These great quality lenses are convertible from f/16 to the f/4.5-f/5.6 of our L10514. There is a diaphragm at the back to make it f/16 instead of f/4.5 to f/5.6. However, the diaphragm can be taken out to convert it to the L10514 (metal diaphragm pops out with a bit of force). They have been taken out of a medium format portrait camera and are in great condition. High quality Computar zoom lens, 105mm to 150mm. All elements are AR Coated optics with front element multi-coated. Includes threaded front lens shade and cover. Front clear lens diameter is 50mm and rear clear lens diameter is 30mm. Barrel is 70mm diameter, Front lens shade is 85mm diameter. It is Rare to find a medium format zoom lens and when you find one they are usually very expensive. At 150mm the lens appears to cover more than a 4" x 5" format. In addition to use as a camera lens, they make a great objective for a compact zoom telescope. They also make a nice zoom enlarger lens, telephoto camera attachment, finder scope, etc. We believe they can be used as an adjustable laser beam expander but one of our customers tried it for that purpose and advises that it didn't make a very good beam expander for lasers. We have a decent quantity so if you want to incorporate these into a product, we can give you a quantity discount. If you take it apart, you will find lots of optics and mechanical parts to wet your creative juices.