The prismatic focuser was inserted into the film gate, and allowed focusing at the film plane through the taking lens. Although useful for cinemicrophotography, animation and title work, its use is rather limited for normal filming as the film door and pressure pad are removed while focusing. The model shown here is compatible with Bolex H-16 cameras having a serial number lower than 100,401, or H-8 cameras lower than 97,801.
