Canon Camera, Hackers Manual

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C H A P T E R 4 Teach Your Camera New Tricks
4.3.7 Flash
Most Canon compact cameras have rather limited flash functionality. My
SD1100, for example, supports the following modes:
Automatic, Off, and
On (in manual mode). Red-eye correction and a red-eye lamp can be
switched on, and in manual mode there is a Slow Sync option. However,
there is no way to control the flash power. This is unfortunate; it’s hard to
use the flash as a fill light.
Once again, the CHDK comes to the rescue with an override. There is an
option to enforce manual flash even when the camera is in automatic
mode, and the flash power can be controlled in three steps:
weak (0),
medium (1), and strong (2). When using the flash as a fill light, the medium
and weak settings can be especially useful. I certainly would like a more
fine-grained flash control with the option of controlling the flash power in
1/3 f-stops; but, you can’t have everything. The three flash power settings
of the CHDK are better than nothing. The strong setting comes in handy
Figure 4-24
This detail of a night shot shows
massive graininess in the top image.
This was caused by setting the sensor
speed to ISO 6400 (market) on a Canon
Digital Elph 1100 IS (Ixus 80 IS).
Exposure time was 1/20 sec, aperture
f/2.8 at 6.2 mm (equiv. 38 mm). The
image was shot hand-held as a DNG
image with Bad Pixel Removal. The
image at the bottom, in contrast, was
composed of the image shown at the
top and seven more similar images, all
shot hand-held. Registration and
averaging was performed with
PhotoAcute Studio . No other noise
reduction techniques were applied,
so there is still room for further
improvement.
Figure 4-25
The commands for controlling the
manual flash are reached through the
menu Extra Photo Operations . You’ll
find them at the end of the menu.