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).
Thoracic diaphragm abdomen. The dome curves upwards. The superior surface of the dome forms the floor of the thoracic cavity, and the inferior surface the roof of the abdominal cavity. As a dome, the diaphragm has peripheral attachments to structures that make up the abdominal and chest walls. The muscle fibres from these attachments converge in a "central tendon", which forms the crest of the dome. Its peripheral part consists of muscular fibers that take origin from the circumference of the inferior thoracic aperture and converge to be inserted into a central tendon. The muscle fibres of the diaphragm emerge from many