The Canon AE-1 Program is a 35 mm single-lens reflex camera that uses Canons FD mount lenses. It was introduced in 1981 as the successor to the Canon AE-1, five years after that cameras introduction. The major difference was the addition of the Program AE mode first seen in the A-1. This mode sets both the shutter speed and aperture automatically, albeit with a slight bias towards the shutter speed setting. The user focuses the camera and then presses the shutter button. For those desiring more control, the AE-1s shutter priority auto-exposure and full manual modes are still available.