The ε-Extender is a high performance extender,
composed of 7 elements in 5 groups. Coma
aberration is corrected by a special Takahashi design. Even
when the focal length is enlarged 1.5 times, under optimum
imaging conditions a star image equal to or better than the
direct focus star image can be obtained. Across all models,
optical performance is 2 microns or less (RMS-SPOT) in the center
and up to 8 microns at the edge of a full frame sensor.
