Andrew Balis has posted a great article on Ken Stone's Final Cut Pro Web Site discussing the workflow of using different sources in Apple Color - the professional color grading application that's part of Apple Final Cut Studio 2.
One of the most confusing issues that comes up frequently with new users of Color is how to get in and out of Color with different types of video formats. Therefore, the purpose of this article is to clear up the confusion by presenting the four main workflows Color can utilize, as well as how each format can be handled by Color. This article relates to users of Color version 1.0.2 or later. We'll look at how to handle video formats captured via capture card, as well as how to work with "native" formats captured via FireWire such as DV, DVCPRO 50, DVCPRO HD and HDV.