500f/4 IS on w/beanbag - image floats around - problem?

I have already posted suspect focusing on my new 500 f/4 lens, but now I noticed another anomoly. With the camera solidly resting on a bean bag, IS on, when I half-press the shutter to get focus, and hold for a bit, the image in the viewfinder slowly floats around. Easier way to see it is when taking shots using Liveview and 10 sec selftimer. After pressing the shutter button, and during the 10 second delay, the image displayed on the rear LCD floats back and forth, up and down, for the whole time until the shutter fires.

I understand two things 1) the Canon 500 f/4 manual says to turn IS off when on a tripod. 2) People are saying the manual is out of date, and with the current 500 f/4 lens, the IS can be, and should be, left on. My question: With this lens on a tripod or bean bag, and IS on, does the fact that the image floats around between focus and shutter firing mean this lens has a bad IS or is this normal?

IMHO, if Canon made a change in IS, they would have made a simple change in the manual.
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If the image floats up for about a second then stops then this is the normal behavior of the tripod-sensing IS. If it continuously floats around without stabilizing then there's something wrong.

The image floats for the entire 10 seconds during self-timer shots.

The-digital-picture.com says this about the 500mm f/4 lens.

IS (Image Stabilizer or Image Stabilization) allows the Canon EF 500mm f/4.0 L IS USM Lens to be handheld a full 2 stops lower than a 500mm non-IS lens. Keep in mind - IS does not help stop a moving subject, but it does amazing things for a moving camera/lens. With a super telephoto lens, image stabilization is even important with tripod use as wind and other destabilizing sources can add movement/vibration to your setup. Fortunately, the IS version on this lens is tripod-sensing. The Canon EF 500mm f/4.0 L IS USM Lens knows that a tripod is being used when vibrations go below a certain level. Keep IS turned on when mounting the 500 L on a tripod to take advantage of this secondary IS mode - reducing mirror slap, shutter and tripod vibrations.

fred vachss said:

If the image floats up for about a second then stops then this is the normal behavior of the tripod-sensing IS. If it continuously floats around without stabilizing then there's something wrong.

Click to expand...

Mine actually floats for a few seconds before stabilizing. If the photo taken is sharp, then you shouldn't worry about it.

In any case, if the subject allows you time to use a 10-sec timer, you should be better turning off IS anyway. This will allow you more precise framing, plus an IS-off shot with the mirror up (like in LV operation), and using a steady support, can be sharper at slower shutter speeds (1/50 sec or slower).

fred vachss said:

If the image floats up for about a second then stops then this is the normal behavior of the tripod-sensing IS. If it continuously floats around without stabilizing then there's something wrong.

Click to expand...

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Romy



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liquidstone said:

Mine actually floats for a few seconds before stabilizing. If the photo taken is sharp, then you shouldn't worry about it.

In any case, if the subject allows you time to use a 10-sec timer, you should be better turning off IS anyway. This will allow you more precise framing, plus an IS-off shot with the mirror up (like in LV operation), and using a steady support, can be sharper at slower shutter speeds (1/50 sec or slower).

Click to expand...

Romy is right about turning off IS if not needed.

I would also like to point out that a beanbag is NOT a tripod. So any mention of leaving IS on when on a tripod does not apply on a beanbag.

On a tripod you will get little vibrations. A beanbag is much more stable. So turn IS off when on a beanbag.

--
Ron

See some of my stuff at http://ronhodgson.net/ Not Dial-up friendly, so be patient.

That's normal behaviour Gus!

My 500 and 600 do the same thing when on a tripod.