/2.8 through 600/4). Canon announced that the IS in these lenses has a new tripod mode. Then they printed a bunch of manuals saying that IS had to be turned off when they're used on a tripod. The press release was right; the manual was wrong.

Back to the question at hand. The 100-400 was Canon's fourth IS lens and uses the second IS generation, which does not have tripod mode. The issue isn't a tripod per se; it's whether there is any motion. Even a small amount of motion will keep IS happy, so if you're shooting on a particularly flimsy tripod, or even with a solid tripod but on a windy day, you should be able to see motion when you look through the viewfinder, and if so, you can leave IS on. If there's no motion at all, turn IS off, as the first and second generations will actually introduce motion if the lens is perfectly still.

Undesired motion will damage sharpness, obviously, if the shutter speed is not high enough to cancel it. There is no damage to focus points; I'd be interested in hearing your friend explain exactly what damage was done to the focus point.

Quick summary of generations:

1. 75-300 and 28-135. Not to be used while panning; no tripod mode; takes approxiamtely 1 second to stabilize; effective for about 2 stops
2. 300/4 and 100-400. Adds mode 2 (panning); otherwise, same as first generation.
3. IS superteles (300/2.8, 400/2.8, 500/4, 600/4); I think the 400/4 DO also has this version but I'm not 100% sure and I'm too lazy to look it up. Adds tripod mode.
4. 70-200 and subsequent models (28-300, 70-300). Adds quicker startup (0.5s) and effective for about 3 stops.

P.S. to Yakim, aren't you going to tell him to ditch his zoom and buy a nice set of primes? :-)

Here you go Yakim, from Chuck Westfall. (I think this is what Chris JB was trying to say.)

The following EF Image Stabilizer lenses support "Tripod IS":

EF28-300mm f/3.5-5.6L IS USM

EF70-200mm f/2.8L IS USM

EF70-300mm f/4.5-5.6 DO IS USM

EF300mm f/2.8L IS USM

EF400mm f/2.8L IS USM

EF400mm f/4 DO IS USM

EF500mm f/4L IS USM

EF600mm f/4L IS USM

The following EF Image Stabilizer lenses do not support "Tripod IS":

EF28-135mm f/3.5-5.6 IS USM

EF75-300mm f/4-5.6 IS USM

EF100-400mm f/4.5-5.6L IS USM

EF300mm f/4L IS USM

-------------------- Chuck Westfall Director/Media & Customer Relationship Camera Division/Canon U.S.A., Inc.

Once I compared it while shooting the moon. The shutter was set at 1/200. The tripod: Bogen 3021 wiht 3047. When IS was turned on, it took about 2-3 seconds to get the image stable, from the viewfinder. The pictures were absolutely sharper than those IS was off. If only waiting for 1 second, the picutres were soooooo soft. I think the trick is to wait for enough time to get the image stablized.

With my 100-400L, I use the IS if I'm maneuvering the lens on a tripod with the ballhead loosened, and shoot. Even locking down the ballhead, the 100-400L seems to benefit from IS for awhile, but after a few minutes, it "goes crazy" and I hear thelens make a knocking sound. When this happens, I turn off the IS for a minute or two, and turn it back on.

I also have used a 300/4L IS, and it had no tolerance at all for the IS being turned on while locked down, though it was content to have IS on with the ballhead loose. But the moment I locked the head down, image quality would go to blazes (without the knocking sound of the 100-400L as a warning--I lost some neat shots that way first time it happened....).

Forgot to say that I was using 100-400 and a cable release. With IS on and on tripod, no any trouble with the focus point. Actually even with a Tamron 1.4x, I can still get the autofocus while IS on and on a tripod. (Never count on it. The autofocus speed is a snail.)

"However, a friend of mine who has it and claims that with IS, sharpness and even the focus point are damaged. He used MLU and a cable release."

If he uses MLU, I don't think IS is affecting either his sharpness or focus point. In MLU mode, IS is switched of by the camera.

Steve pretty much summed it up. The stabilizer system compensates for motion by "floating" some of the elements in the opposite direction of dectected movement. If there is no movement, the IS system introduces it. However, there are no hard and fast rules. :)

From the latest Canon lens brochure (that I know about, available on their website): "Optical shake is detected by gyro sensors which provide the data necessary to shift the image-stabilizing lens group in parallel to neutralize the shake. This increases the usable shutter speed range by up to 2 full steps for hand-held shooting. Except for the EF 28-135mm f/3.5-5.6 IS USM and EF 75-300mm f/4-5.6 IS USM lenses, IS lenses have two IS modes. One is for normal image stabilization and the other is for panned shots. With a monopod, the Image Stabilizer on all IS lenses operates normally as during hand-held shooting. Also, the EF 300mm f/2.8L IS USM, EF 400mm f/2.8L IS USM, EF 500mm f/4L IS USM, and EF 600mm f/4L IS USM lenses have a mechanism that prevents having the Image Stabilizer turned on while the lens is mounted on a tripod."

As you might notice from that excerpt, I think the list Frank posted is incorrect (especially since I've seen the mode switch on a 100-400). Mode 1 is for normal hand-held operation. Mode 2 is for panning, and (I would assume) disables one (the vertical or horizontal depending on orentation) set of gyros. The last line about IS being disabled if it detects being mounted on a tripod is something I'm not sure about, as it hasn't been my experience. Maybe it's just *really* sensative about detecting any movement at all, so you have to have a rock solid tripod and use a cable release and have no outside influences (ie wind) on the lens for it to disable itself.

From the manual to my 70-200: "...Mode 1 corrects all vibrations no matter whether the camera is being held horizontally, vertically, or at an angle. ...Mode 2 corrects vibrations and shaking only in the direction at right angles to the camera's panning movement. ...Set the [IS] switch to OFF when you are taking pictures with a tripod.* - Even if the [IS] switch is set to ON, the IS function does not operate because the electronic circuits in the lens automatically detect that a tripod is being used. However, electrical power is still being supplied to the [IS] unit, and battery life is roughly 20% shorter than it would be with the switch set to OFF."

*I think this is the manual error being refered to - the manual basically says even mode 2 is only for hand held, and you should always turn IS off when on a tripod, which isn't the case. Now that's what the literature says. In my experience, I have noted the following.

With the first gen (75-300) they say you can't pan with IS on. You can - you just have to take the shot before you stop moving the camera. The IS movements are much more pronounced in the first gen system, and if you pan with it you will see the view go nuts when you stop movement. However it's pretty stable up until you stop as long as you move in one direction only. As for mounting it on a tripod, forget it. It's so light and the IS so heavy-handed that it overcompensates even if there *is* any movement about 90% of the time. I have more than ten years with this lens, so I'm pretty comfortable with what I can do with it.

I've only had the 70-200 a couple of months now, so I'm still learning the nuances. From what I've seen, mode 1 works for hand-held panning shots. I haven't played much with mode 2. With the tripod mounted shooting I've done, it's apparent that a) I need a heavier tripod because it still vibrates for a bit after moving it/depressing the shutter and b) sometimes IS improves it but mostly it degrades image quality. I haven't done a lot of testing with that though, nothing in really significant wind or at slower shutter speeds.

The short answer is I would do some experimenting in the kinds of shooting situations you're usually in. Shoot a few frames with it off, then a few with it in mode 1, then some in mode 2. Do a broad enough sample that IS comes into play, and not just focusing. Make a note of which are which frames as you shoot, then compare them. Hopefully you'd see an overall pattern that suggests what you should set it to.

And I don't get the damage to focus points thing either.