TS Super Wide Angle 20mm
Very good sharpness within the complete apparent field of view.
x-axis: distance from optical axis in °, y-axis: resolution in arc minutes
Apparent Field of View:
The apparent field of view is approx. 62° - a little bit less than given by the manufacturer data.
Very good contrast.
Slight cushion distortion.
Not too easy. You will need some practice in finding the correct distance where the center as well as the edge provide a sharp image at the same time.
Good quality with foldable rubber eye cup.
A nice wide angle eyepiece. At F/5 you will see noticeable aberration close to the edge. Recommended for F/6 or slower.