I know there already is a key (Home) for cycling through the various camera modes but that can be pretty clumsy, especially if you're getting attacked. I like to use free camera mode while exploring and scavenging (useful for looking over your shoulder too). But in combat direct camera mode is preferred. But when someone starts beating on you it's kind of hard to switch to combat mode, start defending yourself, and cycle through the camera modes, usually going past it a few times.
Alternatively, allow us to set default camera modes for in and out of combat.