184 Better Available Light Digital Photography
What’s behind door no. 1
Before you open the door to RAW nirvana, it’s nice to have
some idea of what’s on the other side. When translating RAW-
image fi les, you’re going to have to deal with some technical
decisions such as bit depth and color space. If you’re not always
familiar with these terms, this chapter provides some background
to help you make decisions about what’s best for your
photographs.The simplest answer to “How many bits is enough?” is: The
more bits you have, the higher quality you’ll get. Think of the
decision as another version of one facing fi lm photographers. If
a landscape image made with 35 mm fi lm looks great, it will
look even better on 4 × 5 sheet fi lm and even better than when
shot with an 8 × 10 view camera. Capturing these larger fi lm
images isn’t easy. You can hardly pack an 8 × 10 view camera
in the same case as a professional digital SLR. Also, as the
physical demands increase, so does the cost of processing these
large fi lm images. Not only that, but storage becomes an issue
too. Get the picture?Big digital capture fi les equal more issues. The secret in
making it all work is to fi nd a balance between image size and
quality—a balance that fi ts your workfl ow and expecta-
tions. Hey, did I mention cost, too? Much as an 8 × 10 Sinar
view camera costs more than a 35 mm SLR, the digital
tools needed to work on large image fi les are gonna cost you
more, too.The upside of working with 16-bit images is theoretically
better image quality. I say theoretically better because it’s
still up to you to capture a properly exposed and sharp
image. The oft-heard quip, “Just shoot it—I’ll fi x it later in
Photoshop” doesn’t work if you are striving for maximum
image quality. Because you start with a larger image fi le,
there is less image degradation that can be created by the
inevitable rounding errors that occur when a fi le is processed
in an image-editing program such as Adobe Photoshop.
Image manipulation using 16-bit techniques also takes advan-
tage of Photoshop’s fl oating-point operations (that’s the math
that happens inside the program; which is why there can
be rounding errors), which produce smoother histograms and
tonal transitions.The downside of working in 16-bit mode is that fewer tools,
especially third-party plug-ins or “power tools,” are available to
work in that mode. Then there is the “Hulk” factor: bigger fi les
take more space and demand more computing resources. That
bargain computer you bought at Crazy Charlie’s Flea Market