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
Electromagnetic diaphragm of capacitive sensor, and shares properties with condenser microphones. The difference between the electromagnetic diaphragm and a condenser microphone is that a condenser microphone operates on the basis of air transmission, has a very thin membrane instead of a diaphragm, and cannot be placed against a body to sense sounds within the body. The electromagnetic diaphragm for stethoscopes was patented by Clive Smith in 2002 and is used on Thinklabs electronic stethoscopes. Electromagnetic diaphragm An electromagnetic diaphragm is a form of capacitive sensor used on an electronic stethoscope. The diaphragm is coated with a conductive material. A conductive plate is