ARRI WRC-1 - Manual (Page 11)

11
Speed ramps
Altering the camera speed also changes the film exposure
time. In order to hold the film exposure constant when
changing the camera speed, either the shutter angle of the
mirror shutter or the aperture of the lens must be adjusted
accordingly. The WRC-1 allows the camera speed to be
changed while simultaneously retaining a constant exposure.
Several different compensation methods can be selected.
Example: the camera ramps up from 24 fps to 48 fps.
Two compensation options are available:
Compensation fps Shutter Angle Aperture Result
None 24 180 5.6 OK
48 180 5.6 1 T-stop under-exposed
Shutter Angle 24 90 5.6 OK
48 180 5.6 OK
Aperture 24 180 5.6 OK
48 180 4 OK
The required compensation type can be simply selected
using the COMPENSATION rotary switch on the WRC-1.
The camera speed can either be adjusted using the
handwheel, or it can be pre-set by programming a speed
ramp, which is activated by pressing the RAMP button.
Note: Adjusting the iris alters the depth of field.
Adjusting the shutter angle, on the other hand,
does not alter the depth of field. A small shutter
angle and a rapid camera movement, or fast-
moving objects, may result in stroboscopic effects.
Adjusting the shutter angle when using HMI
light may result in inconsistent film exposure.
T
ypical Applications