Tamron Flat Field 2x Tele Converter Adaptall 2 Mount System MODEL O1F

This 2X converter, compatible with most Adaptall-2 mount lenses, provides very good optical performance. The 6 element, 5 group optical design is housed in a moderately long barrel which is about twice the length of conventional 4 element 2X converters. The flat field optical design minimizes off-axis aberrations; spherical and chromatic aberrations are also extraordinarily well controlled. Tamron's literature states that this converter is designed for lenses with a focal length of 90mm and longer. Nevertheless this converter performs well with all Tamron zoom lenses which have a stationary master group (the rearmost group of lens elements). This converter can also be used with many Tamron wide to tele zoom lenses for doubling macro magnification, and usually results in better off-axis macro performance.