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Zeiss Victory Diascope 85 t* fl star test pictures (1 Viewer)

BoldenEagle

Well-known member
Hi,

here are star test diffraction patterns for Diascope 85 fl inside and outside focus. Zoomed to 75x and light source was silver flagpole knob about 40 meters away.

I think there is not anything else wrong with it but some spherical aberration is involved.

In direct comparison with my Kowa Prominar 883, Diascope usually feels the sharper one. Haven't done any precise resolution comparison but this Diascope sample likely is better than my Kowa.

I have earlier posted star test pictures of my Prominar sample to the Kowa section. Obvious differences are Kowa's prism defect and maybe some amount more of spherical aberration and a little bit of coma and astigmatism.

Juhani
 

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binomania

Well-known member
Hi,

here are star test diffraction patterns for Diascope 85 fl inside and outside focus. Zoomed to 75x and light source was silver flagpole knob about 40 meters away.

I think there is not anything else wrong with it but some spherical aberration is involved.

In direct comparison with my Kowa Prominar 883, Diascope usually feels the sharper one. Haven't done any precise resolution comparison but this Diascope sample likely is better than my Kowa.

I have earlier posted star test pictures of my Prominar sample to the Kowa section. Obvious differences are Kowa's prism defect and maybe some amount more of spherical aberration and a little bit of coma and astigmatism.

Juhani

Hi, thanks for your experience!
I come from the astronomy sector and I love doing star tests :), however
the objectives of the spotting scopes are mounted under pressure in a cell protected by O-Rings or another sealing system. This allows excellent protection from infiltration, but can generate a "warping" of the elements and deviations on the optical axis due to the uneven compression of the sealant. For this reason I don't like doing this kind of test in sports optics...but i thank your for your report.
 

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