Diaphragm (optics)

In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through 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.

Iris diaphragms versus other types

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 photographic lens is called an iris diaphragm.

Iris (1987 film)

Iris is a 1987 Netherlands film directed by Mady Saks and starring Monique van de Ven.

Plot

A young woman, Iris, runs away to the big city on her eighteenth birthday. She moves in with an architect and decides to become a veterinarian. With an inheritance she buys an existing clinic in a backwoods town where Iris is leered at by the men, scorned by the women. Cruel jokes and gossip eventually lead to violence.A local thug breaks in her house while she is out. When she returns home late night, he attacks her, drag her to the wooden stairs, ties her hands, stretch her legs wide apart and ties to the railing of stairs and rapes her brutally.

References

External links

Iris (EP)

Iris is Miranda Sex Garden's second release, and first EP.

Track listing

Kelso

Kelso is a town in the Scottish Borders, and for which many places are named.

Places

Kelso (horse)

Kelso (April 4, 1957 – October 16, 1983) was an American thoroughbred race horse considered among the best racehorses in history. In the list of the top 100 U.S. thoroughbred champions of the 20th Century by The Blood-Horse magazine, Kelso ranks 4th, behind only Man o' War (1st), Secretariat (2nd) and Citation (3rd). In his long career, Kelso defeated many leading Thorougbred racehorses including Carry Back, Gun Bow, Bald Eagle, Tompion, Never Bend, Beau Purple, Quadrangle, Roman Brother, Crimson Satan, Jaipur, Ridan and Pia Star, as well as other top thoroughbreds, often conceding weight under handicap conditions. In doing so, Kelso beat more champions and Hall of Fame horses than any other thoroughbred racehorse in the 20th Century.

Background

Kelso's pedigree was undistinguished. Born at Claiborne Farm near Paris, Kentucky, he was sired by a well-known racehorse who was an unproven stallion, Your Host. Kelso's dam was the unheralded Maid of Flight (although her sire was Count Fleet and her grandsire was Man o' War). Kelso was her first foal; he was scrawny, runty and hard to handle. He was a maternal grandson of U.S. Triple Crown champion Count Fleet, who is ranked #5 by The Blood-Horse. Before he set foot on a track, owner Allaire du Pont had him gelded in the hopes of calming him down. According to many, it did not work; Kelso was never a well-mannered horse. He was named for Mrs. du Pont's friend Kelso Everett and, like Mr. Everett, who went by the nickname of "Kelly", so did the horse.