I believe that I read in Arthur Morris' book or on his website, that the information in the camera lens manual concerning IS lenses is incorrect--- That is when an IS lens is tripod mounted the IS function should be turned off (to "0" as opposed to "I") He states that it should be turned on (to "I") My own experience seems to show that this is correct. One would hope that by leaving the Image Stabilizer function on this would help compensate for any tripod movement at all. Any thoughts or experience with this, IS users?

-- Rose Bajorins (Bajorinr@viser.net), January 18, 2000

Answers

I've been using the 300/4 IS for some time now, and have had numerous occasions to experiment with this lens, tripod mounted (as well as when merely braced or resting on a more solid support, such as a fence or car window), with the IS switched in or out (just to see what happens); my preliminary observations in such circumstances suggest that the IS system functions quite well if one is frequently or continuously moving the lens even slightly, such as might occur when using a tripod more as a monopod. In addition, I found that the IS often works pretty well when the tripod is coarsely vibrating or bouncing, such as when one is set up near train tracks and a train rumbles by. Although I can't recall the exact details now, I have also tried engaging IS when the lens is tripod mounted and everything seems quite still; in this situation, when I activated the EOS 1n/300 IS combination by depressing the remote release half-way, the IS gyro's spun-up as usual, and continued to spin, but the IS may momentarily want to re-hunt the target if you bump, jar or slightly move the lens. I unfortunately can't recall if the IS system eventually spun down during such still conditions due to a lack of perceived motion on its part, but at any rate, I do recall that I eventually turned off the IS because it was spinning happily (you can hear it if the environment is quiet), and it was consuming battery power! Therefore, my preliminary, tentative conclusion is that the Image Stabilization function of the 300/4 IS is probably not useful and may even degrade the image when the camera and lens are perfectly or nearly still (and it is eating electrons!), but that it is often quite effective when the lens is on a more stable but still subtley moving "platform", as described above. I'm not familiar with the characteristics of the IS system in Canon's newest, big glass lenses, but I have certainly been quite impressed with the performance of the 300/4 IS.

-- kurt heintzelman (heintzelman.1@osu.edu), January 18, 2000.

Rose,

Canon is correct. you don't have to take my words for it, because you see it for yourself. on a tripod, center your subject on the central sensor, and depress the shutter release halfway, with IS on. you will hear the stabilization circuity activate, and if you watch carefully, you will see the subject slowly drift from your initial point. the IS circuitry doesn't latch onto anything at all, no target acquisition, but simply assists *your* movements to attempt to keep the subject centered. if it cannot detect movement, as on a tripod, it simply wanders aimlessly, slow dancing to noise, rotation of the earth, with a mind of its own.

the rule is, if you cannot control the aiming of the lens and introduce corrections to keep the subject on the same point in the viewfinder, turn IS off.

-- Daniel Taylor (aviator@agalis.net), January 18, 2000.

The "drifting" certainly happens with the 300/4L IS. I haven't yet had a chance to use one of the new IS lenses (300/2.8, 400/2.8. 500/4, 600/4), but the Canon literature on them suggests that they "know" when they are mounted on a tripod (I presume if they feel no motion, they assume they are on a tripod) and the IS function can be left on. The 100-400IS is, I guess, an "older generation" IS and so might need to be turned off when tripod mounted.

-- Bob Atkins (bobatkins@hotmail.com), January 18, 2000.

At the Venice Rookery last week the wind was blowing quite hard and steady. Using my 100-400 IS lens on the Gitzo there was a definite problem with shakiness ala wind. I decided to turn on the IS and WOW!! The unit acted like a giant vise came in and stopped all motion. Got the slides back and just as sharp as if it had been no wind. Some guys on either side of me were using big Nikkors and wanted to try out my setup. Needless to say they were impressed and one was ready to dump his Nikon stuff right there. Just wish he could see the images. My flight shots using a 1.4X were impressive too and the wind effect was nullified hand-holding the lens and EOS 3 with available AF to boot.

-- Jeff Hallett (franjeff@alltel.net), January 22, 2000.

Whether you should turn the 100-400 IS on or off on a tripod depends on your technique. If your technique is poor, or the day is windy, leave the IS on, and it will sense your minute vibrations and correct them magnificently. If your technique is really good, and the lens is absolutely still, that ugly IS wander comes into play, the view drifts around, and that drift will show up as out-of-focus slides that look like you had handheld 400 at 1/4 sec. Apparently this is fixed in the new 300/2.8 etc big lenses, but I doubt that I'll be trying any of them soon to actually test it.

In the meantime what I do when the 100-400 is on a tripod: if there is absolute stillness that I can be sure of, then the IS goes off; if I am sort-of-handholding on a loose ball head, or touching up focus now and then, then I use the IS. If the IS is on and I notice it drifting because now I am TOO still, then a very slight movement of the hands (almost unnoticeably slight) is enough to get the IS working as it should again.

-- Les Gyug (Les_Gyug@bc.sympatico.ca), January 25, 2000.

Les is absolutly correct. Technique and the ability to sense the "drifting" is crucial to getting sharp slides. The IS really has saved the day for me in several tripod and non tripod mounted situation.

-- Jeff Hallett (franjeff@alltel.net), January 26, 2000.