RAW-image-file capture 183Basically, the choice is between JPEG mode and camera RAW
mode, with several overlapping options thrown in. The option
to shoot in TIFF format remains for some models and more-
modern cameras even let photographers set their cameras to
capture both RAW and JPEG images at the same time. Remem-
ber, we didn’t say this was going to be easy.
JPEG is an acronym for the Joint Photographic Experts Group, the
name of the committee that created the standards in 1986 for still-
image compression. According to wikipedia.org, “JPEG itself
specifi es both the codec, which defi nes how an image is com-
pressed into a stream of bytes and decompressed back into an
image, and the fi le format used to contain that stream.” Your
camera makes adjustments to maximize the data, eliminating
colors the eye can’t see, and then compresses the image with a
reduced color depth to save the fi le in JPEG format. Because this
process discards what it decides is redundant data, JPEG is referred
to as a lossy (not lousy) format. Keep in mind, however, that when
the fi le is opened in a computer, the lost data is for the most part
rebuilt, especially if a low compression ratio was used.
Unlike JPEG, RAW is a format that requires little or no internal
processing applied by the camera. These fi les also contain 16-bit
color information, which provides more data, but that data now
requires external processing. When choosing the RAW setting,
all of the raw data from the camera’s imager is saved without
any kind of processing. Effects such as Contrast, Saturation, and
Sharpness are not applied to the image fi le.
Perhaps these food analogies will help explain the difference
between a RAW capture and a compressed (JPEG) capture:
- Cake. You can purchase a ready-to-eat cake in the bakery depart-
ment of most grocery stores or you can make one at home from
scratch. The store-bought cake is like the JPEG, because most
choices are made for you. The bakery decides what ingredients
to add, in what quantity, to meet their standards. You take it as is.
JPEG photographs are processed in-camera, compressed. You
take it as is. On the other hand, the made-from-scratch cake
allows you to choose the ingredients, altering here and there to
suit your personal taste. The same thing goes for the RAW
images. You decide in postproduction. - Chocolate-chip cookies. Off-the-shelf Brand X, Y, or Z. The
chips are already baked into each one, the softness of the
cookie is predetermined, and all are uniform in size. This is
the JPEG version. Baked at home with almost any recipe
gives you these choices: type of chocolate (semisweet, dark,
or white), the number of chips to fold into the batter, and
the size and shape of the cookies baked. This is the RAW
version. Now I’m hungry—Joe.