micro 4/3 so it only uses the Center part of the lens!! no distortions
they are very good almost optically neutral .
Most of the Centurys are made for Sony Pro Video cameras so they are optimised for smaller sensors not full frame .
Schneider Magna Com is absolutly stunning , this a a vaiable focal length reducer used in Cinama Projection lenses
the glass is high end industial , practically optically neutral .