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Recent content by LarryO
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Celestron Nature DX 8x42 green #71332, black #72322 really optically the same?
The original, non-ED Celestron Nature DX 8x42 binoculars have received very high ratings among inexpensive, "beginners'" models, usually at the top of the list in the under-$200 category, with performance rivaling that of much more expensive options, e.g. see: Finding the Best Binoculars for... -
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Old Ultravid vs new Trinovid
Examples? Documentation? Ditto It can be confusing to readers when a forum member considered to be expert and knowledgable represents "impressions" as established facts -- post #17: "ED glass" means "Extra low dispersion", a range of glass doped with lanthanides." I am unaware of any glasses... -
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Old Ultravid vs new Trinovid
Tenex (post #17) states that "ED glass" means "Extra low dispersion", a range of glass doped with lanthanides." This is incorrect. "ED" glasses are, indeed, "extra-low dispersion" ones, but they are not generally lanthanum-containing glasses. As Ignatius (post #10) notes, they are in a group... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
Agree on both points. Users willing to report differences in apparent DOF with different light spectra, ambient by time of day or deliberately created by filters, are invited to include the criteria used to defined the perceived DOF, allowing others to adopt them. In this way a set of... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
This seems a quite different case, with eye accommodation indeed eliminated. My understanding is that, if the telescopes are well corrected for longitudinal chromatic aberration, focus of the orange and blue rays should be at or near the same image plane. Theoretically, there should be small... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
"Apparent DOF" is definitely a subjective characteristic, dependent on visual accommodation, so subject to variation among observers. The conjecture is that, even for individual observers, it might vary among binocular models or time of day, owing to differences of accommodation dependent on... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
The recent contribution to this old thread reminded me of the exchange with tenex about my suggestion that the apparent DOF of different binoculars could arise from differences in eye accommodation based on differences in spectral transmission. (Tenex rejected in very strong terms even the... -
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Which of the older Trinovids are best ?
For reference in this discussion, listed below are sites with what appear to be quite thorough histories of Leitz/Leica binocular models, with dates of introduction. Data in them for earlier models is credited to Peter Abrahams, one of whose compilations I cited in posting #5 above... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
LarryO said: The eye, using a simple lens, suffers from longitudinal chromatic aberration, so its ability to accommodate for different distances in a view can depend on the distribution of colors in the light involved. ------------------ tenex said: "Suffers? There's good evidence now that the... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
LarryO said: There are actual transmission spectra for a Trinovid BN 10x42 and an Ultravid (non HD) 10x42 in post #4 of the thread 'Coatings Questions' <Coatings questions>... The spectra do display differences, and the post discusses ideas about which of those might affect perceived brightness... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
Jerry - It makes perfect sense. As mentioned in my post #23 here, and again in post #44, at least one coatings engineer also said that little could be deduced from reflected coating colors about actual spectral transmission and that the reflected colors could, to some extent, even be chosen to... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
Some comments: 1. There might not be large numbers of birdforum members who have possessed multiple examples of the same alpha-binocular model displaying different coating colors, let alone members who have had the examples in hand at the same time. That could account for there not having been... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
My apologies. I may have tried too hard to compress what the sentence was meant to convey about why several aspects of binocular performance might depend on the spectral transmission of different lens coatings. Following is an attempted breakdown: "The idea, maybe 'absurd'..." -- This was... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
The idea, maybe 'absurd,' was that apparent depth of field in a pair of binoculars, as opposed to that in a photograph, could vary with eye accommodation to visual distance and thus with the color spectrum involved. One bit of helpful input on the point might be comparisons of apparent... -
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Trinovid BAs still a 'sweet spot' among Leica binoculars?
Those reports of differences in focusing requirements, apparent depth of field, and view vividness for different coatings within a model run are observations I have not heard before. One possibility is that differences of transmission spectra accompanying different coatings could be involved...