On the other hand if you update the camera per frame you'll end up with the shotgun bug in Deus Ex: The Fall when running with vsync turned off (see Total Biscu

On the other hand if you update the camera per frame you'll end up with the shotgun bug in Deus Ex: The Fall when running with vsync turned off (see Total Biscuit's video on the game as an example for all sorts of bugs that exist because of timing issues from updating stuff per frame - note that TB didn't realize that). If you want to follow a character in a fancy way (ie. not locked), update the camera's target position in fixed steps and perform smooth interpolation between the last position and the current position for the frames between the updates.