To revisit, a high dynamic range photo combines multiple photos taken at different exposures to create a single photo that looks more like what your eyeballs are able to detect than a regular digital photograph. (Dynamic range is basically the range between the darkest and lightest parts of an image. (Check out Ansel Adam’s Zone System for more on this.)
In HDR mode, the iPhone 4 captures three exposures to combine into an HDR photo: an underexposed shot, a normal exposure and an overexposed picture. Even though it’s shooting that sequence of pictures pretty fast, it’s not instant. So if you move the phone, or if your subject’s moving around, you’re going to wind up with some mutant friends with three arms or whispy ghosts when the phone tries to mix all the photos together. As you can see in the picture above, taken while walking, we’ve got phantom cars, mutant trees and weird road markings.
Focus, Focus, Focus
Having your subject in focus is key to making it look right when the iPhone 4 combines everything into a single image – in part, so it’s easier for the software to do its job mixing all of the photos together without scrambling them into a fuzzy, weird mess.
Is it a HDR-worthy photo?
The key is to make sure you have a lot of dynamic range to capture in the first place. In other words, something with a decent range of contrast between light and dark. Photos that are relatively flat (like in low light) at best show no improvement, or at worst suffer when you slap HDR on ’em.
The great thing about the iPhone 4’s HDR feature is that it preserves the original photo along with the hopefully new and improved version, so it doesn’t cost you anything to experiment. If you hate the result, just delete it.
The iPhone 4’s camera was already awesome. While its new HDR feature doesn’t produce miracles, it does make our favourite phone camera even better, so it’s hard to complain too much.