The 1x-A teleconverter can be used with Olympus Zuiko 2/250mm, 4.5/300mm, 2.8/350mm and 6.3/400mm lenses.
This increases the focal length of the main lens by a factor of 1.4, while maintaining its intrinsic characteristics. The automatic diaphragm and meter coupling as well as the minimum focusing distance of the prime lens are retained.
The speed of the main lens is reduced by one stop.