The Canon EOS and Photography Forums

A speaker at a meeting of my local camera club warned against downloading images from the camera to a computer using a USB cable.  The risk is that due to static electricity the camera could be at a different potential to the computer.  The issue is that the computer is earthed and the camera is not.  Connecting the two via a cable could result is a static discharge that could damage the camera.  Has anyone experienced this problem?  I have not come across it before and this is  how I download all my images to my computer.  I also frequently connect my camera to my computer when I am converting my old film prints to digital format.  I mount the camera on a copy stand and control it from the computer using DPP and transferring images to the computer directly.
Ken

What qualifications did the speaker have and what evidence did he present to back up his theory?

The computer may or may not be grounded (or "earthed" in UK terminology). Anything running off a 2 pin plug can't be grounded, but if it has a 3 pin plug it can be (and usually would be).

We plug lots and lots of USB devices into PCs. printers, scanners, routers, modems, disk drives, iPods and cameras to name a few. If there was a chance of damaging any of them we'd have lots of complaints and the engineers who designed the systems would be out of a job.

Looks to me like a USB makes a chassis (ground) to chassis(ground) connection first, before any signal lines get connected anyway.

So I'd say the speaker didn't have a very well informed opinion. I don't think there is any danger connecting a camera to a PC due to  "static" issues.

Thanks Bob
The speaker  is well informed on matters photographic but offered no evidence for his concern about damaging the camera.  I shall continue to use a USB connection to download images. 
Ken