Swarovski ATM or ATS HD? (3 Viewers)

[henry link]

Like John, I'd like to see an explanation for the 4% different attributed to the 25-50x eyepiece alone. The 20-60x zoom is certainly a complex eyepiece with 8 elements in 5 groups plus a flat waterproofing element for a total of 12 glass to air surfaces, but surely the 25-50x is about equally complex. I wouldn't be surprised to see the very same number of surfaces in its design, but in any case I doubt that such a sophisticated zoom could be done with fewer than 4 groups (certainly not less than 3) plus the waterproofing element which would subtract only 2 or at most 4 surfaces.

Swarovski was already claiming 0.2% reflection loss per surface for the old scopes using the 20-60x zoom. If we accept that claim there would be only a 2.4% loss from surface reflections in the 20-60x eyepiece. Add another 0.5% or so for about 25mm of glass thickness and the total loss appears to be no more than 3%. Are we supposed to believe that the 25-50x eyepiece has 101% transmission?

 

[Gijs van Ginkel]

John,
We have measured for the ATM80HD telescope with 25-50x zoom eyepiece light transmissions of 82% (that was shortly after the introduction of the ATM80HD) and that was similar to the data of Swarovski at that time.
The new ATS80HD telescope is reported in the recent Swarovski flyer to have a light transmission of 86% and that is an improvement if I compare it with our data, so I assume that Swarovski did improve the performance of the telescope. That occurs more often with Swarovski. I did a study for the Binocular History Society meeting of 2011 about the History and Quality development of Swarovski Optik from 1936-2011 and what I found was that in many items the performance was improved and often without publishing it, so this could very well be the case here, but I will ask the company.
Best regards,
Gijs

 

[Gijs van Ginkel]

Henry and John,
I forgot to mention that not only the difference in optical components can determine the light transmission of the optical system (which you udoubtedly know, but the type of optical glass also matters. In one of the publications of Schott glass, in which among others the high transmission optical glass was announced, which now probably is used in the Zeiss HT binoculars, some optical other glass types were also described and they had higher light absorptions than the high transmission glass and some of them considerably higher. So it may well be possible that Swarovski has used one or more components with some higher light absorption in the 20-60x eyepiece, what also could explain the differences in light transmission between the two different eyepieces.

 

[John Russell]

Gijs,

The transmission gains to be made by using HT glass in the thin elements of an eyepiece would be negligible.

The front prism of an Abbe-König system does not require the high refractive index of Bak4 for total internal reflection and we speculated on another thread that Zeiss might have used N-BK7HT here, where the in-glass light path is fairly long, to achieve improvements in the new Victories.

John

 

[henry link]

I agree John. The lenses in the 20-60x are small and thin. I was being quite generous assigning a total of 25mm to the glass thickness. Besides, whatever very high index types might be used in the 20-60x eyepiece would have high absorption mainly confined to the deep blue and violet, not very relevant to an overall light transmittance figure.

 

[Gijs van Ginkel]

So Henry and John,
What is your explanation then for the difference in light transmissions of the different systems published by Swarovski? Up to now, Swarovski always has supplied me/us with correct information when I asked for it (and we could and have checked that information as well). The only conclusion from your critisism, as I read it, is that Swarovski is lying to the outside world. Seeems very unlikely to me, since that would in the end damage their reputation. So we better ask Swarovski I think instead of speculating about it.

 

[John Russell]

As I pointed out, their marketing people have limited understanding of what the technicians are doing and are not capable of converting a metric FOV to imperial units.

Over and out.

 

[Gijs van Ginkel]

John,
No, it is not over and out. You make a statement about the professional quality of the marketing people of Swarovski and you do not give information what brings you to that statement. I visited a number of optical companies in Germany, Austria and Japan and it struck me, that all were very much aware of the importance of the professional quality of their employees including their marketing people. I also learned that Swarovski has done that to a high degree through a very professional quality management organisation which includes their marketing people. What I have seen makes it unthinkable that their marketing people give information that is not in accordance with the data from their technical staff and that includes the data in their flyers. Think about it what will happen if they supply us with controllable information and we would discover that it is not correct. The company then would loose all credibility and it would be very damaging to the company. On the basis of my information I do not agree with your statement.

 

[goldenwingedwar]

John,
No, it is not over and out. You make a statement about the professional quality of the marketing people of Swarovski and you do not give information what brings you to that statement. I visited a number of optical companies in Germany, Austria and Japan and it struck me, that all were very much aware of the importance of the professional quality of their employees including their marketing people. I also learned that Swarovski has done that to a high degree through a very professional quality management organisation which includes their marketing people. What I have seen makes it unthinkable that their marketing people give information that is not in accordance with the data from their technical staff and that includes the data in their flyers. Think about it what will happen if they supply us with controllable information and we would discover that it is not correct. The company then would loose all credibility and it would be very damaging to the company. On the basis of my information I do not agree with your statement.

Very well said, Swarovski are a creditable company, there will always be rather sad people trying to run down company for whatever their, maybe personal reason is.
In the UK Swarovkski also offer an excellent back up service for any lost caps, eyepiece covers. Although only a small point it is another example of the excellence of the company.
Over and out

 

[henry link]

Gijs,

I don't believe John has any personal reason to "run down" Swarovski. I know I don't. Count me as curious rather than accusatory. I'll be delighted if you can coax Swarovski into provided more information.

While you're at it I'd like to know what the single number they publish for light transmission means. Should we assume it's a "daylight" weighted figure or is it something else?

And I'd like to see an explanation for the difference in light transmission between Swarovski scopes and binoculars of approximately equal complexity. For instance, there is an 8% difference in the light transmission spec between the ATS scopes with the 20-60x zoom and the SV binoculars. By my count the cutaway views show only 2 or perhaps 4 more glass to air surfaces in the scopes and not much extra glass thickness, perhaps 20-30mm.

Henry

 

[John Russell]

I have absolutely no axe to grind with Swarovski. As I mentioned earlier, I own three of their products and am seriously contemplating the purchaseof a fourth. Their service too is exemplary.

What I nave noticed at Photokina and at bird fairs is that sales personnel, not only from Swarovski but also from other companies do not have a very good technical foundation. And that is the judgement of a layman.

If in their sales literature a FOV of 20 m @ 1000 m is expressed as 66 ft @ 1000 yds instead of 60 ft (20 yds) @ 1000 yds I think the doubts I expressed about their transmission figures are justified.

John

 

[Gijs van Ginkel]

Henry and John,
I have asked Swarovski for information and I have to wait for their answer.
Some infomation from the Schott paper from May 2011 with regard to new glass types may be relevant in the matter we discussed. The author, Schott employee Dr. Jedamzik, published a table in his paper which shows that a layer of 10 mm glass may vary in transmittance from 0,998 to 0,843 depending on the refractive index of the optical glass. So, the type of glass and its thickness is of importance for the overall light transmission of a telescope or a binocular. I can imagine that Swarovski does not want to share information with us about the type of optical glass they have chosen in their instruments, so we can at the moment only speculate about the cause of the light transmission difference between telescopes and binoculars (a difference which is found in the products of all producers and not only in the Swarovski instruments).
In the meantime we have measured light transmissions of the 8x32 SV and the ATX 95 and 85 and we found the following values:
8x32 SV: 90% at 500 nm, 92,4% at 550 nm. Swarovski reports 90% on their web-SITE
ATX 85 : 86,2% at 500 nm and 86,9% at 550 nm, Swarovski reports 86%
ATX 95: 86,2% at 500 nm and 87,6% at 550 nm. Swarovski reports 86%
From these data we may perhaps conclude that Swarovski takes an average transmission over the visible part of the spectrum ranging from roughly 500-650 nm, but I do not know.

 

[John Russell]

The author, Schott employee Dr. Jedamzik, published a table in his paper which shows that a layer of 10 mm glass may vary in transmittance from 0,998 to 0,843 depending on the refractive index of the optical glass.

Surely you mean wavelength, and in the ultraviolet it will be zero.
See: http://www.schott.com/advanced_opti..._glass_collection_datasheets_june_2012_en.pdf

John

 

[Gijs van Ginkel]

John,
Yes, you are right, I forgot to mention that the values published by Dr. Jedamzik were determined at 400 nm.
Gijs

 

[Gijs van Ginkel]

John and Henry,
I looked in my old files and I found the following transmission data for the (old) ATS80HD and the ATM80HD:
ATS80HDwith 20-60x zoom eyepiece: 500 nm=77%, 550nm=79%
ATM80HD with 25-50x zoom eyepiece: 500 nm=81%,550 nm=82%


Swarovski announces now for the new ATS80HD a light transmission of 86% I have no reason not to believe them.
Thinking a little more about the large difference in light transmissions of observation telescopes and binoculars: I think that could be explained in the larger optical pathlength in the telescopes with higher light absortion in the optical glass as a result. It seems difficult to attribute transmission differences of 10% and more to the difference in the number of glass-to-air surfaces (and we find these differences in instruments of all companies investigated).

 

[henry link]

Gijs,

That would seem to be a reasonable explanation, except that the total glass thickness in the cut views does not appear to be much more in the scopes than the binoculars. The 82mm objective glass thickness is probably about twice that of a 42mm binocular, but that would only add about 15mm. The Schmidt prism in the scopes is not very large since it's close to the eyepiece. I doubt that it has a longer light path in glass than the Schmidt-Pechen prism in the binoculars and the 20-60x zoom eyepiece doesn't look like it has much, if any, extra glass thickness compared to the SV eyepiece. Even if there is 25mm of extra glass thickness in the scopes and all of it is high index that still wouldn't have much effect on the light transmission at 550nm. It's another thing to puzzle over.

Henry

 

[BMAC2]

John,
We have measured for the ATM80HD telescope with 25-50x zoom eyepiece light transmissions of 82% (that was shortly after the introduction of the ATM80HD) and that was similar to the data of Swarovski at that time.
The new ATS80HD telescope is reported in the recent Swarovski flyer to have a light transmission of 86% and that is an improvement if I compare it with our data, so I assume that Swarovski did improve the performance of the telescope. That occurs more often with Swarovski. I did a study for the Binocular History Society meeting of 2011 about the History and Quality development of Swarovski Optik from 1936-2011 and what I found was that in many items the performance was improved and often without publishing it, so this could very well be the case here, but I will ask the company.
Best regards,
Gijs

Hi,
After reading the optics forums for a long time I am making a post to ask a question. I have the choice of purchasing an ATM 65HD or the new ATS 65HD both with the 25-50X eyepiece. From what I have read in this thread the new ATS 85HD has higher light transmission than the ATM model. Does anyone know if this is also true for the ATS 65HD vs. the ATM 65HD? Thanks.

TF

 

[Brian2]

I'm not too technical but I have an ATS80 hd and my brother and birding partner has the ATM80 hd. The ATM is slightly clearer than my ATS but the difference is very slight.

not sure why....I just notice his being a little sharper than my scope when we're out.

not sure that's of any use to you guys but I thought it was worth sharing.

and it should also be said that i'm delighted with my ATS model

 

[jan van daalen]

Brian,
Is your ATS model the latest one or the one before the ATM?
Jan

 

[BMAC2]

Brian,
Is your ATS model the latest one or the one before the ATM?
Jan

It would be the new ATS. The store has both the ATM and the new ATS in stock.

TF