One of the new features of iOS 4.1 released last week was an HDR ability in the camera app.
HDR stands for high dynamic range, it’s a method of joining multiple images together to get the best overall result for a particular scene. Phone cameras and even dedicated digital cameras often have automatic exposure, so when the photo is taken the camera decides the exposure depending on the situation.
The camera will regularly do a poor job of this process particularly in situations where you have a high contrast in light between different parts of the shot. A subject standing with a scene behind them in full sun for example will often have dark shadows on their face as the camera sets the exposure for the background.
What HDR technics attempt to do is take multiple images all with different exposures and morph them together, so all areas of the shot have the best exposure to show them.
The new feature in iOS 4.1 in my first tests does a pretty good job. When you go into the camera app you will see a new option HDR at the top of the screen, this is where you can turn it on or off. By default you can get the camera to save both the regular image and the HDR image, this can be setup in the Photos settings.
There will be photography purists that may frown upon Apple’s simplification of HDR but if it gets a better photo for those of us who like to take pictures wherever we are it can’t be all bad.
To get an idea of what it does in the real world have a look at these examples. In each case the first image is the HDR image and the second is the plain image without the setting.