Shooting Raw; Basics - Canon Camera Hackers Manual

46
C H A P T E R 4
The RAW menu adds functionality for
outputting RAW files. The first menu
item, Save RAW, allows you to toggle
quickly between RAW and non-RAW
Teach Your Camera New Tricks
press the
a manual focusing mode must be switched into that mode.
Like any other override, the subject distance setting can also be con-
trolled via a script that allows you to do amazing things, such as automated
focus stacking. We will discuss these techniques in section 5.7.2.
4.5
The RAW image format has so many advantages for the semi-professional
photographer that all cameras should offer it. However, this is not the case.
In particular, many compact cameras do not offer this option. To be able to
produce RAW images with consumer cameras was the main rationale be-
hind the development of the CHDK.

4.5.1 Basics

RAW images are nothing more than the unmodified sensor data produced
by the camera. JPEG images, in contrast, are the result of a development
process: the color temperature is estimated and applied, the image is
Figure 4-33
sharpened, noise is removed, and the contrast is compressed. Scenes with
stark contrast usually have some highlights clipped. So, the camera has al-
ready made some decisions for you.
A RAW image, on the other hand, allows postponing these decisions to
a later time. You don't have to decide on processing parameters before
shooting.
taking a picture. Instead, you can make these decisions at the post-process-
ing stage when the RAW image is developed on a PC (or even in the cam-
era). It is possible to play around and try different options in regard to
exposure, white balance, sharpening, and noise suppression.
Another big advantage of the RAW format is that you can decide which
color space to use for the image during the development process. When
shooting JPEG, the camera makes this selection for you—and most com-
pact cameras won't allow anything but the small sRGB color space. The
RAW format does not cast the RAW sensor data into any preset color space.
This decision is made later when the images are developed in a RAW con-
verter on a PC. Most PC-based RAW converters allow you to use the wider
AdobeRGB color space. Some even allow for a larger variety of color spaces,
such as ProPhotoRGB or eciRGBv2.
LEFT button once. When using focus overrides, cameras featuring

Shooting RAW