% light transmission: a canard? (1 Viewer)

[Owlbarred]

Despite the data for the models below, I've seen a statement on BF that the Nikon is dimmer than the Zeiss. If so, then the manufacturer-provided data are misleading or there is more than meets the eye. I'm confused.

Model.................. % light transmission
Zeiss SLF 10x40............. 90%
Nikon HG 10x42............. 92%

 

[Ted Y.]

Despite the data for the models below, I've seen a statement on BF that the Nikon is dimmer than the Zeiss. If so, then the manufacturer-provided data are misleading or there is more than meets the eye. I'm confused.

Model % light transmission
Zeiss SLF 10x40 90%
Nikon HG 10x42 92%

I trust the manufacturers.
What method was used to compare the binoculars?

 

[Canip]

I've seen a statement on BF

Well, there are lots of statements on BF, and not all of them need to be trusted …

 

[has530]

Also just one number for light transmission doesn't tell the whole story. Each will transmit differently at different wavelengths. It may be that the zeiss has higher transmission in a certain part of the spectrum that makes them appear brighter (for me the cool image of great short wavelength light in searovski SLCs has always seemed very bright even if they didn't have the highest transmission). Also comes down to individuals sensitivities to different wavelengths and lighting conditions of their test et cetera.

Realistically the eye can't even really discern a 2% difference in transmission so I wouldn't worry about it. But then again I am in the "coatings are overrated" camp and regularly use older binoculars without modern multicoatings and get along just fine with them.

 

[Ignatius]

Also just one number for light transmission doesn't tell the whole story. Each will transmit differently at different wavelengths. It may be that the zeiss has higher transmission in a certain part of the spectrum that makes them appear brighter (for me the cool image of great short wavelength light in searovski SLCs has always seemed very bright even if they didn't have the highest transmission). Also comes down to individuals sensitivities to different wavelengths and lighting conditions of their test et cetera.

This is shown by the transmission curves one can find in the Mr. van Ginkel's tests. It is only natural to assume, that manufacturers publish the highest number attained on the spectrum in order to look good. Presumably it would be more honest to state that number in the form of "up to x%".

 

[wllmspd]

Are they publishing the peak or the weighted average for a given illuminant spectrum and the human CIE observer response? It could be that for different scenes (with different colour balances) different binoculars could appear differently bright with respect to each other.

Peter

 

[GrampaTom]

Read Gils on "House of Outdoors"

 

[Owlbarred]

Good stuff. Thanks for the replies.

 

[Owlbarred]

Thanks for the reference to Gijs van Ginkel's comprehensive treatise on binoculars:
COLOR VISION, BRIGHTNESS, RESOLUTION AND CONTRAST IN BINOCULAR IMAGES.

The section addressing brightness is attached in the link below (reference p. 21)
6. Brightness, luminance and color

 

[quincy88]

Representing light transmission as a single value seems meaningless to me.

 

[Maljunulo]

Why?

 

[quincy88]

Because humans see a spectrum of wavelengths and optics transmit those wavelengths at different rates.

 

[Maljunulo]

They eye is not a spectrograph, we see all the wavelengths simultaneously.

 

[MiddleRiver]

I believe Quincy meant at different intensities, not non-simultaneously.

 

[Maljunulo]

Also, I'm not at all sure what "transmit those wavelengths at different rates" means.

I'm not following very well here.

 

[MiddleRiver]

Go look at one of Gijs spectrum/transmittance graphs.
"transmit those wavelengths at different rates" means that 500nm wavelength might xmit at 90% rate, while 600nm at only 85%. It's not ONE value. It's a curve and some wavelengths get through at high rates and others not so much. So the point is that to say one bino xmits 90% and the other one 87%, is meaningless unless you compare the curves, consider eye sensitivity, etc.

Are transmission graphs relevant for you when selecting binoculars? How?

Any science or measurement that shows how a bino/telescope works compared to others is interesting and will attract my attention. Then comes the collimation of facts and figures and not least the testing (if possible). I bought my habichts partly based on transmission data (but with maker and...

www.birdforum.net

You seem to have participated in several of these conversations in past. I'm not sure what's confusing you know, unless you are just quibbling with language or trying to get a rise out of Quincy and others?

Am I missing something?

 

[Maljunulo]

Go look at one of Gijs spectrum/transmittance ]
You seem to have participated in several of these conversations in past. I'm not sure what's confusing you know, unless you are just quibbling with language or trying to get a rise out of Quincy and others?

Am I missing something?

No, I am not "trying to get a rise out of Quincy" or anyone else.
As for "quibbling over words" I guess it's just a matter of usage, and style of expressing oneself. Sometimes folks say things in a way which confuses me, and I ask for clarification, or to say the same thing differently, so I am sure I know exactly what they are talking about.

Rate: a quantity, amount, or degree of something measured per unit of something else.

This definition does not add a whole lot of clarity to me. In any event, I would never call a percentage a rate, so it confused me.

I hope that I have addressed your comments/accusations to your satisfaction.

 

[quincy88]

Go look at one of Gijs spectrum/transmittance graphs.
"transmit those wavelengths at different rates" means that 500nm wavelength might xmit at 90% rate, while 600nm at only 85%. It's not ONE value. It's a curve and some wavelengths get through at high rates and others not so much. So the point is that to say one bino xmits 90% and the other one 87%, is meaningless unless you compare the curves, consider eye sensitivity, etc.

Are transmission graphs relevant for you when selecting binoculars? How?

Any science or measurement that shows how a bino/telescope works compared to others is interesting and will attract my attention. Then comes the collimation of facts and figures and not least the testing (if possible). I bought my habichts partly based on transmission data (but with maker and...

www.birdforum.net

You seem to have participated in several of these conversations in past. I'm not sure what's confusing you know, unless you are just quibbling with language or trying to get a rise out of Quincy and others?

Am I missing something?

Thanks MiddleRiver. Exactly what I meant.

 

[quincy88]

No, I am not "trying to get a rise out of Quincy" or anyone else.
As for "quibbling over words" I guess it's just a matter of usage, and style of expressing oneself. Sometimes folks say things in a way which confuses me, and I ask for clarification, or to say the same thing differently, so I am sure I know exactly what they are talking about.

Rate: a quantity, amount, or degree of something measured per unit of something else.

This definition does not add a whole lot of clarity to me. In any event, I would never call a percentage a rate, so it confused me.

I hope that I have addressed your comments/accusations to your satisfaction.

Percentage: a rate, number, or amount in each hundred.
Not sure about the language. MiddleRiver elaborated nicely on what I was saying.

 

[MiddleRiver]

With @Gijs van Ginkel kind permission and standing on the shoulders of House of Outdoors fantastic work, I present my quick-and-dirty photochop attempt to make (a little better) sense of graphs. Note that I've tried my best to stretch and scale screen-clips from the PDF reports, but this is in NO WAY meant to be a scientifically rigorous effort.

That said, I think it demonstrates that data wout context (i.e. what we often argue over on optics forum) is a poor way to select bins. No one would argue that the SF's aren't top-tier. Yet see how they drop off above 625nm or so and 'compare poorly' to others including the Terra's! But as has been pointed out in other threads, 'does it matter??' - the eye's sensitivity declines precipitously above that same spot (and don't forget that the curve gets notably worse as we age!).

If anyone sees glaring errors, please lmk asap!