Powering down the camera for lens changes

I note Blackmagic recommend powering down the camera for each lens change.

Does anyone know what the basis for this recommendation is and what the likely scenario is for anyone who might forget?

Thanks

Jason

Apart from letting an extraordinary large amount of light into the sensor, you could short the electrical contact on the lens connection and fry your camera?

Forgot it once and the BMC froze. Had to reboot it and everything was fine.
I think this applies only to glass, that talks to the camera, not dumb manual lenses.

[Kristian Lam]

You won't fry the camera but there might be instances where communication with the lens may not be properly initiated. It's good practice to turn off the camera when changing lens.

Also since the camera starts up so quickly, there's really no fear of long delays should you power down the camera.

I flat out did not know this! I have changed lenses with this camera still turned on over a hundred times. No issues.

I will ,however, heed the advice going forward.

The powering up time is indeed very quick and isn't really the issue.

It's more that I work with other cameras on a day to day basis that you don't turn off for lens changes and at some point either I or my assistant are going to forget that the BMCC should be shut down.

It's good to know it won't fry the camera and thank you David for testing that so thoroughly!!

Jason

[Kristian Lam]

I flat out did not know this! I have changed lenses with this camera still turned on over a hundred times. No issues.

I will ,however, heed the advice going forward.

It's rare. I change it without turning off the camera as well.

I guess theres no real way to improve the EF connectors to re-detect a new lens whilst the camera is on, I'm used to changing lenses whilst the camera is on too, well... something to think about.

I have had strangeness with the lens after I change it hot.. re-boot fixes it.. but I really should power down when changing lenses

I had heard once that when the camera is on the sensor can attract particles so all lens changes should be done with camera off and pointed down.