in addition to the objective, the viewfinder consists of a 45-degree mirror (the reason for the word "reflex" in the name), a matte focusing screen at the top of the camera, and a pop-up hood surrounding it. the two objectives are connected, so that the focus shown on the focusing screen will be exactly the same as on the film. however, many inexpensive "pseudo" tlrs are fixed-focus models. most tlrs use leaf shutters with shutter speeds up to 1/500th sec with a b setting.