I've been aware for years that the most difficult group shot to expose correctly is one that has a mix of races and complexions. If I exposed the Caucasian correctly, the African American would be underexposed. If I exposed for the the African American, the Caucasian would be overexposed. If I have lighting equipment and a controlled situation, at least I can take advantage of the inverse square law and place the Caucasian further away from the flash. But in less controlled settings, all I can do is try to average the exposure and get the faces under control with localized tonal adjustments in post-capture processing.
I wrote to head shot maven Peter Hurley for advice about this. I had just finished watching his newly released four hour video on his approach to taking head shots (which I give five stars and highly recommend, by the way) and realized, upon reflection, that there were no dark skinned subjects in it. I asked, "Are there any technical differences between shooting Caucasians and African Americans? Do you have any advice about what to watch for or plan for when setting up the lights and exposure for very dark complexions?"
Peter kindly responded with these words.
It's funny, years ago my first subject was one of my best friends and he's from Liberia. I began shooting him, he's really dark, and became known as the best for dark skin in NYC. I don't know why, but I loved the business, so it was nice that people noticed a difference. Now with everything digital I just take a shot and adjust my exposure accordingly. I'm more concerned with the color tones that the exposure really when I first start shooting, I can always adjust all that stuff later. It's a 1/2 stop more open than when I'm shooting a caucasian I believe. I don't set anything up any differently, but when adjusting white balance I find I'm fine tuning a bunch there. Hope that helps!So, Peter's advice is make adjustments on the fly. Use the histogram and look at the LCD or the monitor (if shooting tethered) and correct accordingly. Generally, there will be 1/2 stop difference between the two races. But color tones can be the real challenge. Use the white balance slider for this in post-capture processing.