Can you damage a lens by dismounting it while DOF preview is engaged?

<p>I understand a way to "lock" an EF lens to a set aperture to use with manual extension tubes is to engage DOF preview on the body while the lens is mounted and set at a specific aperture, then dismounting the lens while the DOF button is held down. Can this damage the lens (or the body, for that matter)? I'm just a bit wary of dismounting the lens while the camera power is turned on.</p>

<p>Thanks for any help.</p>

<p>No, doing so won't damage your lens. Aperture will work normally next time you mount your lens to camera body.</p>

<p>The only instance Canon mentions when the lens shouldn't be removed is while the IS is on (which means for about 2 seconds after fully releasing the shutter button.)</p>

<p>Don't think that will be much different then removing a lens while the camera power is still on. Tons of folks do that everyday. But then tons of folks walk out their door to work but get ran over by a truck on the way too. When it is time, it is time.</p>

<p>You really turn the camera off, take the lens off, put another one on, and then turn the camera on again? You must have a lot of free time.</p>

<p>No harm done. I sometimes do that when I want to reverse mount a lens with an aperture I want - useful for macro. I simply set the aperture I want with the lens mounted normally, press DOF preview to set the aperture and then remove the lens while DOF is being pressed. Carrying a reverse mounting ring is easier than carrying a macro lens when I want to travel really light.</p>

<p>Cheers, Bob</p>

<p>Thanks a lot, guys. That's reassuring to know.</p>