Swarobright Coating and P-coating (1 Viewer)

[John A Roberts]

Swarobright

Swarobright is Swarovski's brand name for dielectric prism coating.

It's a multiple layer coating that's used on the non-total internal reflection surface found on most roof prisms
i.e. it acts as a mirror.

So it's needed on both Schmidt-Pechan and Uppendahl prisms, but not on Abbe-Koenig ones
(for information on various roof prisms that have been used in binoculars, see post #32 and on at: New Horizons II ).

Dielectric coating was introduced in roof prism binoculars by Zeiss in 1998, and was then quickly adopted by other manufacturers.
It gives more vibrant colours and minimises the tendency to a yellowish image that was common to previous coatings.

Previous coatings used in terms of decreasing reflective efficiency were silver, aluminium and stainless steel *
All were deficient in terms of the blue portion of the colour spectrum, and so resulted in a slight yellow tint to the reflected image.

* See attached below an image from Nikon, showing the reflectance of various mirror coatings, from: Nikon | Sport Optics | Coating on roof (Dach) prism)


In relation to optical coatings, a dielectric coating is distinct from a metallic one. It uses interference to change the reflectance of a coated surface.
For an explanation and diagrams see: Dielectric Coatings

On binocular prisms, a large number of coating layers are used, to achieve the cumulative effect of reflecting the entire visible spectrum.
A Swarovski image from 2008 indicates that 30 layers were then used on the SLC 7x42.

However, since then the number of layers used has increased significantly e.g. Zeiss currently uses over 70 layers,
as indicated in the screen grab from: About Binoculars: Complex Design - ZEISS Hunting




Swarobright was progressively introduced across the various Swarovski roof prism product lines starting in late 1998.

In relation to binoculars:
• it was first used on two of the SLC models in late 1998;
• but not on the Pocket models and EL models until late 2001.

The staggered introductions on the SLC series, imply that the coatings needed to be tuned for each particular model.

n.b. Swarobright was not on the original EL x42 series from its introduction in mid-1999, as is indicated below,
and also in a 2010 thread: Lense coatings on old EL 8.5x42?


In relation to telescopes in 1998:
• the AT/ ST Porro prism series didn’t need the coating, and; the ATS/ STS Schmidt-Pechan prism series introduced in 2002 has Swarobright.

• the CT series of draw tube telescopes didn't have Swarobright coating, but; the CTC 75 introduced in 2001 and the CTS 85 in 2003 both have Swarobright.
(The earlier AZF series of draw tube telescopes from 1967 to 1993 used Abbe-Koening prisms, and so didn't need a mirror coating.)

 

[John A Roberts]

Details of Swarobright Introduction on Swarovski Binoculars

Swarovski’s optical devices are not marked to indicate the presence of Swarobright.
However, when introduced on various product lines, the box labels were for a time marked indicating the addition of Swarobright.

The following list is what I've observed from box labels, indicating:
(not observed on) first observed on, at the latest date by.

And for Swarovski numbering during the period:
• the first two numerals are the year of manufacture, add 1930, and;
• the next two numerals are the week of the year, from 01 to 52.


On SLC Models
8x56 (D6826 12329) D6847 22646, late 1998

10x50 (D6829 13770) D6851 24452, late 1998

7x42 (D7027 61277) D7033 62504, mid+ 2000

10x42 (D7039 65033) D7103 70724, early 2001

15x56 (D7138 82393) D7148 00624, late 2001 *

8x50 (D7101 70093) D7210 03016, early 2002

8x30 (D7204 84805) D7305 88434, early 2003 **


* In late 2001, the cumulative numbering used on all the SLC models - except the x30 ones - was reset.
The x30 models continued to use the original numbering series.

** On the 8x30, Swarovski describes the Swarobright version as the Mk IV, see post #11 at: Slc 8x30

In relation to the 7x50
Production/ demand seems to have been very low during the period, so I don’t have any images of box labels
to be able to indicate when Swarobright was added.

In relation to the 7x30
The 7x30 was discontinued in 2001 and never had Swarobright coating. For more detail, see post #12 in the above link.


On Pocket Models
10x25 (E7112 77339) E7142 81957, late 2001

8x20 (E7121 78943) E7217 86375, early 2002


On EL Models
10x42 (L7140 36497) L7145 38586, late 2001

8.5x42 (L7116 27961) L7207 43659, early 2002


Although Swarovski doesn’t talk in any detail about their Swarobright coatings, as indicted in the previous post,
the use of dielectric coatings has been substantially refined over the last 25 years.


John

 

[james holdsworth]

Are dielectric and phase correction coatings the same thing? I thought not…

 

[John A Roberts]

Phase Coating

Phase coating was also developed by Zeiss and first used in binoculars in 1988. And similarly, it was also quickly adopted by other manufacturers.

It was a significant advance for roof prisms, as it eliminated the slight softening of the image,
due to the de-phasing of the light column, from it being reflected off the two roof surfaces.

When the light column reaches the two intersecting roof surfaces:
• it is split in two;
• with each half being reflected first off one surface and then the other, and;
• then the two halves of the light column are recombined.
The less then perfect recombination results in the slight softening of the final image.

Although not the best of paired images (the roofed prism on the left doesn't show the double reflection of the light column),
it does demonstrate the effect of the double reflection on the orientation of the image verses a single non-roofed surface:




John


p.s. I’ve attached a copy of the original paper (in German) by the Zeiss employees Weyrauch and Dorband.

 

[Richard D]

Hi John, I can't say when SwaroBright was added to the 7x50s but I suspect it was added around the same time as the 8x50s, it's on my 7x50s D774063582

 

[John A Roberts]

Introduction of P-coating on Swarovski Products

Phase coating is referred to by Swarovski as as P-coating.
At the time of it’s introduction in 1989, Swarovski only manufactured two roof prism product lines.


One was the original SLC binocular models in 8x30 and 7x30, that had been introduced in 1885 and 1986.
In 1989 Swarovski made a number of changes to them, including adding phase coating, and they are known as the Mk II version.

They’re visually distinguishable from the earlier version, by the front of the objectives being enclosed.
See the details and images in post #5 at: Slc 8x30


The only roof prism telescopes in production at the time, were the AZF draw tube models in 30x75 and 25-40x75.
In 1989 the numbering of the units was changed, and presumedly indicates the addition of phase coating:

• Prior to 1989, a 6 digit numerical sequence was used for both models (with #70,046 being the latest that I’ve observed), and;

• From 1989 a seperate alpha-numerical number sequence was used for each (the earliest 30x75 being #59X 41027,
and the earliest 25-40x75 being #59Y 41031).


John

 

[GrampaTom]

Introduction of P-coating on Swarovski Products

Phase coating is referred to by Swarovski as as P-coating.
At the time of it’s introduction in 1989, Swarovski only manufactured two roof prism product lines.


One was the original SLC binocular models in 8x30 and 7x30, that had been introduced in 1885 and 1986.
In 1989 Swarovski made a number of changes to them, including adding phase coating, and they are known as the Mk II version.

They’re visually distinguishable from the earlier version, by the front of the objectives being enclosed.
See the details and images in post #5 at: Slc 8x30


The only roof prism telescopes in production at the time, were the AZF draw tube models in 30x75 and 25-40x75.
In 1989 the numbering of the units was changed, and presumedly indicates the addition of phase coating:

• Prior to 1989, a 6 digit numerical sequence was used for both models (with #70,046 being the latest that I’ve observed), and;

• From 1989 a seperate alpha-numerical number sequence was used for each (the earliest 30x75 being #59X 41027,
and the earliest 25-40x75 being #59Y 41031).


John

John and on say Zeiss 1040B it was labeled P * is that correct... same thing? So T*, which came first, followed by P* couple years later?

Woops, apologies for Zeiss question on Sawaovski.

 

[tenex]

The staggered introductions on the SLC series, imply that the coatings needed to be tuned for each particular model.

I don't see how "tuning" would be required? And the order of introduction doesn't seem to consistently reflect market popularity or special twilight use or any other principle. So I wonder whether it simply had to do with the manufacturing process, using up existing prism stocks etc. But it doesn't even happen at the same time with models of the same objective (and presumably prism) size, so it is really very odd. Surely dielectric mirrors, while a nice improvement, just weren't as crucial a priority as phase coating a decade earlier. And Swarovski wasn't introducing a whole new line of bins with this feature, like Zeiss FL or Leica UV, just performing incremental improvements.

 

[John A Roberts]

Hi tennex,

Adding to what I saw as the most likely (?) explanation . . .

The first EL's were produced in mid 1999, but then it took nearly 2 1/2 years - and over 30,000 units - before adding Swarobright,
with many of the SLC’s seemingly given higher priority (the EL numbering started at 05000).

The radical new style EL, was intended to be the flagship to establish Swarovski as one of the big three binocular brands.
So if it was easy to do so, why would Swarovski not have applied the all new technology as a priority, as an added selling point . . . ?


John

 

[John A Roberts]

Hi Tom (post #7),

In Zeissland:
T = Transparenz (the increased transparency associated with an anti-reflective coating), single layer lens coating.

T* = Multi layer lens coating.

P = Phase coating on a prism.

P* = Later phase coating designation.
(Perhaps to address questions along the lines of 'So how come the T coating is good enough to have a star, but the P coating isn't ?')

At the time, Zeiss were not as concerned to promote dielectric coating in the same way that Swarovski made a feature of it
(the difference between an established premier brand vs an emerging one?).


John

 

[tenex]

At the time, Zeiss were not as concerned to promote dielectric coating in the same way that Swarovski made a feature of it

... perhaps the new FL line had so many other features (AK prisms, "thin lenses") to promote that dielectric coating got less mention?

Adding to what I saw as the most likely (?) explanation . . .

OK, got it. You didn't mean "tuning" for each model, but getting Swarobright ready for prime time (ELs) using SLCs as a test platform. That does seem quite possible. Is there any evidence of different versions of it in SLCs over those 3 years?

 

[Hermann]

John and on say Zeiss 1040B it was labeled P * is that correct... same thing? So T*, which came first, followed by P* couple years later?

The Zeiss Dialyt 10x40B has a long, long history. The first ones had a simple coating (10x40B), followed by a multi-coated version (10x40BT*, ~1980). The next step was the introduction of the phase-coating in 1988/1989: 10x40BT*P. In fact, the first few made didn't even have the designation "P" on the binocular (or the box), Zeiss simply put a sticker on the box.

Hermann

 

[Hermann]

... perhaps the new FL line had so many other features (AK prisms, "thin lenses") to promote that dielectric coating got less mention?

The FL and its predecessor, the Victory 10x40BGAT*P, had AK prisms. And they don't require any dielectric coatings.

Hermann

 

[tenex]

I should have said, dielectric coating in the 32mm FLs got less mention.

 

[Alexis Powell]

...n.b. Swarobright was not on the original EL x42 series from its introduction in mid-1999, as is indicated below,
and also in a 2010 thread: Lense coatings on old EL 8.5x42?...

Interesting that you reference that old thread. I was the last one to post in it, and, my claim at the time was that all EL binoculars had Swarobright. I must say that I have a hard time believing that is not the case. If they didn't have Swarobright, they must have had something that was darn close, compared to anything else available from Swarovski at the time. Maybe some sort of precursor that wasn't marketed as "Swarobright" but that was essentially the same. In 1999, the EL were, in my experience, the first (and thus only) Swarovski bins that had a fresh bright contrasty view that was not yellow-tinged. Shortly thereafter, the SLC bins were updated with great fanfare about "Swarobright" to (among other things) remove the yellow tinge. To my eyes, the change in the SLC was a huge improvement. I handled quite a few EL from 1999 onward. I don't recall any significant change in the view through them until the focus speed was changed. Fast-focus EL have more chromatic aberration. I don't recall, nor do I know anyone who thought that the view through the EL changed with introduction of Swarobright. Our assumption at the time was that it was a marketing term that simply hadn't been applied before it was invented for the SLC, but that EL had always had it, even if not labeled as such. Consequently, there was never interest, amongst any birders who I knew, in replacing one's original EL to get the latest coatings. Even today, I get out my old EL from 1999 and it looks great (i.e. is in the same league) compared to my Zeiss 7x42 BGATP (which doesn't need reflective prism coatings) and my ~2015 production EL Swarovision with its Swarobright. By contrast, all of my bins with silver or aluminium coatings from that era are noticeably dimmer. Also, when Zeiss switched the Victory Compact series from silver to dielectric, it was a big improvement and well worth pursuing the upgrade.

OK, so I know I don't have any evidence, just my own experiences and recollections, but I am just having a very hard time believing that Swarovski made a significant switch to the prism coatings of the EL between 1999 and 2002. Are you sure? And if so, why did it make such a tiny (such that it was unnoticed by myself or anyone I know) difference in performance (by contrast to other binoculars, where we saw the switch to dielectric or the adoption of it in new models as a dramatic improvement)?

--AP

 

[GrampaTom]

The Zeiss Dialyt 10x40B has a long, long history. The first ones had a simple coating (10x40B), followed by a multi-coated version (10x40BT*, ~1980). The next step was the introduction of the phase-coating in 1988/1989: 10x40BT*P. In fact, the first few made didn't even have the designation "P" on the binocular (or the box), Zeiss simply put a sticker on the box.

Hermann

Like this? 1985ish... Sorry for messing with this thread...

 

[NDhunter]

Alexis:
A very nice summation of your experience. It seems John has provided his own time-line of the Swarobright coatings.
The quote to that old post from on here, does not offer anything much. If Swarobright was introduced in 1998, I am also thinking that all the EL's have it from the very start in 1999. Swarovski recognized the advantages, and the flagship would certainly have it.
I also had an early EL 8.5x42, and 2 more examples before I got the Swarovision version.
I am thinking if someone did some digging, the original EL promotion would include the Swarobright name, if they had
already been using the term.
Jerry

 

[tenex]

OK, so I know I don't have any evidence, just my own experiences and recollections, but I am just having a very hard time believing that Swarovski made a significant switch to the prism coatings of the EL between 1999 and 2002. Are you sure? And if so, why did it make such a tiny (such that it was unnoticed by myself or anyone I know) difference in performance (by contrast to other binoculars, where we saw the switch to dielectric or the adoption of it in new models as a dramatic improvement)?

This is a good question. I have little experience with Swaros of that vintage, but did once try an SLC that seemed yellow-tinged to me, and an early (wish I recalled the exact year) EL that did not. I liked its view very much, though not the open-bridge construction.

Can it really have taken 3 years to roll out Swarovision? Can we be sure that each model only had Swarobright once their box labels explicitly said they did, or is this just a labeling issue rather than product development?

 

[GrampaTom]

..........In 1999, the EL were, in my experience, the first (and thus only) Swarovski bins that had a fresh bright contrasty view that was not yellow-tinged. Shortly thereafter, the SLC bins were updated with great fanfare about "Swarobright" to (among other things) remove the yellow tinge. To my eyes, the change in the SLC was a huge improvement. I handled quite a few EL from 1999 onward. I don't recall any significant change in the view through them until the focus speed was changed. Fast-focus EL have more chromatic aberration. I don't recall, nor do I know anyone who thought that the view through the EL changed with introduction of Swarobright. Our assumption at the time was that it was a marketing term that simply hadn't been applied before it was invented for the SLC, but that EL had always had it, even if not labeled as such.........

OK, so I know I don't have any evidence, just my own experiences and recollections, but I am just having a very hard time believing that Swarovski made a significant switch to the prism coatings of the EL between 1999 and 2002. Are you sure? And if so, why did it make such a tiny (such that it was unnoticed by myself or anyone I know) difference in performance (by contrast to other binoculars, where we saw the switch to dielectric or the adoption of it in new models as a dramatic improvement)?

--AP

Unannounced running changes are common in manufacturing businesses. Marketing literature will not cover it all. The search for lower cost or better quality is constant and ongoing. Sometimes a new process is discovered by R&D or Process Engineering, maybe mid model year AND independent of the marketing departments scheduled plans. The process has to be proven to work in a production environment, (as distinct from say the lab). The only way to do that is to put it into production. If production viability, cost, or performance benefits are not assured proving the change works first, before announcement is a prudent choice. Once proven, marketing steps in. We cant know unless someone shows up who was there, but Alexis' surmise makes sense.. Swarobright could've been put into 1999 ELs as part of a running change, once proven then maybe it was put into the SLC and got marketed there first.

 

[henry link]

In relation to telescopes in 1998:
• the AT/ ST Porro prism series didn’t need the coating, and; the ATS/ STS Schmidt-Pechan prism series introduced in 2002 has Swarobright.

Hi John,

Many thanks for gathering all that together!

Just one correction. The AT/ST scopes did both use Porro, but in the AT version the Porro was followed by a semi-pentaprism for the 45º angle change. That prism does require mirror coating on one surface. On the other hand the ATS/STS series used Porro for the STS and a Schmidt (not Schmidt-Pechan) for the ATS. That one required P coating, but not mirror coating.

Henry