Aperture indicator for enlarging lens - uses internal electrical circuit with spring and individual studs to make circuit to lamp indicator

摘要

The aperture setting indicator is primarily for an enlarging lens. A contact plate (2) with individual contact studs (3) is located in the lens barrel (1). There is a rotating contact spring (4) which moves with the iris diaphragm setting ring (6). This spring makes electrical contact with the contact studs (3) on the plate and completes a circuit to a lamp indicator showing the aperture selected. A separate lamp is used for each aperture.