Instruction manual

14
B. RAW
Unlike JPEG and TIF, RAW is not an abbreviation but literally means “raw” as
in “unprocessed.” Most digital cameras are designed to rapidly convert the raw
picture data into finished JPEG or TIF files. Most also include a raw format
setting, which switches off in-camera processing and instead writes the image
data directly to the card, with minimal or no photo processing whatsoever.
The camera processor makes several adjustments to each image before it
gets stored on the media card (or in RAM), such as interpolating colors. RAW
photos store the unprocessed, un-interpolated data; but don’t include the
camera’s white balance settings or any other effects such as sharpening. Also,
Raw files are not down-sampled to 8 bits of color per pixel as JPEGs are, so they
preserve all the color information your camera’s sensor is capable of capturing.
The RAW format, when processed on the computer into a finished photo, is
invariably of better quality than an in-camera processed equivalent. And because
a RAW photo contains the full range of color and tone captured by the camera, it’s
often possible to correct white balance and exposure mistakes after the fact in
imaging software, making pictures look exactly as if they were properly exposed
on the best white balance setting in the first place.
However, saving a photo in the RAW format (versus letting the camera
convert it to JPEG) results in very large files, and these files must be processed
on a computer using the manufacturer’s photo capture software (usually supplied
with the camera). Additionally, many photo browsers and editors don’t recognize
these proprietary RAW files so you may not be able to view them in the browser
or work on them in an editing program. So, if you shoot RAW you should also
archive everything in a standard JPEG or TIF format so you'll be assured of
having the best chance of being able to open and use the files in the future.
[Note: Photoshop Camera Raw (built into Photoshop and Photoshop Elements)
supports many camera types and can import RAW files from all the major camera
makers. Also, the Microsoft RAW Image Thumbnailer and Viewer download
provides thumbnails, previews, printing, and metadata display for RAW photos
from most Canon and Nikon digital cameras on Windows XP.]
You may want to save your photos in RAW + JPEG, which saves RAW and
JPEG files at the same time. Use the JPEG for quick review or use, and turn to
the RAW file for serious editing.
Note
When shooting RAW, it’s sometimes advisable to shoot with some
overexposure. This gives more flexibility when you gamma-correct the photo
in your photo editor, where you can redistribute the tones to push them down
into the shadow parts of the photo to create good shadows. Since there are
no set rules for overexposure when shooting RAW, you should practice to see
how much overexposure is needed for a particular situation. And don’t forget
the auto bracketing option (discussed later).