Leica Summitar 50/2

Summitar 50mm f/2 is a classical Leica thread (or screw) mount lens, manufactured by Leitz from 1939 through 1953. It replaced an even earlier Summar 50mm f/2 model and in turn was eventually replaced by Summicron 50mm f/2. The lens did not have coating until after WWII (circa 1945-1946), although many of the uncoated lenses were sent back to Leitz for post-manufacture coating. The optical construction of the lens consists of 7 elements in 4 groups. The build quality of the lens is superb - all metal parts help the lens withstand decades and while most lenses would have some cosmetic blemishes, unless users really abuse the lens, it can probably last another 50 years. Summitar is a collapsible lens, meaning that the top half of the lens can be collapsed into the mount, reducing the overall size of the lens, but needs to be expanded before you can start shooting with it. The lens measures 50 x 42cm (1.9 x 1.6in) when fully expanded and only 42 x 42cm (1.6 x 1.6in) when collapsed. It weighs 205g (7.2oz). The lens accepts special, L type filters, which screw-in to the front side of the lens, although you can also use Leica SNHOO 39mm to L adapter, which would allow you to use standard 39mm screww-in filters with this lens. The minimum focusing distance is 1m (3.3ft) and the minimum aperture is f/16.