actual aperture
1Aperture — For other uses, see Aperture (disambiguation). f stops demonstrated on a lens …
2Numerical aperture — The numerical aperture with respect to a point P depends on the half angle θ of the maximum cone of light that can enter or exit the lens. In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes… …
3F-number — In optics, the f number (sometimes called focal ratio, f ratio, or relative aperture [Smith, Warren Modern Lens Design 2005 McGraw Hill] ) of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; …
4History of the single-lens reflex camera — The history of the single lens reflex camera predates the invention of photography in 1826/27 by one and a half centuries with the use of a reflex mirror in a camera obscura first described in 1676. Such SLR devices were popular as drawing aids… …
5eye, human — ▪ anatomy Introduction specialized sense organ capable of receiving visual images, which are then carried to the brain. Anatomy of the visual apparatus Structures auxiliary to the eye The orbit The eye is protected from mechanical injury… …
6photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
7motion-picture technology — Introduction the means for the production and showing of motion pictures. It includes not only the motion picture camera and projector but also such technologies as those involved in recording sound, in editing both picture and sound, in… …
8Depth of field — The area within the depth of field appears sharp, while the areas in front of and beyond the depth of field appear blurry …
9optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
10Film speed — is the measure of a photographic film s sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to measure the sensitivity of digital… …
