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

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  1. kimmik

    Two classics side by side

    Here are some crops of areas of interest. Henry you nailed the Optolyth, 30x60, with the smaller eyepiece. The prism is a porro with a rhomboid prism to center the image, as John has described. I did take apart a 30x80 optolyth for cleaning and they seem to have the same prisms. And...
  2. kimmik

    Two classics side by side

  3. kimmik

    Focus to infinity for short-sighted users

    was the diopter set to 0 on the noctivid? mine (and presumably all) noctivid easily makes 4D with the diopter at 0. with the diopter at 4, there is still a tiny bit over overdrive so 4.5/5D max total correction is about right.
  4. kimmik

    TIR, prism choice and its effect on image quality

    TIR in optical fibre lets light run many kilometers without a boost. That is in the order of billions of TIR reflections. Even then it is probably the glass attenuation that reduces signal, rather than imperfection in the TIR. Of course even superconductivity is not actually perfection...
  5. kimmik

    The Apple Digital Binocular, gen1

    Virtual visit has been the point of binoculars all along, isn't it? No need to stop at 1x virtual visit. The magnification can be set arbitrarily. Its just a question of how good the main cameras are. like the situation on phones.
  6. kimmik

    The Apple Digital Binocular, gen1

    Wonder how much zoom the forward facing main cameras can provide, then the headset will be effectively digital binoculars with 120degree AFOV 4k resolution. Three element freeform aspheric eyepieces. Just like camera phone, the first iphone didn't have much zoom capability nor image...
  7. kimmik

    High power binoculars, the less well known meaning

    Handbook of optics, Bass 2009, reference manual for the optical society of America: "The amount of flux which can be transmitted through a prism or other optical element depends on both its angular aperture and its cross-sectional area. The greater the amount of flux which can be transmitted...
  8. kimmik

    Optics misused Terminology.

    Totally lost me there I’m afraid 😂
  9. kimmik

    High power binoculars, the less well known meaning

    Thread '- The nominal luminous power of the binoculars:' https://www.birdforum.net/threads/the-nominal-luminous-power-of-the-binoculars.384516/
  10. kimmik

    High power binoculars, the less well known meaning

    What is a high power binocular? Most people define it as magnifying power. 15x is higher power than 10x. The other definition is light gathering power - 10x56 has greater power than 10x42, fairly straight forward. But also, 10x56 has greater power than 15x56, due to the greater true FOV.
  11. kimmik

    Optics misused Terminology.

    I'd like to add a parameter to the original list, that is not well known but is a deciding factor for me when choosing bino: Etendue per mass, also known as light throughput per mass. A binocular with high etendue per mass is the equivalent of a car with high power to weight ratio. Another...
  12. kimmik

    CA always seems to mean lateral, is longitudinal really not seen?

    Its funny the diagram got the rays wrong for lateral CA. Most people can’t tell though. The simulated image is correct.
  13. kimmik

    CA always seems to mean lateral, is longitudinal really not seen?

    Long-CA: ca arising from lateral part of exit pupil Shows most when your pupil is off center Lat-CA: ca arising from lateral part of image Shows most when your gaze is off center Long-CA: error of focal plane improved by stopping down the objective or the eye pupil Lat-CA: error of...
  14. kimmik

    Canon EOS 80D always slightly "fuzzy"

    Panning
  15. kimmik

    Canon EOS 80D always slightly "fuzzy"

    The first images show motion blur plus out of focus. Last image is out of focus. Assuming you can get good shots of static object: Lens optics are ok Try servo mode focus plus burst Up the ISO Stop down a bit Slightly faster shutter speed Check IS modes on lens, some are not good with panning...
  16. kimmik

    New Zeiss binos 8x40 SFL and 10x40 SFL

    Now that I look for the phenomenon, it is present to varying (minimal) degree in many binoculars, more so in the wider angle eyepieces. None are bothersome though, just something to be aware of down the list.
  17. kimmik

    why do the 8x50 and 10x50 Ultravid have the same FOV?

    Bigger prism - less vignette for a given TFOV Smaller prism - lighter, more compact The 8x50 could hypothetically be given a larger FOV eyepiece, but the edges will be heavily vignetted. It would also lose eye relief unless you want more weight. The purpose of the 8x50 is ease of view so the...
  18. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    I don't recall seeing a single star in my recent binoculars. They are for nature and travel, if that clarifies my use for you. If you wish to discount the opinion of astro users on birdforum, I am the least of your "concern".
  19. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    I don’t have much to add at this point. Using your example, 1000x mag with 1mm aperture is also useless. We just differ fundamentally in our priorities, and seems like most people are happy with mag being more important than aperture, leading to the existence of 30x50mm etc.
  20. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    Good post, I think I see the fundamental difference in our reasoning now. You propose magnification to be more important than aperture. I propose aperture to be more important than magnification.
  21. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    “It just is” “That is how it has always been” “Not ambiguous to me, so you are reading it wrong” “Why fix whats not broken”
  22. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    I provided detailed logic to support my perspective and readers can think for themselves.
  23. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    You won $1million. Except that isn't a dollar sign, it is S and I overlapped which just looks like a dollar sign by coincidence. If 10x50 isn’t meant to be mathematical, perhaps they should stop using this ambiguous label. My point is, it is rather convenient for the marketers, that 10x50mm...
  24. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    Agree, though that problem isn't solvable by 10x50 either. So 12x25mm=300, and 7x42mm=294, are comparable? What about 50x20mm=1000, same as 12x80mm=960? Marketers will be happy to know you support their claim that their dollar binos can compare with 12x80mm units.
  25. kimmik

    Binoculars convention should be Aperture Divide Magnification, not Magnification x Aperture... ?

    Better than 10x50 I agree. 50mm, 10x would be even better IMO. I would not pay the same price for 10x25 vs 10x80, so i prefer to think of them as 80/10 and 25/10. Marketers will happily advertise 1000x50 telescopes (as you've noted many times before), but perhaps they wont succeed with...
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