Aperture adjustment ring
The aperture setting ring , or aperture ring for short, is used on photographic lenses to manually set the f-number .
The aperture ring is labeled with the aperture numbers. Most aperture rings lock into place at full steps, but there are also some with stops at half steps. In the case of automatic programs or iris , the aperture is set to the largest value (usually 16, 22 or 32), with some systems such as the Pentax KA it is locked in a special automatic setting. The camera then controls the appropriate aperture at the set shutter speed.
Many newer lenses for single- lens reflex cameras no longer have an aperture ring, with these the aperture is set on the camera housing using a rotary knob. The Japanese manufacturer Canon was a pioneer in this field in 1987 with its EF lenses (autofocus), other manufacturers such as Nikon kept the aperture ring for some time and gave the user the choice between aperture ring and rotary control. However, all lenses newly launched by Nikon in recent years do not have an aperture ring.
Diaphragm ring with locking of the smallest diaphragm for operation with automatic iris
Most lenses have the aperture ring at the back. The aperture is set to 11 on this lens. The orange 22 marks the smallest aperture (= largest f-number).
