Automatic lens
From The Glossary of Digital Photography
A lens that has an automatic diaphragm. The opposite of an automatic lens is a manual lens, which requires the diaphragm to be stopped down from viewing wide open to the proper size for exposure. In the case of a manual lens, there usually is a ring on the lens to twist to close the diaphragm before making the exposure. Manual lenses are usually less expensive and are found most frequently in inexpensive telephoto lenses and in specialty lenses. See also automatic diaphragm
