> Thanks for your reply.
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> The plug-in being used is Cerious Plug-in and then plug_digicam.tpp. I've tried changing to the other options (I am using Photoshop CS3) but no improvement, some of them much worse. I don't understand about "built-in preview images embedded in the DNG files." I do notice that my .CR2 files do display full screen making me think it has to do with the DNG files. Is there any solultion to this or should I just stop converting my CR2 files to DNG? I've had to switch to Adobe Bridge to view my DNG files in larger format.
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> Slideshow settings are set to full screen but it doesn't seem to want to work that way.
Raw files (such as CR2 and DNG) have preview images built into them so that photo viewing applications can display their contents quickly, without having to process all the raw sensor data that's inside these files and turning it into a viewable image (which can easily take 4-15 seconds per image).
So, an explanation for the behavior that you're seeing could have been that ThumbsPlus is using this preview image (rather than the full sensor data) for slideshows, and that the DNG files have smaller previews built in than the CR2 files. If that's not it, I don't know what else could be causing it. But then, raw files are not very suitable for slideshows to begin with, because of that long processing time. If you're one of those users who use the slideshow to view and cull images, I'd suggest using the regular viewer for those purposes instead. In the viewer, you can use Space and Backspace to move back and forth through your images.
Some people convert their original raw files into DNG thinking that the DNG format will be supported for much longer into the future than CR2 files. I doubt if that's true and personally, I'd never do anything to my original files that might lead to a loss of data or that may not be processed as well as my native raw files are by their native applications - in other words, I'd want to keep them in Canon's CR2 format and keep the option to use Canon's software to process them.