Test
Results
Art.–Nr. TS-Zoom-7-21
TS Zoom eyepiece 7 to 21mm
Sharpness at 21mm:
Fine over the complete field of view.
x-axis: distance from optical
axis in °, y-axis: resolution in arc minutes
Sharpness at 7mm:
Not perfect, but acceptable. Of course a field curvature makes it
necessary to focus the center or the edge area.
x-axis: distance from optical
axis in °, y-axis: resolution in arc minutes
Apparent Field of View:
The apparent field of view is approx. 26° at 21mm and up to 39° at 7mm.
That is much less than expected. At least annoying if you rely on the
manufacturer data.
Contrast:
At 21mm: very good. Down to 7mm contrast gets noticeably worse.
Aberration:
Distortion is low (slightly cushion distortion) over the whole zoom
range. At low focal length chromatic errors in the edge area occur.
Eye Relief:
Comfortable.
Mechanical Quality:
Nice quality with foldable rubber eye cup and grip coated body. The zoom
mechanics is very good, perfectly balanced between tight and loose. There are
no “click-ins” for defined focal lengths.
Summary:
Mechanically recommendable, but with optical drawbacks.