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

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  1. kimmik

    Globe effect/rolling ball, there is more to it

    Canon 15x50 - two thoughts. the high mag and aperture blurs out the foreground background so much that it alleviates the additional KI variable. Second thought is does it use a focusing element, or does it move the objective lens? Seems in my binos, the ones that use external focus (either...
  2. kimmik

    Globe effect/rolling ball, there is more to it

    Apologies I think I misunderstood the question. What binocular are you describing?
  3. kimmik

    Globe effect/rolling ball, there is more to it

    On my very crude simulation (and simplified without eyepiece or objective), there is interaction between the focuser and the field flattener, which results in changing distortion profile (observe the angle between rays, center vs edge). It would be very cool to see a proper simulation and...
  4. kimmik

    Globe effect/rolling ball, there is more to it

    Correct, thank you for following my logic. The K value distortion commonly discussed, is the special case K(in-plane). K(foreground) and K(background) can be different. I suspect this effect is due to putting strong glass curvatures near the internal focal point, which then applies...
  5. kimmik

    Globe effect/rolling ball, there is more to it

    I’m thinking it could be called: kappa instability. As a function of the in-plane kappa value, 0 KI means foreground and background have the same k value as in plane. The unit might be say, kappa per diopter.
  6. kimmik

    Globe effect/rolling ball, there is more to it

    Here is a puzzle for you. Why doesn’t camera viewfinder (dslr, mirrorless, superzoom etc) show globe effect? The distortion is pure rectilinear, which supposedly should cause extreme globe effect. When zoomed in, the magnification can be similar to binocular. The AFOV is pretty good too. So...
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