1 The Director of Photography – an overview

44 Practical Cinematography
A B C D E F G H
Shutter
OPEN
Figure 4.6 The claw and register
pin cycle
Shutter
CLOSED
Shutter
CLOSED
Shutter
CLOSED
Shutter
OPEN
Shutter
OPEN
Shutter
OPEN
Shutter
CLOSED
as the cameras lens. This is known as parallax error, as the optical axis
of the taking lens and that of the viewfinder will point in the same
direction but will run parallel to each other. This problem was first
overcome when a German company, Arnold & Richter, introduced
their Arriflex 35 mirror reflex camera to the world at the 1937 Leipzig
Fair. This camera totally revolutionized the way film cameras were
designed from then on.
The Arriflex did not have its shutter running flat to, and in the same
plane as, the film gate but had it angled at 45° to the gate and the aperture.
Furthermore, the front surface of the shutter had a mirrored surface,
so that when the shutter was closed the light that was blocked from
the aperture was now sent off at a right angle. This image was then displayed
on a ground glass whose distance from the lens, via the mirrored
shutter, was exactly the same as the film aperture.A second fixed mirror,
or prism, then sent the image on the ground glass to the viewfinder
optics.Thus, the image in the viewfinder was identical to that on the film,
as they shared the light from the lens on an alternating basis.
The original Arriflex was organized so that the mirrored shutter
sent the light horizontally to the viewfinder. Today, cameras divide
between those that send it horizontally and those that have the
shutter beneath the lens and send it upwards to the viewfinder.
Interestingly, Arriflex have made cameras with both configurations.
Figure 4.7 shows the arrangement of a reflex viewfinder where the
light is sent upwards.