Hermann
Well-known member
The 3% difference vs Zeiss HT might be due to the AK-prisms.
That's what I think as well.
Hermann
The 3% difference vs Zeiss HT might be due to the AK-prisms.
LOL :-O that's interesting! :t:This is brilliant! For what it's worth, ma'am, in my personal accounting system "several" is definitely a number greater than four - I would say at least 7 or 8 but less than 10-12. :t:
The 3% difference vs Zeiss HT might be due to the AK-prisms. Haven't seen any ham in the SF yet...
Thanks Vespo,CJ: You can find it in the 2018 hunting catalog, attached a screen shot of it.
The 2017-18 Nature catalog still have the 42mm HT in it so not mentioned there.
The 3% difference vs Zeiss HT might be due to the AK-prisms. Haven't seen any ham in the SF yet...
https://www.zeiss.com/content/dam/S...e/catalogs/produktkatalog-hunting-2018-en.pdf
Actually, I don't think that's the case as the extra length of the A-K prisms would make for a faster focal ratio which would increase aberrations (CA, etc) if the physical length of the binocular stayed the same. It would also muck up the Centre of Mass and reduce the effect of the touted ergonomics. Sorry!Y'know... the SF design would seem to offer plenty of space for Abbe-Koenig prisms... hint hint Herr Schmitz ...
Strange that the SF has HT glass but no better transmission than the FL's, with no HT glass.
Lee,CJ
Vespo's screen shot is more or less identical to the page in the 2018-19 Nature Catalogue which has not yet been put onto the Download Centre of either the Zeiss UK or Zeiss Germany websites. I am sure the HT glass is in the prisms as this is the most obvious place to put it but Zeiss personnel at Bird Fair would not confirm which components are involved.
BTW CJ could you explain what you mean by green ham? You see green, fair enough, I don't, but where does the ham come into it?
Lee
Actually, I don't think that's the case as the extra length of the A-K prisms would make for a faster focal ratio which would increase aberrations (CA, etc) if the physical length of the binocular stayed the same. It would also muck up the Centre of Mass and reduce the effect of the touted ergonomics.
As far as I can tell you've just effectively agreed with everything I said. As well as the slightly longer optical path through the A-K prisms, note they are also physically much longer which would require stronger refractive lenses throughout the optical train or again suffer greater aberrations if the physical length of the bin remained the same - which it would have to, what with it already being a very long bin. All in all A-K's are not an option for the SF.Agree on the balance issue, but as the glass path of an A-K prism is 5,2 times the aperture as against 4,62 for S-P (quoting Holger Merlitz here), the former could get away with a slightly longer focal length in the same housing, and consequently a "slower" focal ratio.
The glass path in the prisms is an integral part of the design. Without the prisms the objectives of the best corrected binoculars would exhibit significant spherical and chromatic aberration.
John
Lee,
I just checked the Australian Zeiss website too, and it is no help in clarifying matters - there is no mention of any HT glass, and they mention "multiple" fluoride lenses (meaning more than 1 but we really don't know how many).
As far as the "green ham" goes - it's more 'ham' than 'green' - it's a kind of very slight greyish greenish ham colour. I don't know if that's a common saying in the world but a kind of slight 'old ham' colour is a pretty good approximation. It's just on the warm side of the ledger.
Chosun :gh:
LOL ! :-OCJ
I have never heard anyone liken any colour of anything to ham in any way.
Over here ham means cured pork of a particular cut and the salt makes it a deep red colour which kind of sounds weird when mixed with green as you descibe it. When cooked our ham/salt-cured pork goes grey but if cooked quickly can have brown almost-burned marks on it. I suppose if ham went bad and invaded with bacteria it might go green or maybe green with mould but surely this doesn't happen often enough to become a by-word for a particular shade of whatever it is you are trying to describe. Boiled ham is a kind of gentle pink colour but would need some serious contamination of some kind to go green.
All of this is very appetising but doesn't bear any resemblence to the view through any optical view I have ever seen.
Can you tell I am struggling to understand any aspect of your green-ham comparison?
Lee
Thanks Vespo,
That's interesting. If that is correct (and I'm still not discounting a mix-up) , it could be as little as 1 HT lens in the eyepiece ....
The colour cast I see in the SF is very subtle, yet it is there (I should fess up that I probably have supernatural white balance detection powers due to previous work requiring high level scrutiny, and so it wouldn't surprise me if others don't see it to the same degree or even at all). I would say that the T* coatings of the SF are likely of a different Flava to the HT's too.
Chosun :gh:
As far as I can tell you've just effectively agreed with everything I said. As well as the slightly longer optical path through the A-K prisms, note they are also physically much longer which would require stronger refractive lenses throughout the optical train or again suffer greater aberrations if the physical length of the bin remained the same - which it would have to, what with it already being a very long bin. All in all A-K's are not an option for the SF.
Chosun :gh:
Not necessarily - sure you probably get the best HT bang for the buck in the prisms, but the HT glass range covers the full gamut - flints, crowns, various grades suitable for prisms - there's 12 different products last time I looked at the Schott catalogue. They could go anywhere or nearly everywhere (I'm not sure if there is what would be a HT grade of fluorite these days or if it is classified that way - pesky definitions, terminology, and language againAny HT glass would be in the prisms.
The SF might have been optimized for daylight (and birding) in the first place, but now it's also replacing the HT in the Hunting catalog...
HT glass might have been added later, as it mostly would increase transmission in the blue spectrum and not the 92% figure.
But it's only a speculation...
Did you try the HT and SF side by side in natural light outdoors?
The grey version?
Maybe you should try a later sample...
As far as I can tell you've just effectively agreed with everything I said. As well as the slightly longer optical path through the A-K prisms, note they are also physically much longer which would require stronger refractive lenses throughout the optical train or again suffer greater aberrations if the physical length of the bin remained the same - which it would have to, what with it already being a very long bin. All in all A-K's are not an option for the SF.
Chosun :gh:
That's what I see - very very slight light pinkish grey with a hint of greenish. Some others see it too. It fits perfectly with what I see of the transmission chart.
Chosun :gh:
I have ample evidence at home of how colour perception can differ as Troubadoris and me often disagree as to whether a fabric or a paint etc is blue or green......