Coverage (lens)

In a camera system the coverage must be large enough to cover the sensor or film used.

In a view camera system, because the film plane can be moved independently of the lens plane, the lens must have enough coverage to cover the film while it is offset from the center of the coverage area.

[1]  A “full-frame” type lens produces an image circle that is large enough to cover a 35mm sensor.

An APS-C type lens often does not have the coverage to cast light on the entirety of a 35mm sensor, causing dark corners in the images.

[2] One common misconception about lenses is that focal length determines the angle of view for a lens, when in reality it is a combination of focal length, lens coverage, and sensor size.