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
Diaphragm (birth control) the diaphragm. "Contraceptive Technology" reports that the method failure rate of the diaphragm with spermicide is 6% per year. The actual pregnancy rates among diaphragm users vary depending on the population being studied, with yearly rates of 10% to 39% being reported. Unlike some other cervical barriers, the effectiveness of the diaphragm is the same for women who have given birth as for those who have not. The diaphragm does not interfere with a woman's natural cycle, therefore, no reversal or wait time is necessary, if contraception is no longer wanted or needed. The diaphragm only has to be used