Limited camera control has often been a source of frustration for users and developers who want to flex their mobile photography muscles within iOS. The default camera app has a very limited set of controls available, with a simple HDR toggle and AE/AF lock among the only visible options.
With the advent of iOS 8, during the keynote at WWDC that this is about to change. Manual camera control will now available through the application programming interface (API), with developers able to access more functionality than ever before.
AnandTech has taken a closer look at some of the specifics within the camera API and has found that almost all exposure parameters will be accessible. ISO sensitivity, shutter speed, white balance, exposure compensation and focus will all be opened up, allowing for greater control and more flexibility for app makers.
For a detailed look at what all these exposure terms mean,.
Note that mobile devices generally all have fixed apertures, if you were wondering why there was no aperture control accessible in that list.
The documentation also mentions bracketing via exposure compensation, shutter speed and ISO. Bracketing is a useful technique that lets the photographer take a series of shots of the same scene in quick succession with a particular exposure value changing each time.
For example, in a tricky lighting situation, the photographer may want to bracket their shot on either side of the camera's metered exposure to get the most accurate results. Bracketing is also a technique that is used to make HDR images by capturing different exposures of the scene and then blending them together in post-processing.
Apple has also opened up a grey card functionality that can be used to manually override the automatic white balance reading. As outlined in the AVCaptureDevice API, the camera delivers specific red, green and blue values from the scene in order to calculate the neutral white point for determining white balance.
Many of these granular exposure controls are not new to the mobile photography world, with the Pro Camera app on some Windows Phone devices giving similar options.
Unfortunately the API makes no mention of accessing raw photos, a feature that is available on some Nokia handsets and is most likely.
Finally, while all these exposure controls will be opened up to developers within the API, the default iOS camera app will only gain exposure bias (EV) options for now.