Clean HDMI output

Everything a camera draws on its own screen normally travels down the HDMI cable too, which makes the output useless for anything downstream. A clean output strips the overlays, and that is what lets a camera work as a webcam, feed a stream, or record to an external device. Check the specification before buying if you plan to stream, because some bodies output clean only in certain modes, some drop to a lower resolution, and some cut the signal the moment recording starts. A capture card handles the conversion into a computer.