The Sony Ultra Wide Converter helps widen your perspective even further of the wide-angle lenses like SEL20F28 and SEL16F28 Alpha E-Mount lenses from Sony. It ensures an increased focal length of 24 mm and 18 mm, a magnification ratio of 0.086x and 0.059x, and a viewing angle of 88? and 103? for the SEL20F28 and SEL16F28 lens respectively. This converter is constructed from 3 elements in 3 groups for reducing unwanted aberrations. For added protection from external damage, this converter comes with front and rear lens caps, along with a carrying case.