1 The Director of Photography – an overview

The motion picture camera 45
Figure 4.7 The mirror reflex
viewfinder
Objective
Lens
Fibre Optic
Focusing Screen
Light
Path
Mirror
Shutter
Viewing screens
The ground glass viewing screens of the early reflex cameras have now
been replaced with a slice of an end-on bunch of fibre-optics cut, and
ground flat, to produce a focusing screen. This greatly reduces
vignetting at the edges of the image, is much more critical of exact
focus so that the camera operator can determine the focus more easily,
forms an image far brighter than a ground glass and has less brightness
fall-off in the corners of the frame.
There is a very reliable way of setting your eyepiece to your natural
vision. Point the camera at an object less than six feet, or two metres,
away, and now rack the lens to infinity – use a lens of at least the
‘normal’ focal length and focus the viewfinder ocular on the cross in
the middle of the viewfinder, if there isn’t a cross focus on the line
around the viewfinder mask. Now refocus on the scene and you will be
able to eye focus perfectly.
The film magazine
Mirror
Film
Gate
Viewfinder
Optics
In order to be able to change from one roll of film to another at any
time, both the feed roll of film and the take-up roll are housed in a
light-tight container provided with a light trap, through which the film
can exit and re-enter the box – this assembly is known as the film
magazine.
Two configurations of magazine are common today. The first is the
displacement magazine, where both rolls are held in a single chamber,
as shown in Figure 4.8.The displacement magazine takes advantage of
Eye