External viewfinder system with 45° mirror and ground glass, mounted between camera and lens. Developed 1948 by SOM Berthiot; displays laterally correct but inverted image without parallax error.
Technical Details
The Vizelex setup consists of a mirror housing with a 45° surface mirror (typically 25-35mm in diameter), a ground glass in the format of the film size used, and a loupe system with 2.5-4x magnification. For 35mm cameras, the ground glass measures exactly 24x18mm. The housing is mounted between the camera and the lens, extending the optical path by 38-42mm, which requires a correction of the focus setting by this amount. High-quality Vizelex systems feature interchangeable ground glasses with various reticles and swiveling mirrors for through-the-lens viewing shots.
History & Development
The Vizelex was developed in 1948 by the French company SOM Berthiot and first used for the Caméra Éclair 16. Further development by Angenieux from 1952 onwards brought more precise optics and more stable housings. In the 1960s, the Vizelex established itself as a standard viewfinder system for documentary cameras like the Arriflex 16ST. With the introduction of integrated single-lens reflex viewfinders in the 1970s (Arriflex 35BL, 1972), the external Vizelex system lost importance. Modern digital cameras use electronic viewfinders, making mechanical Vizelex systems obsolete.
Practical Use in Film
Documentary filmmakers like Richard Leacock used Vizelex systems in the early Cinéma Vérité productions of the 1960s for precise image composition during handheld shots. In feature films like "Jules et Jim" (1962), the Vizelex allowed for spontaneous camera work in confined spaces. The main advantage lies in exact image control without parallax error, the disadvantage in light reduction by about one f-stop and mechanical susceptibility with intensive use.
Comparison & Alternatives
Unlike a prism viewfinder, the Vizelex shows a laterally correct but upside-down image. Modern successors are video assist systems and electronic viewfinders (EVF), which additionally provide exposure and color information. While the Vizelex operates purely optically, digital alternatives offer recording, magnification, and image analysis tools. For vintage cameras, the Vizelex remains the authentic solution; for contemporary productions, monitor systems are more practical and versatile.