Well I'm going to get my M3 in the mail soon and I dont have my SD card reader and the 2gb SD card bought yet. I was wondering if I can use my digi cam as a card reader to drop files in there for my M3?
Like seja said, in your camera, try to look for a setting to change connect mode from CAMERA to REMOVABLE DRIVE. Once it's on Removable Drive, you'll have no problem.
I would suggest that you only use your camera as a temporary card reader until you get a real SD card reader. I don't like the idea of using a $300+ camera as a card reader, but that's just me.
Not all, it depends on the camera. My Canon doesn't show the camera as a removable drive. I can transfer pictures to the computer, but it doesn't allow me to transfer anything to the camera.
Most cameras from the past few years do allow you to read and write to the media.
It works but it drains the battery out of your camera. One time I left my camera on and the battery was depleted. The transfering speeds are really slow too.