Iris diaphragms from the standard programme G (fully closing)

Fully closing iris diaphragms consist of 2 semi-diaphragms staggered at an angle of 180° in two levels. A common turning ring is positioned between these two levels. The necessary distance between levels amounts, depending on the kind of diaphragm, from 1 to 3 mm. These diaphragms have a fastening thread on their outside for fixing.