History

Digital Single-Lens Reflex (DSLR) cameras have been around for about 20 years or so, one of the first commercially available ones was Kodak DCS-100, which was based off of the earlier non-commercial DSLR Nikon F3 camera system (Aasland). They work by focusing light rays through a lens onto a mirror that then reflects them onto a CCD sensor, or sensors, inside the camera body. The duration and amount of light let through is controlled by the shutter and aperture of the camera. These light rays are then absorbed by the CCD and then turned into a digital image that is then formatted for display on various devices.

Kodak DCS 100Canon T3i

Kodak's first DSLR (ca 1991)                                                                                My modern Canon Rebel T3i DSLR
Image Credit: http://www.nikonweb.com/dcs100/                                        Image Credit: Self