Dng - Canon Camera Hackers Manual

48
C H A P T E R 4
The RAW Exceptions Menu. Not every
situation requires RAW output,
especially if you need faster camera
operation and more capacity for
images on your memory card.
Teach Your Camera New Tricks
RAW processor can be a 16-bit lossless TIFF file instead of a lossy JPEG file
that is restricted to 8-bit color depth.
Of course, there are good reasons for shooting JPEG, too. Because JPEG
files are much smaller than RAW files, they can be stored faster on the
memory card, resulting in faster operation when shooting a series—and, of
course, in higher capacity on your card. Also, you may not always want to
go through the time-consuming process of developing RAW files.
CHDK gives you the best of both worlds. When shooting RAW, the CHDK
Figure 4-35
also stores a JPEG version of the same image for preview. If you are happy
with the JPEG image, you can throw away the RAW file. If you think the
image requires some tweaking, keep the RAW file. CHDK even allows you
to exclude some situations from RAW shooting
eters > Exceptions):
Disable RAW @ Burst. Burst mode is faster when not shooting RAW.
f
There is also an option in the main RAW menu
very first shot of a series as RAW but the following shots as JPEGs.
Disable RAW @ Timer. You may not want to shoot your self-portraits in
f
RAW mode.
Disable RAW @ EdgerOverlay. Edge Overlay is typically used with shoot-
f
ing stereo and panoramic images. As many panorama stitcher and ste-
reo programs don't accept RAW files, JPEG is the preferred option here.
Disable RAW @ Auto Mode. You probably have your camera switched to
f
Auto Mode for casual shots. You would hardly need RAW images here.
For more serious shots where the RAW format makes sense, you would
switch your camera to Manual Mode because it gives you more control.
Warn when Exception? Optionally, a warning can be displayed when
f
one of the above situations applies.

4.5.2 DNG

The RAW format produced by the CHDK has some restrictions. First, CHDK's
RAW images are not equipped with EXIF data. Second, the RAW format
produced by the CHDK is not understood by all RAW converters. Some
simply refuse to open the image. A good choice is the program RawThera-
pee, which is available for the main PC platforms (Windows, Linux, Mac) on
a donation basis. It's a bit slow but delivers excellent results. Also, the free
command line tool dcraw converts CHDK RAW files with excellent quality.
Newer versions of the CHDK, however, can produce RAW images that
are already converted to the DNG format. Adobe Systems introduced DNG
in order to bring different RAW formats (each manufacturer has at least
one) under one umbrella. DNG files still contain RAW data but in a manu-
facturer-independent, Adobe-specific way. Some premium cameras such
(ALT > MENU > RAW Param-
(Figure 4-33) to shoot the