As digital SLRs gain in popularity, making sense of sensor formats becomes increasingly important. Right now, there are two main contenders, full frame and APS-size. “Full frame” refers to a sensor close to the same size as an actual 35mm film frame: 36mm x 24mm (3:2 aspect ratio). APS refers to the “Classic” frame size of the defunct APS film size, or 25.1mm x 16.7mm (still 3:2.)
For the camera buff who really wants to know the details of what makes a digital camera work.