Diaphragm (optics) the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system. Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris. See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm. A natural optical system that has a diaphragm and an aperture is the human eye. The iris is the diaphragm, and the opening in the iris of the eye (the pupil) is the aperture. An analogous dev in a
A Poke in the Eye (With a Sharp Stick) A Poke in the Eye (With a Sharp Stick) A Poke in the Eye (With a Sharp Stick) is the title of the first show in what later became the iconic "Secret Policeman's Ball" series of benefit shows for human rights organization Amnesty International, although it pre-dated by three years the first show to bear that name.. The film of the show was titled "Pleasure At Her Majesty's" which is sometimes mistakenly thought to be the title of the actual benefit show. The landmark 1976 show starring the Monty Python, Beyond The Fringe and The Goodies teams and other top