but I could not figure out how to download a video I made on the same memory card, not to Aperture which of course does not accept video but to my computer.
Aperture does import movies from your memory card, if you do nor disable it in the "Import" settings:
In the "File Types" brick of the "Import" setting make sure that "Exclude videos" is unchecked, and the "Raw&Jpeg" setting should be set to "Both".
I turned off Aperture and then searched in my computer but the camera was not recognized anywhere in my Mac Book.
Probably you dismounted the camera, when you finished importing into Aperture. You could try to unplug it and reconnect it, and then check, if iMovie will recognize the camera.
The Canon G-15 is listed as compatible in the list of video-formats supported by Aperture, have a look: http://support.apple.com/kb/HT4025?viewlocale=en_US&locale=en_US
HI Leonie ..
I think the problem was that I had not yet "opened" IMovie ... since I have never used in on my Mac Air yet.
I found it in Applications and put it on the dock and then opened it ... and then I could see Aperture, etc. and at this point I could import the video I made (obviously the USB cable was still plugged in between my computer and the camera).
It will take me a while to get used to all of the possibiliteis of IMovie ... but I think I can probably manage it now. I may go to UTube for some instructional videos.
Thanks so much again for assisting. I leave tomorrow for a trip and now I can record videos and download them to the Mac Air.
All the best, Don