iPhone, iPod touch camera by photographing a subject for metering, the shooting information, and then calculate the exposure.
iPhone, iPod touch to use the camera and metering.
By operating the picker surface exposure plan, according to the photometric data ISO, aperture, shutter speed is displayed.
Note: iPhone 3G does not use. Because, 3G is the aperture and shutter speed can be obtained from the information in the camera.