Camera

A camera holds an optical image still long enough to record it. The objective and image plane are common; the material or device placed at that plane changes the rest of the chain.

Lens systemOBJECT / SCENELENS SYSTEMAPERTUREIMAGE PLANE
Material receiver

Film camera

Exposure is accumulated directly in a photosensitive material.

FRAME GATE
Scanned charge

Analog electronic camera

An optical target is read as a continuously varying electrical signal.

TARGETSCANBEAM
Sampled charge

Digital camera

A pixel array samples the image before electronic and numerical processing.

ADC / DATA