Binocular Light Transmission Chart (1 Viewer)

Dennis

I’ve picked a couple of illustrations to clearly show the differences in the number of air-to-glass surfaces

1) The 8x30 Deltrintem - the optical construction is the same as that of both Swarovski’s Habicht 8x30 W and 10x40 W
The first image is from the 1952 Carl Zeiss Jena catalogue (it also clearly shows the 90 degree offset of the 2 Porro prisms to correctly orientate the image)
The second is an x-ray image from Arek at Allbinos
(for both images see: https://www.allbinos.com/170.1-article-Legendary_binoculars_-_Carl_Zeiss_Jena_Deltrintem_8x30.html )

They both show:
7 lenses in 4 groups, plus 2 seperate prisms, for a total of 12 air-to-glass surfaces

EDIT: in contrast to the Zeiss, both the Habicht 8x30 W and 10x40 W have a 6 element eyepiece - 3 pairs in 3 groups - for a total of 8 lenses in 4 groups
However, the number of air-to-glass surfaces in the Zeiss and Habicht remain the same. See Henry's post #46 below


2) The EL Swarovision
This cross section is from the Swarovision patent

It clearly shows:
10 lenses (sic) in 8 groups, plus 2 seperate prisms, for a total of 20 air-to-glass surfaces *

So the EL SV has 12 glass components per side - 10 lenses and 2 prisms, vs the 12 air-to-glass surfaces of the Habicht

* as I previously indicated there’s an error in this illustration - one of the lenses in the eyepiece assembly has not been shaded in - so only 9 of the 10 lenses are are visible
see https://www.birdforum.net/showpost.php?p=3843650&postcount=10
However, as the missing lens is part of a cemented doublet it does not effect the number of air-to-glass surfaces, and otherwise the illustration is easy to follow


Also as previously indicated in this thread, there are of course additional transmission considerations including:
- the volume of glass along the optical axis;
- the type of glass (optical density and dispersion), and;
- coating efficiency (of anti-reflective coatings on all air-to-glass surfaces, plus phase and dielectric coatings on the non-Totally Internal Reflection surfaces of Schmidt-Pechan roof prisms)


John

John

Thanks, for that explanation. Nice cutout pictures. Very interesting! The light pathway through the Habicht looks so efficient. Is the Habicht more efficient than the EL because they are porro's and the EL's are roof's and porro prisms are totally internal reflective and roofs are not and they also have to be phase coated. I can't believe how much simpler a porro is versus a roof prism. NO WONDER they transmit better if properly coated and use good quality glass. I am liking porro's better all the time!

When comparing Porro I prism and roof prism binocular light transmissions it should be noted that Schmidt-Pechan roof prism systems have 6 internal reflections whereas Porro I prism systems have 4 internal reflections (Abbe-Konigs, though, have 4). This gives the Porro I system (and A-K as well) slightly more light transmission than the S-P system. However, I believe this difference in light transmission is slight (3%?) and in practical terms may not be noticeable to the user.

LPT said:

This gives the Porro I system (and A-K as well) slightly more light transmission than the S-P system. However, I believe this difference in light transmission is slight (3%?) and in practical terms may not be noticeable to the user.

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True but to a product development programme the AK prisms give a nice platform to add other transmission improvements to and create a perceptible difference.

Lee

LPT said:

When comparing Porro I prism and roof prism binocular light transmissions it should be noted that Schmidt-Pechan roof prism systems have 6 internal reflections whereas Porro I prism systems have 4 internal reflections (Abbe-Konigs, though, have 4). This gives the Porro I system (and A-K as well) slightly more light transmission than the S-P system. However, I believe this difference in light transmission is slight (3%?) and in practical terms may not be noticeable to the user.

Click to expand...

Good explanation of the three prism's the SP, AK and Porro and their relative light transmission efficiencies.

Here's a cutaway of the 10x40 W Habicht below. The 8x30 W is identical except for a shorter objective tube and smaller objective lens. The only significant difference between the Habicht and Zeiss Deltrintem eyepieces is the use of a 6 element modified Erfle from 1923 in the Habicht vs the original 1917 5 element Erfle in the Deltrintem.

The Swarovski transmission graft below comparing a 1999 EL (14 surfaces) and a 2012 EL SV (20 surfaces) shows just how much could be accomplished by upgrading coatings even while adding more glass surfaces.

Henry and John. Where do you guy's find all those historical pictures and cutaways. Really nice! Your picture of the Habicht Henry shows just how simple the design is. That graph on the comparative transmission of the older EL's and the newer Swarovision is amazing how much coatings improved the transmission even with more glass in the binocular. i just don't get it how many lenses are needed in a modern binocular like the Swarovision and it is amazing ANY light at all get's through all that glass. I guess that is a testament to how efficient those coatings are.

Henry

Good catch with the distinction between the two Erfle versions (5 vs 6 lens)
I went with the Zeiss photos for the extra clarity of showing the number of air-to-glass surfaces, though of course the Habichts are the 6 element version - a bit of brain fade on my part!

Thanks
John

I asked Swarovski why the Habicht has such high light transmission values of 96% and this was their answer.

"Hello Mr. Mau,

There are many factors that go into a final light transmission percentage. The two most influential are the amount of lenses in any optical system and the types, number of layers and effectiveness of the anti-reflective coatings.

Each lens blocks a certain amount of light. On average, each "uncoated" air to glass surface (or each side of one lens) would block about 5% of the light passing through. Once our trademark SWAROTOP and SWARODUR coatings are applied to the air to glass surfaces, the percentage of light blocked is reduced to 2/10ths of 1% or 0.2% for each air to glass surface.

There are also hundreds of glass types and qualities that are available to any optic maker. Swarovski uses ONLY the top grades that yield an exceptionally clear high resolution view. These high quality lenses are also more expensive. This high quality glass with the coating technology we have makes Swarovski binoculars what they are.

The prisms also make a difference. Porro prisms can transmit more light than Roof prisms. But mainly, the porro prism design requires less glass in the entire optical system than roof prism designs. Therefore more light transmission.

We use two styles of roof prisms in our roof prism binoculars: Schmidt-Pechan or Abbe-Koenig. The Abbe-Koenig transmits more light, but that doesn't necessarily mean that an individual Abbe-Koenig prism binocular will have a better overall "view" over a similar magnification and objective size Schmidt-Pechan design. It all depends on the entire optical system of any given binocular.

Another consideration: Whether Porro or Roof Prism, a personal choice as to what is preferred. Roof prisms have the advantage of a more compact and more rugged design. Porro prisms have always had the reputation for a greater depth of field. As far as demand goes, Swarovski Optik no longer stocks Porro Prism design binoculars in the U.S. but offers them as a special order. Nowadays, our customers by far prefer the roof prism designs.

I could be wrong, but I am quite confident that if you were to compare and choose between our 10x42 EL (90% light transmission) roof prism to our 10x40 Habicht (96% light transmission) porro prism, you would choose the overall view and handling characteristics of the 10x42 EL. In the end it is the entire optical system that makes the difference. Light transmission is just one value to measure the performance of an optical instrument."

Best regards,

Tom Hogan


-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Sunday, May 26, 2019 9:42 AM
To: Swarovski Optik <[email protected]>
Subject: Contact Mail - Swarovski Optik Online Shop

To SWAROVSKI OPTIK Customer Service
+++++Subject +++++
Light transmission In Habicht porro binoculars versus EL roof prism binoculars.
+++++ Following message +++++
Why do the Habicht Porro Prism binoculars have such high light transmission values of 96 % and the EL Roof Prism binoculars only have about 90%? I have heard they have the same glass and coatings. Is it due to the difference in the prism's? This is a question for your technical department. Thanks!
+++++ Name +++++
Dennis W Mau
+++++ Contact information: +++++
Email: [email protected]
Telephone: 3033325112
Country:
United States of America (USA)
This email has been automatically generated by the SWAROVSKI OPTIK Online Shop.

Transmission of light

etudiant said:

The Zeiss Jena DF7x40, aka the Checkpoint Charlie glass, standard issue for the East German Army, is famous for its relaxed and easy view, but has only about 60% transmission. So I think there are a lot more important factors in selecting a glass than a few percent difference in the transmission ratio.

Click to expand...

This is so true and I still enjoy the view through the 7X40 DF.

Andy W.

jring said:

Unfortunately no mention of methodology...
Joachim

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There is detailed explanation with pictures:
original: http://astro-talks.ru/forum/viewtopic.php?f=3&t=2799&p=54991#p54811

in Google translate:
https://translate.google.com/transl...forum/viewtopic.php?f=3&t=2799&p=54991#p54811

The main measurement equipment is DSLR Canon 400d. It allows to make measurement through the color filters of the Bayer matrix on the chip of the Canon Eos. And there are some measurements through narrow band filters (Baader SC, Lumicon OIII and H-beta) are also available. It is not quite the common wavelength of RGB of a human eye. But better than nothing.

I believe that all data are correct and useful.

:cat:“Stacking BBs all night long ... ‘daylight come and me wan go home.” — Harry Belafonte, 1956

Okay, so I took some liberties ... again.

These light transmission threads can be useful if the whole picture is understood.

1. Zeiss’ Alexander Smakula developed the vacuum method of coating optics in 1935. Still, in the early 1940s, light transmission in Porros ranged from 50% to 66%. The 66% was achieved by Bar & Stroud’s cemented prisms—let’s hear it for the Brits. Taking advantage of mag fluoride coatings, light transmission jumped to 85%, then 87% and continued to climb.

2. Not all binocular firms are created equal. I will admit I have NOT read all the entries in this long thread. However, scanning through I see a lot of pertinent information. LPT’s post #25 is a good example. To it, I would add SURFACE SMOOTHNESS—something too often overlooked.

3. While discussing the need for photometer use with a friend and CEO of a large optical firm, I heard:

“That would probably keep you in a courtroom the rest of your life because companies would contest anything you said or printed that didn’t put them in a good light. No matter what you said, you would be up against ‘Yeah, buts.’ And, too, the data could be interpreted in different ways by different people. You might think you nailed it down. But, really, all you would be doing is opening a can of worms.”

4. After one of my binocular articles, a representative of a major binocular company intimated it would be financially beneficial to me to come up with a transmission chart illustrating his company’s binocular coatings were superior to a handful of coatings of other industry legends. Basically, he wanted me to put my name behind a lie. Were their coatings very good? Oh, yeah! Were they NOTICEABLY better than those of their peer companies? They were not? Could the average observer tell the difference? No. Good advertising need not be accurate or even meaningful, it has only to be believed. To be followed by my mother’s quote, “Figures don’t lie, but liars figure.”

5. Finally, graphic artist and desktop publishers can modify the results of those test without trying or even meaning to.

With those things taken into consideration, I think it can be seen that even using a photometer and publishing the results can be glorious effort ending in futility.

Bottom line:

Buy a binocular that costs more than a pet rock. If it does what you want, use it. If you SEE A REASON to change, reach deeper into your pocket and buy another.

I am amazed at the people who use some of the best binoculars ever made and consistently talk about “upgrading” ... optically. Weight? Yes. Ergonomics? Yes. Style? Maybe. But optical performance? Very rarely. As I have pointed out before, most of the differences in performance people claim to be seeing are demonstratively below a human's proven ability to see. 'Talk about? No. See? Yes. When there is a major upgrade available, like going from non-coated optics to coated optics, or single layer mag fluoride optics to multicoated optics? Yes. But so many people latch onto beliefs about certain things being noticeably “better” when that belief is based on several other things coming together and being misinterpreted by the observer. Perception is not reality. Although it can certainly make the observer happy.

Select a bino for the task at hand. Besides, killdeers like to walk, requiring much less movement than watching Pterodactyls, who like to perch and whose "flitting from one limb to another" might require a 5-mile hike.

Bill

Hi guys! I hope the "Light Transmission Chart" will be interesting for you. If you have questions, I will be happy to answer them. I apologize for my English, this is mostly a Google translation.

As for the technique, almost at the very beginning of the measurements, it underwent slight changes. It turned out that the small distance from the binoculars to the diaphragm introduces some error associated with the light scattering on the glass surfaces. In the worst case light scattering adds up to ~ 1.5% to light transmission. Therefore, the table shows the values ​​obtained when installing binoculars at a distance of about 0.5 m from the luminous surface.

I would also like to note that each of the binoculars subjected to the tests I carefully study visually. And there was not a single case when the data of instrumental measurements diverged from visual impressions. Both indicators, light transmission and color rendition, have a very good correlation with the image brightness, color tone and its "intensity" (in quotes, because actually there is no such physical term).

Best regards, Oleg Novikov.

Hi Henry!

henry link said:

The Nikon SE and EII have six element eyepieces, but in a more modern 4 group design...

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In the X-ray image of the Nikon 8x30 EII from this article we can see that the eyepiece design has 5 elements in 3 groups.

henry link said:

The Swarovski Porros with the fewest surfaces were the 7x42, 7x50 and 8x56 SLs with 3 element, 2 group Konig eyepieces and cemented prisms...

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Don’t know how Habicht was in the past, but in modern 7x42 prisms are not cemented. Please watch this material.

traveller in time said:

Hi Henry!


In the X-ray image of the Nikon 8x30 EII from this article we can see that the eyepiece design has 5 elements in 3 groups.


Don’t know how Habicht was in the past, but in modern 7x42 prisms are not cemented. Please watch this material.

Click to expand...

Hi Traveller,

I also thought the E II eyepiece was 5 elements in 3 groups when I first saw the X-ray in the Allbinos article. Arek supplied a better X-ray image of the eyepiece which makes it clear that it's really 6 elements in 4 groups. See the exchange between us in posts #19-22 in the thread below.

https://www.birdforum.net/showthread.php?t=310231

The Swarovski Porro series with cemented prisms I referred to was the SL series. See the cutaway below.

Henry

henry link said:

Hi Traveller,
Arek supplied a better X-ray image of the eyepiece which makes it clear that it's really 6 elements in 4 groups. See the exchange between us in posts #19-22 in the thread below.

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Many thanks!! I was puzzled so long, why the reflections from the eyepiece is 2 more than it should be)))

henry link said:

The Swarovski Porro series with cemented prisms I referred to was the SL series. See the cutaway below.

Click to expand...

Oh, I apologize for my carelessness. I did not pay attention to the "SL" in your post and forgot that swarovski have been made other porros besides Habicht.

Who uses what kind of binoculars for bird watching? Selecting binoculars is a lot like tasting wines. It takes most people years of experience to be able to notice subtle differences in quality and articulate preferences using just the right lingo. Personal preference plays a large role in picking favourites. I usually read reviews on places like http://huntingfishingplus.com/best-hunting-binocular/ or any good review site. You could sip one of the world’s finest chardonnays and dislike the smooth, buttery finish derived from the oak barrels. In the same way, you might turn your nose up at the open-bridge design of a pair of top-of-the-line Swarovskis, a feature adored by many. Really does depend on your style.

Blackswanasa said:

Who uses what kind of binoculars for bird watching? Selecting binoculars is a lot like tasting wines. It takes most people years of experience to be able to notice subtle differences in quality and articulate preferences using just the right lingo. Personal preference plays a large role in picking favourites. I usually read reviews on places like Amazon or any good review site. You could sip one of the world’s finest chardonnays and dislike the smooth, buttery finish derived from the oak barrels. In the same way, you might turn your nose up at the open-bridge design of a pair of top-of-the-line Swarovskis, a feature adored by many. Really does depend on your style.

Click to expand...

I think Bill learnt his trade in a large very hierarchical organisation. All his points are fully valid, but civilian life also has strange rites based on form and color, not only function. As most of our wives will explain to us though, all shoes are not equal just because they fit

Edmund

After just purchasing a Swarovski Habicht 7x42 I confer on the high light transmission. It is a very bright binocular and performs very well under low light. Also, it is very light for a 42mm.

eronald said:

I think Bill learnt his trade in a large very hierarchical organisation. All his points are fully valid, but civilian life also has strange rites based on form and color, not only function. As most of our wives will explain to us though, all shoes are not equal just because they fit

Edmund

Click to expand...

Which is why I said: "Weight? Yes. Ergonomics? Yes. Style? Maybe. But optical performance? Very rarely."

I covered my bases. :cat:

Bill