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This quote from forum member got me thinking? (1 Viewer)


Well-known member
Quote Below from a helpful forum member...which may explain why I didn't see an improvement in the conquest 10x40 with 93% transmission vs my 89% legend ultra hd, bc the zeiss have low transmission in the blue-green part of the spectrum

"high trasmission in the blue-violett spectrum seem to do a lot for contrast in low light, and probably also perceived brightness,
Swaro SV:s are good at that, also Zeiss HT and the new Leica HD Plus,

Older Zeiss (and also the bushnells it seems) have a high peak transmission in the yellow spectrum but falls quite steep in the green to blue spectrum"
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Well-known member
If there is haze or glare from glossy surfaces,
high transmission actually causes a loss of contrast.
It can look brighter, though, due to specular glare.
(direct reflection from a glossy surface)

However, most people could not tell the difference between 89% and 93%.
It would be interesting to see what is considered "quite steep", when the overall
transmission can be pretty high, since the late 1970s.

Makers like Zeiss often balance the rolloff in one end of the spectrum
with some losses in the other, so they are 'color-corrected' and appear nice and neutral.


Well-known member
Here is a quote off of Leupold's webpage:

" The Twilight Max Light Management System delivers the highest average light transmission in all colors with emphasis on the blue and red portions of the light spectrum for exceptional low light performance and contrast in all conditions."

It got me wondering how tweaking the light spectrum might effect performance, if at all, other than altering color rendition.

Is this just marketing mumbo jumbo or is there some substance behind this?



Well-known member
Fiddling the spectrum used to be popular in the 60s and 70s, for
things like hunting. Emphasizing both red and blue is confusing...
does that mean green is reduced??? Green is the eye's most sensitive
color by far. IT may be true but I don't know what they are targeting.


Well-known member
It is how they are selling a rifle scope that is new to market this year.... so for finding those monster bucks in the dark woods. I recall Steiner promoting an optic in a similar manner which was supposed to enhance the body color of the animal to make it stand out against its background.

I'm thinking if either had any merit, it would be industry standard for years already.



Well-known member
I use Scope amber-coats(no, not the severe metallic type) or Bushnell Customs
tracking deer and turkeys in the woods. It isn't so much that the brown comes through
as the grey-blue and shine on the limbs is lowered. It is easier to follow the deer especially,
and fisher-cats. IT does yellow things a little (in the Customs) or green them (Scope 10x35s).
It's simple violet reduction.


New member
Aging eyes

I have also read that as we age, our eyes become less sensitive to blue and above frequency. Perhaps there is something to think about with how to structure the spectrum transmitted to overcome this.


Well-known member
I think that the eye lens yellows with age, but those who had cataract surgery were able to see into the ultraviolet.
In WW2 elderly people who had surgery were used to read morse code messages across the English channel, I think, transmitted with wavelengths young people could not see.
I don't know if this applies to modern cataract surgery.

I once saw a very blue large lit sign and it really hurt my eyes to look at it.

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