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
Diaphragm (birth control) increase in the length of the vagina, occurs during arousal. This means that during intercourse, the diaphragm will not fit snugly against the pubic bone because it is carried higher up the vaginal canal by the movement of the cervix. If the diaphragm is inserted after arousal has begun, extra care must be taken to ensure the device is covering the cervix. A woman might be fitted with a different size diaphragm depending on where she is in her menstrual cycle. It is common for a woman to wear a larger diaphragm during menstruation. It has been speculated that a