There are many reasons to capture images as RAW files rather than JPEG files. However, it’s important to note that RAW image files require additional work to achieve the color balance you’re looking for, whereas JPEG files are color-balanced by the camera for you. JPEG files are also smaller than RAW image files, requiring less storagespace.
The advantages to shooting RAW files are:
# Increased bit depth allows for more color-correction “head room.” The JPEG format is limited to 8 bits per color channel. RAW images store 16 bits per channel, with 12 to 14 bits per channel of color information. Although it may sound confusing, this means you can do significantly more color correction without degrading the image or introducing color noise.
# After the RAW file is decoded, you work with the most accurate and basic data about an image.
# You control the white balance, color interpolation, and gamma correction aspects of the image during post-production rather than when shooting.
# The image file isn’t compressed, as JPEG files are, which means that no image data is lost.
# Most cameras are capable of and do shoot color outside the gamut range of JPEG (both Adobe RGB 1998 and sRGB), which means color clipping occurs when you shoot JPEG files. RAW files preserve the camera’s original image gamut, allowing Aperture to make image adjustments that take advantage of the full range of captured colors.
# RAW files give you control of noise reduction (luminance and color separation) and sharpening after capture. JPEG noise reduction and sharpening are permanently applied to the image according to the settings on the camera.