iMovie may have converted it to a different format, such as H.264. Locate one of the iPhoto videos in Finder, then open it with QuickTime (either QT X or QT 7). In the QT menu, select Window>Show Movie Inspector - what does it show against Format (including size)?
Do the same with the Event in iMovie. In Finder, go to your iMovie Events folder and open one of the Events imported from iPhoto. All the clips in the Event will probably be labelled with the .mov extension. Open a clip in QuickTime and check the format and size.
When highly compressed AVCHD clips are imported to iMovie they are converted to Apple Intermediate Codec (AIC). This effectively decompresses the clips, converting them to full frames for ease of editing. AIC uses about 40 GB per hour - about 4 times the size of AVCHD (.mts files).
Of course, your iPhone clips in iPhoto may already be H.264 (don't have an iPhone yet - hanging out for iPhone 5). But check the format for both the Event clips and the iPhoto clips - I may be way off-beam here!
Thank you both.
The iPHone records in a compressed h.264 codec that took up 7.2MB for the video and 3.2MB for the iphoto thumbnail when I imported it.
The same video, when I imported it into imovie, became 35.4 MB and, fortunately, the thumbnail remainded the same at 3.2MB. THe imovie imported the movie and converted it to a AIC ( Apple intermediate codec) which, as you all noted, is the format that can be edited.
SOOOOO, the problem now is that I have so many duplicates on the computer becuase after iMovie imports the video, it does not offer the option to delete the original...it copies the video ( and uncompresses it) it does not simply move it.
Any recommendations on how best to filter through all of these and find out how to get rid of them??