The only way to take a screenshot without your character present would be to indeed zoom in the camera into first-person perspective, which as I play on the PC version I'm unsure how to do that on the PS3 version via control pad.

However, the default key for the PC version to cycle between 1st and 3rd person views for keyboard control is the 'Home' key. Also if you want to remove all menu and interface overlays temporarily, press the 'Scroll Lock' key to hide them or bring them back.