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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

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  1. H

    Star Test Result Question

    Well, the prisms are the same type (Schmidt for angled version, Porro for straight), but the roof in the Nikon is offset so it doesn't split the objective light cone. Because of that there's no need for phase correction and no problem if the roof edge isn't perfectly made, a defect that seems to...
  2. H

    Star Test Result Question

    Hi Chris, I think you may be back to using a few too many rings for a clear view. Just to remind myself that spotting scopes don't have to be this bad I star tested my wife's Nikon Monarch 82 ED again. What I saw was remarkably little difference between the appearance of the inside and outside...
  3. H

    Star Test Result Question

    I should have mentioned that in order for all those spikes and flares to be attributed to air turbulence they should be in motion, something like looking at a stream bottom through flowing water. The 30m distance would seem to be long enough, but maybe your pinhole is too large or maybe your...
  4. H

    Star Test Result Question

    Too much turbulence is the problem this time. Sometimes the air is just not steady enough for photographs. Were you able to see clearer outside focus rings visually?
  5. H

    Star Test Result Question

    Chris, Those are much too far out of focus, maybe 15-20 rings or more. You really can't even see most of them because they're all blended together. Here's an image of 3 rings inside focus that just happened to be on my desktop. It's from a binocular, stopped down from 42mm to 21mm. The...
  6. H

    Star Test Result Question

    How many rings are you using? Between 2 and 5 is the most useful. Very sharply defined rings on only one side of focus is not a good thing. As spherical aberration increases the rings gradually disappear on one side while they grow more sharply defined on the other side. What is wanted is...
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