Submitted by Al …
(Adapted from The Encyclopedia of Photography ©1963)
Arriflex cameras are motion picture cameras made in both 16mm and 35mm models mainly for professional use. The principal feature of these cameras is their focusing system which enables the image to be both framed and focused directly through the lens while the subject is being filmed.
This is accomplished by placing the revolving shutter on an axis at 45 degrees to the lens axis and by having a mirror on the front surface of the shutter blade. Thus, when the shutter blade is in front of the lens, the light is reflected sideways to a ground glass screen on which the image is formed. A second prism and a lens system behind this screen carry the image to an eyepiece at the rear of the camera. The ground glass is exactly the size of the picture aperture in the camera. It is placed at the correct distance so that when the image is in focus on the ground glass, it will also be in focus at the film plane, just as in reflex cameras used for still photography.
There is no loss of light involved in this system because the image is reflected sideways to the viewing system only when the shutter is closed while the film is being pulled down for the next exposure. When the shutter is open for exposure, there is no image on the ground glass. This occurs 24-times per second during filming and the only drawback is some flicker in the viewed image.
Comments