Indexer System Guide
October 2004
© As-Built Solutions Ltd
Page
8
2.6 Controlling Exposure
2.6.1 ISO
This is the electronic equivalent of film speed and indicates the sensitivity to light. For normal situations
a speed of ISO 100 should be used as this results in the minimum noise amplification.
In darker environments ISO 100 may result in unacceptably long shutter speeds, e.g. in excess of a few
seconds.
In this case increase ISO can be increased to ISO 200 or 400 with
minimal increases in noise on the images. In very extreme situations
the ISO can be boosted to ISO 1600 or even 3200 via the ISO
Expansion option on the shooting menu.
2.6.2 Aperture
In Av. mode the aperture is set using the small wheel.
To obtain sharp images the camera has been manually set up to
focus at approximately 1.5m. Other distances between 350mm and
infinity are kept in focus by using a small lens aperture.
2.6.3 Shutter Speed
In Av mode this will be determined by the camera. The Indexer is used on a tripod so long (> 1/20th
second) exposures are not an issue. However the Indexer will time out if exposures exceed 30seconds.
2.7 White Balance
The colour temperature of the ambient light will affect the colours reproduced by the camera. A cool light
such as florescent tubes will produce bluer colours then a warmer light such as a tungsten bulb.
Generally automatic colour balance will produce the optimum results
for any given image. However when viewed as a panorama the
uniform colour of a surface such as a wall will be affected if there are
different sources of light. If colour accuracy and uniformity is critical
a grey card should be used as a reference image as explained on p52
of the Canon manual.
