What is the best exposure technique for Raw-format photos?

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September 1, 2011 at 1:43 pm  •  Posted in Q&A by  •  1 Comment

Until recently, I was shooting JPEGs with my Nikon D5100 but I have switched to Raw after reading an article about this format’s benefits. But what is the best technique for getting ideal exposures when shooting Raw photos? There seem to be a lot of different opinions on photography forums; which one do you recommend?
—Jack W.

I’m sure that one of the techniques that you have read about is called “Expose to the right”, Jack. Based on my experience with Raw capture when testing dozens of DSLRs, this is definitely the best bet for serious photographers. It’s based on a principle that was first explained by Michael Reichmann (in 2003) in a tutorial titled Expose Right and in an update (Aug. 2011) titled Optimizing Exposure. Here’s a brief summary: “… get your histogram as close to the right side as possible but not so close as to cause the over exposure indicator to flash. The ideal exposure ensures that you have maximum number of levels describing your image without losing important detail in the highlights.”

In other words, overexpose your Raw photos but without blowing out light-toned areas. Do note that this concept relates only to Raw capture and not to JPEG capture. It’s intended to optimize image quality by minimizing the appearance of digital noise, a grainy or mottled colour effect. Here’s a specific method that you might try when first experimenting with the Expose to the right (ETTR) principle: Be sure to activate your camera’s highlight warning (“blinkies”) feature in the menu. When viewing a RAW photo in Playback mode, you’ll also need to activate the screen that provides a histogram.

  • Start by metering a mid-tone, or a grey card, in the same light as your primary subject. This is only a preliminary step and will not often provide the ideal exposure for a Raw photo.
  • Increase exposure—with + compensation when using Aperture Priority mode, for example—to make a photo that appears too bright overall on the camera’s LCD monitor.
  • When examining the photo in the camera’s Playback mode, consider the histogram and any blinking that warns of a loss of detail in highlight areas; don’t worry about specular highlights such as ultra bright reflections on water.
  • If important highlight areas are blinking, set a slightly lower level of plus compensation and re-shoot. Check the new photo and the histogram. If important highlight areas are still blinking, set a slightly lower level of exposure compensation and re-shoot.

Especially in high-contrast lighting, you may need to re-shoot the photo several times—at different exposure levels—to get a Raw file that provides an ideal ETTR histogram. Later, using a versatile Raw-converter program, modify the photo for a pleasing—not overexposed—effect. Also experiment by setting a lower than default level for Noise Reduction in the software for the best possible resolution. All of this may seem a bit complicated and time-consuming at first. Based on my experience, however, the extra effort will pay off, with Raw-format photos with the best possible quality that any DSLR can provide.

One Comment

  1. Tom / September 1, 2011 at 4:07 pm / Reply

    This being such an important technique repeated many times at various seminars I have attended, why have the camera manufacturers not caught on. You would think they would include a feature to “expose to the right” for professionals and serious amateurs who use RAW regularly.
    In tricky lighting I often have to make multiple exposures trying to “guess” the best setting for maximum detail capture.
    An algorithm that adjusts the exposure so that a selectable percentage of pixels are over exposed would be a great benefit. We don’t always get the chance to retake an image as the “magic moment” has passed and our shot is less than it could have been.

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