In this article, we look at the intelligent auto mode, providing a guide to what it is for, and how it works
Intelligent auto mode is the direct descendant of program auto-exposure mode, itself born from ordinary auto mode. With automatic exposure, the camera senses the light and saves you from the drudgery of manually setting the camera to make a correct exposure. The earliest auto-exposure cameras could only adjust the lens aperture, but with the advent of electronically controlled shutters in SLRs in the mid-1970s, automatically controlling the exposure via the shutter became a possibility.
In aperture priority (A) mode, the photographer sets the aperture manually with the camera choosing the shutter speed, while in shutter priority (S) mode, the photographer controls the shutter speed and the camera controls the aperture. Program (P) mode combines the two, giving control to the camera. This is how you get PASM (M for full manual control).
Then the intelligent auto mode came along. Not only does it allow the camera to control the shutter and aperture, but also the ISO sensitivity and other settings. To help the Intelligent auto mode decide the most appropriate settings, it evaluates the scene using scene-detection mode. At first, this was the preserve of compact or mirrorless cameras using live view, but more recently, DSLRs have been able to offer scene detection via the use of higher-resolution exposure-metering sensors.
If the top of the frame is relatively bright and the lower half is darker, the intelligent auto mode may decide this is a landscape photo and so try to preserve the highlights in the sky. If it detects a face occupying a relatively large area of the frame, it will expose for a portrait. In some cameras the intelligent auto mode will even detect movement in a scene and up the ISO to maximise the shutter speed in an attempt to freeze the subject more effectively. That’s iAuto for you.