A great tool that I personally work with is vvvv. A very mighty visual programming toolkit somewhat comparable to Quartz Composer on Mac but available for Windows (only for Windows for now but future versions might be multi plattform according to the devs).
For getting started I highly recommend this cheat sheet http://vvvv.org/sites/default/files/uploads/dontpanic_45beta25_1_0.pdf
Nice thing is that you can capture video over USB with a few canon DSRLs and don't necessarily need an HDMI capture card.
While you can capture frame with the "Writer" node, usually you would utilize Fraps for capturing the renderer (which can be lossless or in h264)