IS off while mounting lens?

Turning off the camera does not remove power to the lens. You can check this yourself with a volt meter on the the camera's lens contacts.

With the camera turned off the lens will not AF or IS, but if you turn it off while the IS is running, it will continue to run.

Try it yourself if you don't believe me.

I never turn my camera off unless I'm traveling long distances and have it stored away. I have never turned it off while swapping lenses nor have I turned off IS before doing so. Never had a problem.

I thought the important bit with IS (of whatever flavour) was to ensure that the system had spun down, so that the moving elements lock themselves, before changing the lens.

Alan

If you don't flip the IS off (or VC or VR....this true for any brand) before unmounting, then the elements aren't locked down. You can check by lightly shaking an IS lens: you can hear the elements rattle slightly (and there are threads on the internet with people concerned about a rattling noise when they shake a lens). Personally, I don't worry about it. I'm not throwing my lenses. Since the elements are designed to have movement, I'll just keep IS on...can't see how regular use would damage it

msowsun wrote in post #17621326
Turning off the camera does not remove power to the lens. You can check this yourself with a volt meter on the the camera's lens contacts.

With the camera turned off the lens will not AF or IS, but if you turn it off while the IS is running, it will continue to run.

Try it yourself if you don't believe me.

Mike,

Are you saying it is possible to check the contacts of the lens while the lens is mounted to the camera? How is this possible?

It sounds like Mike is saying that even with the power off, there is power at the lens contacts on the mount. I am not surprised, given the activation of the light on the SD indicator when you insert a card, even with power off. I would guess that it would make sense to wait a few seconds for IS to power down after turning off the camera-before removing the IS lens.
Turning IS off on the lens would be a safe way to go, but that means you have to remember to do it. I have never done this. When changing lenses, I am usually in a hurry, since I want to minimize the time that the body is open and vulnerable to dust. Hurrying is probably not a good idea.

Inspeqtor wrote in post #17623463
Mike,

Are you saying it is possible to check the contacts of the lens while the lens is mounted to the camera? How is this possible?

I think he's suggesting checking the contacts on the camera body rather than the back of the lens

I have never turned anything off, nor the camera nor the IS - VC whatever the lens brand when swapping lenses.

davesrose wrote in post #17623448
If you don't flip the IS off (or VC or VR....this true for any brand) before unmounting, then the elements aren't locked down. You can check by lightly shaking an IS lens: you can hear the elements rattle slightly (and there are threads on the internet with people concerned about a rattling noise when they shake a lens). Personally, I don't worry about it. I'm not throwing my lenses. Since the elements are designed to have movement, I'll just keep IS on...can't see how regular use would damage it

Actually, that's wrong. If you are actively holding the AF on the lens, it's not locked down. Once you let go of AF for a few seconds, usually < 2s, the IS will power off and return to it's locked home position. The slight rattle is normal, it IS the locked position. When unlocked, it's a LOT sloshier. Try holding the AF with IS on and quickly spin off the lens - you'll notice that the IS unit has 3x more movement than the little rattling noise.

docholliday_sc001 wrote in post #17623611
Actually, that's wrong. If you are actively holding the AF on the lens, it's not locked down. Once you let go of AF for a few seconds, usually < 2s, the IS will power off and return to it's locked home position. The slight rattle is normal, it IS the locked position. When unlocked, it's a LOT sloshier. Try holding the AF with IS on and quickly spin off the lens - you'll notice that the IS unit has 3x more movement than the little rattling noise.

Actually, I don't think so. Unmount a lens with IS on and shake it. Unmount a lens with IS off and shake it. There's less of a rattle if IS has been set to off. Just google Nikon lens rattle and see how many posts are people being self conscious of a rattle (how I found this out was a coworker of mine shooting Nikon was a little perplexed by one of his lenses rattling). Most all responses are that with VR lenses, there's some rattle with VR on. I've found the same is with Canon. There may be more movement if you have unmounted with AF lock and IS on (assume the elements are completely dissengaged as the electronics are trying to compensate), but just leaving the IS switch on does not completely lock the elements in place.

docholliday_sc001 wrote in post #17623611
When unlocked, it's a LOT sloshier. Try holding the AF with IS on and quickly spin off the lens - you'll notice that the IS unit has 3x more movement than the little rattling noise.

Do you suppose that that's exactly why Canon said not to do it in the manual?

I could see why Canon would state not to unmount a lens while shooting for a number of different reasons Lens elements completely floating around with IS, potentially aperture or metering data being locked up...well at least normal operation of a lens shouldn't lead to any damage (or leaving IS on or off).

davesrose wrote in post #17623647
Actually, I don't think so. Unmount a lens with IS on and shake it. Unmount a lens with IS off and shake it. There's less of a rattle if IS has been set to off. Just google Nikon lens rattle and see how many posts are people being self conscious of a rattle (how I found this out was a coworker of mine shooting Nikon was a little perplexed by one of his lenses rattling). Most all responses are that with VR lenses, there's some rattle with VR on. I've found the same is with Canon. There may be more movement if you have unmounted with AF lock and IS on (assume the elements are completely dissengaged as the electronics are trying to compensate), but just leaving the IS switch on does not completely lock the elements in place.

Yes, it is so. If you don't let the 100L IS idle down for 2~3 seconds before dismounting, it'll sound like a marble in a Ball jar. It's why Canon says to wait before dismounting, and why you have to put it back on, and wait for it to lock if you remove the lens in a hurry. As long as the lens is ON - powered by the camera, it won't shake. When it is in the unlocked mode, but WITHOUT POWER, it'll rattle like hell. Been there, done it too many times while switching out the macro in a hurry.

PhotosGuy wrote in post #17623659
Do you suppose that that's exactly why Canon said not to do it in the manual?

Exactly.

davesrose wrote in post #17623664
I could see why Canon would state not to unmount a lens while shooting for a number of different reasons Lens elements completely floating around with IS, potentially aperture or metering data being locked up...well at least normal operation of a lens shouldn't lead to any damage (or leaving IS on or off).

When the IS is ON, it provides a dampening field to keep the floating IS unit from smacking the mounts. When it has not been "home positioned" before removing power (not powering off, but abruptly or prematurely removing power from the lens), it is outside that position and floats loosely without dampening.

Canon actually says in the manual (and it's perfectly accurate):
"The image stabilizer operates for about 2 seconds even when your finger is off the shutter button. Do not remove the lens while the stabilizer is in operation. This will cause a malfunction.".

Some lenses are more noticable when this happens, the 100L IS is one of them. The least noticable for me was the 70-200/2.8 L IS II. Yet, with the latter, it will make a VERY noticable CLUNK/CLACK inside the barrel.

All you have to do if this happens is remount the lens, half tap the shutter, wait for a few seconds, and dismount again so that it can home the IS unit and lock down.