I am running Photoshop & Bridge CS2 and have recently upgraded from a Canon 20D to Canon 50D. Bridge & Protoshop will not open the RAW files. I have looked at previous discussion threads, and know that I need to update the Camera Raw plug-in, but I an not sure whether the latest Camera Raw plug-in is compatable with CS2 (the Adobe site keeps refering to CS4). Can the latest plug-ins be used with CS2?
Unfortunately not. You will have to either upgrade to CS4 or use the free standalone DNG converter.
The last version of the Camera Raw plug-in to work with CS2 is ACR 3.7.
You can, however, run the free, stand-alone Adobe DNGC Converter to convert raw files generated by cameras supported by the current ACR version to raw DNG files that can then be opened in ACR 3.7 hosted by CS2.
You always want to run the latest version of the Adobe DNG Converter, as it is totally independent from the version of ACR that works with CS2.
EDIT: JJ types faster—and more succintly—than I do.