Along with several much-appreciated bug fixes, version 4.1 of Apple’s iOS for iPhone, released this week, brought with it a few new features. I’ve been playing with one of them: built-in high dynamic range (HDR) photography.
HDR is, Wikipedia tells us, "a set of techniques that allow a greater …range of luminance between the lightest and darkest areas of an image than standard …photographic methods. This …allows HDR images to more accurately represent the wide range of intensity levels found in real scenes." In photography, the effect is accomplished by taking multiple exposures of the same scene, then merging them algorithmically. I’ve done some HDR experimentation previously using my Canon S90, which does the necessary exposure bracketing, but actually getting an HDR photograph required, at minimum, uploading the pictures to the computer, firing up the image editing software, and running an HDR process to merge them. Depending on the software you were using, it could be more complicated still.
With iOS 4.1, the procedures is somewhat simpler: turn HDR on, and take a picture. All of the processing is done in-device.
By default, iOS saves both a standard and HDR image of each picture you take, which makes it very easy to do A/B comparisons. Here, for example, are both versions of a picture I took outside the mall last night. Notice the greater definition to the lights in the picture on the right. There is also variation in shading visible in the lamp shade at the top left of the HDR image that is blown out in the standard shot.
Here’s another example, taken at the same location in a different direction. As before, there’s less bloom around light sources like the Barnes & Noble sign, and much more detail visible through the store windows in the HDR shot.
Keep in mind that these are all handheld shots with a camera phone—at night, an area of particular weakness for the iPhone historically. Particularly arriving as it does within a free iOS upgrade, I have to say the new HDR feature is pretty fantastic.