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

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    CZJ EDF 7x40 Roof Prism Binoculars

    Does the glass darken from gamma or neutrons? I don't understand why the tritium would be hazardous, unless they painted bare tritium and put the phosphor in the reticle lines. Usually both are encapsulated in a glass phial.
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    USA, Maryland, January, similar to downy/hairy woodpecker but entire top of head red

    Warmed up to 60 F yesterday, 40 today. Did not see her.
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    New APC 42 Stabilized

    Is the Kite PM an older version of the APC model? I see it on their site but no prices, as if out of production. I have Zeiss Conquest HD 8x32 and 10x42. The APC is the same price zone as a Conquest HD 10x32, which would be lighter than the 10x42 and probably just as good in normal light...
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    Copyright of optical system? Why no replicas of high grade binos?

    In the near future, it will be possible to train a robot to disassemble vintage binoculars. Perhaps they could remove the original glass and insert modern glass with better properties. But would that have any appeal? The fun in vintage is the workmanship that you can feel when using the tool...
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    8x42 vs. 10x42 Binoculars

    I have a Conquest HD 10x42 that I keep on a tripod aimed at the birdfeeder. When looking elsewhere, I'm always comparing various vintage binoculars to the Conquest 8x32. The Conquest is brighter in less than full light, but not necessarily sharper. The tripod mounting plate is a quick...
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    Checking Collimation

    What exactly does strabismus do that hinders... whatever sort of collimation tests were being talked about? Inability to focus on a pinpoint without eyestrain... makes you perceive two points even when the optics are perfect?
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    Checking Collimation

    My IPD is only 53mm, so I presume that I will not get accurate results from methods like defocusing a star, or moving back from the ocular when looking at a pinpoint, due to lack of Spacial Accomodation? Most full size binoculars only go down to an actual 55-54mm. I like wide field binoculars...
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    Checking Collimation

    Your book suggested using a Fresnel lens, which turned out not to work. It also says a lens made from inexpensive glass will work (since color correction is irrelevent), but I have been unable to find an 8" or larger example. You also mention that a telescope will work, but I presume that the...
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    USA, Maryland, January, similar to downy/hairy woodpecker but entire top of head red

    But this below freezing weather is all the way down the east coast. Not many insects this time of year. I saw predicted temps as low as in Fargo N.D. !!!
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    USA, Maryland, January, similar to downy/hairy woodpecker but entire top of head red

    It must be a yellow-bellied sapsucker female. I have NEVER seen one before, and am surprised to see it in the winter. The other day we got the super cold weather and 3" of snow and I have not seen her. If the sap freezes up, what else can she eat? Have not seen her at the birdfeeder or...
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    USA, Maryland, January, similar to downy/hairy woodpecker but entire top of head red

    We get hairy & downy woodpeckers at the suet. This guy is girdling my holly tree. It is two stories high & maybe 30" away from a second story window. At the height of the window he is making rounded rectangles 2cm x 2-4cm, not very deep, all around, for a vertical span of say 8" - its a thin...
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    Swift Tyrol 15x60

    Sounds like a common configuration to me. How were you trying to free the frozen parts - a pair of strap wrenches, after soaking in penetrating oil? It looks like there is a crack in the "threaded sleeve" which I refer to as the helical. If you can free them, you may be able to fix the crack...
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    Recommendations for good binoculars for smallish IPD

    I'd kill for an IPD that wide. I'm 53-54mm wide. I find that using wide angle classic porros helps me percieve a single image instead of two partial images. For current production, the Zeiss Conquest HD is stated as 54mm minimum IPD
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    Testing Binocular Stability

    This is interesting but I don't understand your transition from speaking of the time required to achieve maximum resolution, to speaking of spatial frequencies and arcminutes. I suppose that the brain will control the saccade rate and take more visual snapshots per second, as the vibration rate...
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    Light transmission comparison esp. Zeiss

    That thread does not have any links in it.
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    how old is this Swarovski Habicht DV 7x42?

    Thanks. So the 1955-ish is likely to be close to the 1958 & 1963 models, which is really not too much less than the 1980 in the right graph. From 70% to 80% ish, where the 1980 adds about 5% to 10%.
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    how old is this Swarovski Habicht DV 7x42?

    Thanks, there is so much information that I get bunny-trailed into other directions. So the SN is in the earlier part of the range from 1955 to 1962.
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    how old is this Swarovski Habicht DV 7x42?

    I can't find anything relating to the "traditional" Habicht, only to the SL variant which started in 1980.
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    how old is this Swarovski Habicht DV 7x42?

    John again, post 26 https://www.birdforum.net/threads/3-new-8x30-reviews-by-holger-merlitz.371675/page-2 By 1963, DV coating was capable of slightly over 80% transmission across most of the visible spectrum - though with the limitation of a strong yellow cast to the image The yellow cast would...
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    how old is this Swarovski Habicht DV 7x42?

    Thanks guys. Using your reference posts to try & figure out its light transmission, but its a real slog. Anyone know the answer? Post 18 by John: https://www.birdforum.net/threads/3-new-8x30-reviews-by-holger-merlitz.371675/ A) the primary coating used on Swarovski products from 1948 to 1982...
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    Swarovski SL porro models

    That page seems to have gone away. Anyone download a copy?
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    how old is this Swarovski Habicht DV 7x42?

    What does the DV stand for? see https://shopgoodwill.com/item/165288232
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    Focussing: Just Do It!

    I need a clearer understanding of how eyeglass prescriptions are written, and how that relates to focusing binoculars in the "nearer" and "further away" directions. When you turn the CF wheel such that the shaft extends, that moves the focus "nearer." Usually that is CCW. I find that the...
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    Premium (Alpha) vs Image stabilized

    Which brand & model of IS binoculars has the smallest acutal IPD? Usually they go some distance narrower than the listed spec. My eyes are 53mm, and most bins don't go below an actual 56mm. I gravitate towards wide angle bins because it gives me a better sense of having a full FOV; I'm probably...
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    Bushnell 10 x 42mm Sportsman Binoculars

    How have they held up over the last 17 years? I'm seeing them on ebay for around $50 and up.