Why shoot raw?

The answer to the above question is simply, control over the interpretation of the image. When you shoot JPEG, the camera’s on-board software carries out all the tasks listed earlier to produce a color image, then compresses it using JPEG compression. Some cameras let you set parameters for this conversion—typically, a choice of sRGB or Adobe® RGB as color space, a sharpness value, and perhaps a tone curve or contrast setting—but unless your shooting schedule is atypically leisurely, you probably can’t adjust these parameters on an image-by-image basis, so you’re locked into the camera’s interpretation of the scene. JPEGs offer fairly limited editing headroom—large moves to tone and color tend to exaggerate the 8-by-8-pixel blocks that form the foundation of JPEG compression—and while JPEG does a pretty good job of preserving luminance data, it really clobbers the color, leading to problems with skin tones and gentle gradations. When you shoot raw, however, you get to control the scene interpretation through all the aforementioned aspects of the conversion. With raw, the only on-camera settings that have an effect on the captured pixels are the ISO speed, shutter speed, and aperture. Everything else is under your control when you convert the raw file. You can reinterpret the white balance, the colorimetric rendering, the tonal response, and the detail rendition (sharpening and noise reduction) with a great deal of freedom, and you can even reinterpret the basic exposure itself, resetting the white and black points.

Requirements

To complete this article, you will need the following software:

Adobe Photoshop CS2

• Try (win)
• Try (mac)
• Buy

Prerequisite knowledge:

Basic understanding of your digital camera, digital imaging, and Photoshop CS2

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