The Camera

Parallax- Displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

Pentaprism- A pentaprism is a five-sided reflecting prism used to deviate a beam of light by a constant 90°, even if the entry beam is not at 90° to the prism.

Pellicle mirror- A pellicle mirror (diminutive of "pellis" - skin or film) is an ultra-thin, ultra-lightweight semi-transparent mirror employed in the light path of an optical instrument, splitting the light beam into two separate beams, both of reduced light intensity.

Optical- of or pertaining to sight or vision; visual.

Aperture: A space through which light passes in an optical or photographic instrument, esp. the variable opening by which light enters a camera.

Shutter: Each of a pair of hinged panels fixed inside or outside a window that can be closed for security or privacy or to keep out light.

Exposure: An act or instance of being uncovered or unprotected.

Depth of field: The distance between the nearest and the furthest objects that give an image judged to be in focus in a camera.

F-stop: a camera setting corresponding to a particular f-number.

Focal length: the distance between the center of a lens or curved mirror and its focus.