"In <em>optics</em>, a deviation in the rays of light when unequally refracted by a lens or reflected by a mirror, so that they do not converge and meet in a point or focus, but separate, forming an indistinct image of the object, or an indistinct image with prismatically colored edges."-Wright, 1902

Aberration

"In optics, a deviation in the rays of light when unequally refracted by a lens or reflected…

An aluminum set of disks that correctly finds the time needed to develop photos in solution

Watkins's Factorial Calculator

An aluminum set of disks that correctly finds the time needed to develop photos in solution

"The photographer's camera corresponds to the camera-obscura. A darkened box, adjustable in length, takes the place of the darkened room, and an achromatic convex lens is substituted for the aperture in the shutter." &mdash; Avery, 1895

Bellows camera

"The photographer's camera corresponds to the camera-obscura. A darkened box, adjustable in length,…

Eastman's Kodak camera from Switzerland in 1907.

Kodak Camera, 1907

Eastman's Kodak camera from Switzerland in 1907.

A diagrammatic illustration of how a photograph is produced.

Photography

A diagrammatic illustration of how a photograph is produced.

An illustration of a woman in a long dress and hat standing behind a camera.

Woman Standing Behind Camera

An illustration of a woman in a long dress and hat standing behind a camera.