Diaphragm (optics) bright spots, for example night cityscapes. Some cameras, such as the Olympus XA or lenses such as the MC Zenitar-ME1, however, use a two-bladed diaphragm with right-angle blades creating a square aperture. Similarly, out-of-focus points of light (circles of confusion) appear as polygons with the same number of sides as the aperture has blades. If the blurred light is circular, then it can be inferred that the aperture is either round or the image was shot "wide-open" (with the blades recessed into the sides of the lens, allowing the interior edge of the lens barrel to effectively become the iris).
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