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Binocular Light Transmission Chart (1 Viewer)

Thank you very much! Unfortunately no mention of methodology... but they're not far off what one sees elsewhere.

Joachim
 
Dennis
Perhaps a major part of the reason that it is a good transmitter is that it is simple. After all, a bino with no glass in it at all will transmit 100%.

Lee
I agree. All the porro's are generally very good transmitters, especially if they have good updated coatings on them. That is one advantage of a porro and they don't need any special HT glass to do it because they have LESS glass to absorb the light. Nice transmission chart. I wish it had more binoculars on it though.
 
I agree. All the porro's are generally very good transmitters, especially if they have good updated coatings on them. That is one advantage of a porro and they don't need any special HT glass to do it because they have LESS glass to absorb the light. Nice transmission chart. I wish it had more binoculars on it though.

Den

Don't forget our own Gijs has published transmission figures for many different binos here:
https://www.houseofoutdoor.com/verrekijkers/verrekijkers-testen-en-vergelijken/

Lee
 
Lee/Dennis,

Don't forget this data simply tells you about the normalised signal distribution between the 3 colour channels of a Canon D400 camera. It tells us absolutely nothing about the peak or average transmission levels.

David
 
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.... a little voice in my head wonders about uncertainties... without those a comparison is not meaningful. Of course if we are comparing apples to potatoes then comparing will be less possible.

Peter
 
I recently found this binocular light transmission chart on a Russian website: http://astro-talks.ru/forum/viewtopic.php?f=7&t=2884 . An edited Google translation (sections not pertaining to binoculars and telescopes were deleted) is attached for those who may be interested.

Many thanks. The table appears to allow comparison of several models that I've been interested in over the years, including the old Nikon 8x30 and Swift Audubons.

Was there text to describe how the measurements were taken, equipment, etc.?

Ed
 
Dennis, post 7,
Your statement of the high inherent transmission of porros is not correct. We find very high transmissions for the newest Habicht porros and very low ones for older porros even as low as 50% or even less.
Gijs van Ginkel
 
Lee/Dennis,

Don't forget this data simply tells you about the normalised signal distribution between the 3 colour channels of a Canon D400 camera. It tells us absolutely nothing about the peak or average transmission levels.

David

A timely reminder David, thank you.

Lee
 
Dennis, post 7,
Your statement of the high inherent transmission of porros is not correct. We find very high transmissions for the newest Habicht porros and very low ones for older porros even as low as 50% or even less.
Gijs van Ginkel

Gijs
Presumably those old porros had no coatings or very inefficient coatings.

Lee
 
Lee,
Even the older ones with coatings have sometimes quite a bit lower transmission.
Gijs
Gijs,
"Even the older ones with coatings have sometimes quite a bit lower transmission."

What would you attribute that to? Why would the Habicht transmit better than the older porro's with coatings? Newer better coating's or glass? Thanks!
 
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Some old binoculars have yellowing balsam, possibly yellowing glass and haze on the glass surfaces.
In addition some of the glass was originally grey or dirty with imperfections.
The Barr and Stroud WW2 binoculars were made with best Scottish sand, which wasn't very clear and known to be a dirty grey colour.

Quite modern, probably Chinese, Bresser 15x60 binoculars that I have also have grey glass. I consider them to be only useful as paper weights or to keep the door open.

In addition old glass can devitrify and eventually become opaque.

Although old binoculars may be dismantled and cleaned, I am not convinced the dirty layers are always removed.

Some old Leitz camera lenses are notorious for becoming less transparent with age.
Different glass types behave differently.

Lead crystal vases are 24% lead and very grey. They are like this because cutting this glass is easy.

Quite many Broadhurst Clarkson telescopes and magnifying glasses have green glass when looked at sideways through the glass.
Some were made with plate glass window remains. This used to be collected after bombing raids.
They also kept six English house spiders to provide thread for their filar micrometers.

B.
 
Some old binoculars have yellowing balsam, possibly yellowing glass and haze on the glass surfaces.
In addition some of the glass was originally grey or dirty with imperfections.
The Barr and Stroud WW2 binoculars were made with best Scottish sand, which wasn't very clear and known to be a dirty grey colour.

Quite modern, probably Chinese, Bresser 15x60 binoculars that I have also have grey glass. I consider them to be only useful as paper weights or to keep the door open.

In addition old glass can devitrify and eventually become opaque.

Although old binoculars may be dismantled and cleaned, I am not convinced the dirty layers are always removed.

Some old Leitz camera lenses are notorious for becoming less transparent with age.
Different glass types behave differently.

Lead crystal vases are 24% lead and very grey. They are like this because cutting this glass is easy.

Quite many Broadhurst Clarkson telescopes and magnifying glasses have green glass when looked at sideways through the glass.
Some were made with plate glass window remains. This used to be collected after bombing raids.
They also kept six English house spiders to provide thread for their filar micrometers.

B.


Thanks Binnie

Lee
 
Dennis, post 16,
I have looked in our files and between the different porros made between 1945 and 1980 by different companies (e.g. Beck, Bush, Goerz, Kern, Möller, Voigtländer, Wöhler, Wollensak, Bausch and Lomb, Leitz, Zeiss, Krombach, Minolta, Pentax, Hertel & Reuss, Nickel,, Nitschke, Swarovski , Bleeker, Oude Delft-Delft Instruments, Tento, Komz, Konica) between 1945 and 1980 quite a few had transmissions from below 50% up to 80% and all values in between.
As Binastro in his post 18 already has explained a number of factors can be the cause of it.
Gijs van Ginkel
 
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