Telson Optics - 99.8% Light Transmission?!?

Unfortunately, there is no standard way of spec'ing it. Some companies talk about transmission per surface. Some talk about transmission through the whole scope, but neglect to mention the wavelength range. I have seen companies average it for a particular color. I have seen companies only provide the number for a single wavelength where it looks the best for them. There is really no standardization there.

The simplest way is to do what Telson did. Whoever does lens coating for them gives them a spec per surface and this what they used. To do anything meaningful beyond that will require some relatively specialized equipment.

The way we do it in the lab is spectral transmission, but you can't meaningfully reduce it to a single number. It is a graph. Even then, depending on where in the entrance pupil you do the measurement and at what magnification and erector position, you can easily get a different answer.

ILya

KevinWood44 said:

Interesting. I hadn't even considered that the wavelength range would effect it so much. I guess I assumed all companies used a standardized metric.

So if it's measured so ambiguously (or in this case completely differently) why is it used at all??

Click to expand...

Because bigger numbers give the "impression" it is better. So if most German companies use one method that gets transmission rates around 90-93% and then another company uses the surface method like what Telson is doing here it gives the impression that your Telson scope is much brighter than most other scopes. Different glass and different multi-coating is like the Transformers... "there's more than meets the eye"

Glassaholic said:

Because bigger numbers give the "impression" it is better. So if most German companies use one method that gets transmission rates around 90-93% and then another company uses the surface method like what Telson is doing here it gives the impression that your Telson scope is much brighter than most other scopes. Different glass and different multi-coating is like the Transformers... "there's more than meets the eye"

Click to expand...

The way this usually works with single number specs is the same in all industries. Some marketing guy comes up with a number he does not understand and uses it. Then all of his competitors have to put a number or some gullible customer is going to complain. Then someone stars yelling that everyone's number is bullshit and only his number is correct (without providing context).

Then various consumers will pick a company they like and start yelling at each other and at companies they do not like that everyone else's number is wrong (somewhat along the lines of what both of you are doing in this thread, to be entirely honest).

Usually, all of the numbers are accurate, but meaningless without context and background information.

As far spectral aspect of it, here is a simulated transmission plot for a Japanese scope designed about a decade or so ago. This was a very nice scope (although its replacement is even better), but you can see the transmission different between blue and green.



In the grand scheme of things, for modern mid to high end riflescopes, light transmission should be the last thing you worry about. It has been reasonably commoditized. A manufacturer would have to be functionally retarded to not be able to find a good coatings supplier.

Interestingly, the reflections, for many designs, make a bigger difference than overall transmission since the reflected light strength plays directly into flare handling (together with baffling).


ILya

koshkin said:

The way this usually works with single number specs is the same in all industries. Some marketing guy comes up with a number he does not understand and uses it. Then all of his competitors have to put a number or some gullible customer is going to complain. Then someone stars yelling that everyone's number is bullshit and only his number is correct (without providing context).

Then various consumers will pick a company they like and start yelling at each other and at companies they do not like that everyone else's number is wrong (somewhat along the lines of what you are doing, to be entirely honest).

Usually, all of the numbers are accurate, but meaningless without context and background information.

As far spectral aspect of it, here is a simulated transmission plot for a Japanese scope designed about a decade or so ago. This was a very nice scope (although its replacement is even better), but you can see the transmission different between blue and green.

View attachment 8609520

In the grand scheme of things, for modern mid to high end riflescopes, light transmission should be the last thing you worry about. It has been reasonably commoditized. A manufacturer would have to be functionally retarded to not be able to find a good coatings supplier.

Interestingly, the reflections, for many designs, make a bigger difference than overall transmission since the reflected light strength plays directly into flare handling (together with baffling).


ILya

Click to expand...

I love it when you geek out on me like this