Diaphragm (optics) photographic lens is called an iris diaphragm. In the early years of photography, a lens could be fitted with one of a set of interchangeable diaphragms , often as brass strips known as Waterhouse stops or Waterhouse diaphragms. The iris diaphragm in most modern still and video cameras is adjusted by movable blades, simulating the iris of the eye. The diaphragm has two to twenty blades (with most lenses today featuring between five and ten blades), depending on price and quality of the device in which it is used. Straight blades result in polygon shape of the diaphragm opening, while
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