In its default state (on), the camera will auto-zoom in at the feet of the leader when you move the camera to view upwards (i.e. up-skirt perspective). By turning it off, you can view the surrounding area from below the ground. This allows you to see hidden spike traps (e.g. Occulta Dungeon) as mentioned previously here. This can also be achieved by typing /camcol on or /camcol off in the chat window.
Hide Active Markers
By default (off), active characters have green markers at their feet to indicate that they are being selected. The leader's marker is a circle, while followers' markers are triangles. You may want to hide the markers when taking screenshots without using Alt-F.
To add the hot-keys for these commands, you must be using user-defined hot-keys. Simply open your hot-key file (.xml) with Notepad and add the following lines.
Thereafter, you can turn on these functions with Ctrl-F2/F3, and turn off with Ctrl-Shift-F2/F3.