I was given the source video files from a 5D which I need to edit down for the web. I see many people first run the files thru compressor for prores 1080p 30. If there are going to be small web only files - do I still need to do that? or is there another codec i should use?
This is no a DSLR question, it's an editing question.
Lucky for you i'm a seasoned editor...
The whole reason for transcoding to Prores (or whatever) is to have more RT performance.
Editing with native H264 (that is what the files are) is cumbersome.
But if you only have to do simple cutting without fx, and it works good enough for you, there is absolutely no reason to transcode first.
But if you have to do serious work on your clips, do transcode or you will spend more time cursing than editing.
Just try, see if you can live with it as it is. If not, transcode.