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
The Flower of Gloster The Flower of Gloster The Flower of Gloster is a 1911 book by E. Temple Thurston (23 September 1879 – 19 March 1933), an Anglo-Irish poet, playwright and author. Published by Williams and Norgate, it sold well enough to merit a second edition two years later. A third unillustrated edition was published by Chapman and Hall in 1918, after which the book remained out of print for over half a century until being republished by David & Charles in 1968. A year before that, ITV had broadcast a 13-part children's serial of the same name (loosely) based on Thurston's original