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APO,Superachromat,ED glass-HELP (1 Viewer)

casscade

Well-known member
What does it all mean. Zeiss says their bins have superachromats, Leica has an HD glass and an HD APO. Is any of this better than others when it comes to binoculars or is it all hype to help sales. I would like to know what it all means. Thanks.
 
There were some excellent discussions on HD, ED and FL style glass here in the binocular forum some time within the last year. Some of the regular members did an excellent job of explaining much of it. Maybe one of them remembers which thread it was under and can direct you to it. I seem to remember it being in one of the subforums but I could be mistaken.

Sorry I could not help more but this is definitely an excellent question to get clarification on.
 
Generally these are all marketing terms. "Apo" is generally shorthand for "apochromatic", which means much the same thing as "achromatic", although technically, the terms refer to different levels of the same feature (achromat, apochromat, superachromat, in that order).

These terms are used to indicate that the optics are well-corrected for chromatic aberration, which is the fact that different colors (or wavelengths) of light refract at different angles, and will without correction not focus to the same point through a given lens.

The terms "ED", "FL", "HD", etc., are also marketing terms generally relating to the specific proprietary type of optical glass used that has specific dispersion characteristics which that manufacturer has developed in order to provide as much chromatic aberration correction as possible.
 
Generally these are all marketing terms.

No. not really.
apochromatic and achromatic are defined technical terms in physics.

"superachromatic" is an informal term but at least informative.

"apochromatic", which means much the same thing as "achromatic",
Not quite the same thing.


technically, the terms refer to different levels of the same feature (achromat, apochromat, superachromat, in that order).
No.
The correct order is: achromatic, superachromatic, apochromatic.

achromatic: chromatic abberation corrected for 2 out of 3 of the primary colours.

superachromatic: somewhat better than achromatic but not fully apochromatic.

apochromatic: chromatic abberation corrected for all 3 of primary colours.


The terms "ED", "FL", "HD", etc., are also marketing terms generally relating to the specific proprietary type of optical glass used that has specific dispersion characteristics which that manufacturer has developed in order to provide as much chromatic aberration correction as possible.

ED: extra low dispersion. indicated a physical properties of certain types of glass.

FL: type of glass that is doted with flouride ions.

HD: high definition. A pure marketing term. Can mean about anything. Meaningless.

Hope this helps/clarifies.
T
 
HD: high definition. A pure marketing term. Can mean about anything. Meaningless.

Although HD doesn't tell the buyer anything specific about the glass type used in a binocular or scope, I don't think it's fair to label the term meaningless--that might suggest to the original poster or others new to the sports optics scene reading this thread that the "HD" label is a ruse in comparison to ED, FL, etc. In practice, the labels ED, FL, HD, LD, XD and others such labels are ways that manufacturers signal to buyers that they are using some kind of exotic glass or fluorite (and perhaps other aspects of design) to correct for chromatic aberration better than their products that are not labeled as such. I'm not aware of any examples among major manufacturers where these labels aren't indicative of easily measurable differences in performance (although we still haven't had anyone post a definitive description of the Leica HD Ultravids versus the non HD! I've been planning to post an inquiry to the forum about this. Haven't had a chance yet to try them out myself). For example, the much more expensive HD labeled Swarovski scopes are supposed to have better CA correction than their non HD Swarovski equivalents, and they do!

Another important point for anyone puzzling over how to use these terms--in contrast to the technical terms that have been described above (achromatics, apochromatic)--there is no way to rank HD, LD, ED, FL, XD etc according to which is superior based on the label alone--it just tells you that the product is superior to otherwise identical or similar products from the same manufacturer. Truth be told, even the APO label (implying apochromatic performance) and the term apochromatic tend to be used rather loosely in the sports optics world, so if you really care about which product best minimizes chromatic aberration among these choices, you'll have to read reviews or try them yourself. In practice, I find these terms indicative of similar performance, so choosing among them is usually swayed more by other aspects of their design and optical performance.

--AP
 
Although HD doesn't tell the buyer anything specific about the glass type used in a binocular or scope, ....
That's what I have been saying.


In practice, the labels ED, FL, HD, LD, XD and others such labels are ways that manufacturers signal to buyers that they are using some kind of exotic glass or fluorite (and perhaps other aspects of design) ...

This or that or something different. "Anything" in other words.


-that might suggest to the original poster or others new to the sports optics scene reading this thread that ...


...there is lots of hot air in manufacturers' brochures, salespeoples' mouths and BF postings.

Salespeople and other "would-bes" like to use jargon, and acronyms in particular to impress their opposites. Many are and keep their mouths shut, afraid to expose their "innocence". The opposite strategy is much better (Try it!): If someone bugs you with his gibberish: Ask him straight away to explain what it means!
It's both fun and revealing!


-there is no way to rank HD, LD, ED, FL, XD etc according to which is superior based on the label alone----AP
That's what I've been saying: mostly meaningless.

Thank you for confirming my statements.
T
 
Ha! Thanks for that reminder. No offense intended Robert, but I'm looking for something a bit more detailed with respect to the differences in CA control. I'm surprised that no one has done a more comprehensive test. From your description, I'd guess you aren't generally very aware of (i.e. bothered by) CA because I see quite a bit in the Leica 8x32 and 8x42 Ultravids, but maybe the 10x32 are better (I know the 8x20 are). I find the Zeiss 8x32 FL to be much much better (the difference immediately obvious to me) in this respect than Leica BN and Ultravid, Nikon LX and Swarovski EL.

--AP
 
That's what I've been saying: mostly meaningless.
...Thank you for confirming my statements.

You're correct that we agree on these points, but given the way they asked the question, I just wanted the original poster or others reading this thread to know that these labels _do_ indicate the use of special optical materials or other designs to significantly reduce chromatic aberration in comparison to similar models, and are in that sense not meaningless labels. Granted, the differences aren't as large as with scopes, but in my experience, the use of these materials in binoculars improves performance.

--AP
 
... From your description, I'd guess you aren't generally very aware of (i.e. bothered by) CA ...

--AP

This would certainly appear to be the case for me, Alexis, at least to a significant degree. Perhaps that bit of analysis is best left to someone with an acute, and irksome, awareness of CA.

Cheers,
Robert
 
You're correct that we agree on these points, but given the way they asked the question, I just wanted the original poster or others reading this thread to know that these labels _do_ indicate the use of special optical materials or other designs to significantly reduce chromatic aberration in comparison to similar models, and are in that sense not meaningless labels. Granted, the differences aren't as large as with scopes, but in my experience, the use of these materials in binoculars improves performance.
--AP

Hello Alexis!
Thank you for your reply.
My remarks were not meant to offend anyone but to point out (to newcomers as well as some "addicts") that terms are not all equal. Some have a defined meaning and can be found in a dictionry of physics (such as achromatic / apochromatic), others are undefined and accordingly used liberally. HD .... there is HD TV and all sorts of other high definition devices. In an optical instrument it could also mean that the manufacturer has recently switched from aluminium to magnesium alloys, for example, or from a low-gear focussing mechanism to one with a high gear ratio. Without further explanation it is not a revealing term.

As regards chromatic abberation, there is some indication in the physically meaningful terms. Flouride-doted glass is also an indicator as we have come to learn that it provides a remedy for a good deal of CA.

I think in the end, when it comes to choosing from a narrow range of (probably be expensive) instruments testing with one's own eyes becomes an essence. People, as you have pointed out, have highly varying degrees of awareness or "bothering factors" with respect to this or any other deficiency of their instrument.

In the very end everything is quite literally in the eye of the beholder, isn't it?

Chromatically conscious,
Tom
 
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