Zeiss Diavari still king of low light?

Lancaster said:
Looks sort of familiar is it the mainland, or is it Seil, Luing or another of the Slate Islands?
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Just a couple of miles north of the Bridge over the Atlantic onto Seil, top of the cliffs at Duarchy looking over the big collapsed bowl of boulders, 500m to the sea.
We’re probably lying on The Toad (as seen from the north) and Eagle Rock is about 100m to the left.….my favourite perch for keeping watch over the bowl. 😎

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Dowhill from Eagle Rock…..wouldn’t mind my ashes being spread up there, and I doubt I’m alone in that…. 🤣

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My first memory from some 30years ago on our first visit with my Dad, I was placed on top of the last bit of white cliff in the mist to watch for anything that might stir below. I had no idea of the view until the sun burnt the mist off to reveal the fantastic vista with a couple of fishing boats chugging along and topped off with fighter jets hunting through at sea level 😳

The icing on the cake was a killer roebuck with a pair of spikes for a head with Dad’s BSA CF2 .222. He was on the next vantage point round.

cheers

fizz
 
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I'd have to say the ziess ht and s&b polar are better then the davari or tho I have a massive love for them and would like a 4-16×50 my self buy in terms of low light those two edge it for me
 
T* Diavaris are amazing and some of the brightest on the market

However the S&B T96 Polar is the current market leader for light transmission

Someone asked if the difference it can be seen by humans.
Some may
Some may not

The 72mm objective is an interesting point

It doesn’t change light transmission of the optics
It does give a much wider field of view which in turn appears brighter as there is more of it!
Its not brighter

You can’t compress natural light to improve transmission with a bigger funnel
Its not water

One thing people dont consider is the coatings various manufacturers use that suit some eyes and not others.
Look at the colours on the objectives.

Ruby on Diavari
Green on some Swarovski
Yellow on older Swarovski
Purple on S&B

Everyone has different eyes
Perception of clarity and best brightness is in the eye of the beholder…..
Literally


Except when down to pure scientific tests which are standardised
 
I find the reticule is critical as well. Plenty of scopes become very hard to use in low light because the reticule becomes too indistinct. Almost all modern high mag variable scopes have this problem, unless they have an illuminated reticle.

Old school heavy No. 4 reticules and similar make all the difference as the light goes.

Very hard to beat the S&B Klassik 8x56 right on the edge of dark and beyond. Shot bunnies by starlight with it.
 
Edinburgh Rifles said:
The 72mm objective is an interesting point

It doesn’t change light transmission of the optics
It does give a much wider field of view which in turn appears brighter as there is more of it!
Its not brighter

You can’t compress natural light to improve transmission with a bigger funnel
Its not water
Click to expand...
Sorry but this is crap. You can crank the magnification up with 72mm, to get same exit pupil. Everybody has a maximum (diminishing with age) that their pupil can achieve (and of course you have to be in dark like 30min before pupil has enlarged to the maximum).

With every scope, the picture will look brighter when the mag is down. Years and years ago there was a debate, what do you gain by going up in the mag. Because the amount of light coming through the scope is same for all mags. I think it was caorach (my memory might fail) that summed it up, when mag is up percentually more of that light is coming from your target, i.e. you get more info on the target.

Accepted value for youg people's max pupil is 7mm. So you could crank the mag to 56mm/7mm=8x or 72mm/7mm~=10x in respective lens sizes (and still get theoretical maximum usable exit pupil). In practice, when you want to look for detail like antlers, the sweet spot is maybe 20% higher (brightness goes down but you still gain detail). This is situation dependent, and assumed that your eyes have adapted for max. pupil. If you think something like UK "last light", your eyes have never reached the max. pupil so you can go even higher in mag if desired.

Haven't looked at 56mm vs. 72mm Diavaris optical design so cannot comment on FOV. BTW T* only means that there is some generation of T coatings. I don't remember the generations, but basically they first had T1 and so on. So T* only means the coatings are top notch when compared to scopes of the same age. 30y old T* is inferior to T* of today.
 
jthyttin said:
Sorry but this is crap. You can crank the magnification up with 72mm, to get same exit pupil. Everybody has a maximum (diminishing with age) that their pupil can achieve (and of course you have to be in dark like 30min before pupil has enlarged to the maximum).

With every scope, the picture will look brighter when the mag is down. Years and years ago there was a debate, what do you gain by going up in the mag. Because the amount of light coming through the scope is same for all mags. I think it was caorach (my memory might fail) that summed it up, when mag is up percentually more of that light is coming from your target, i.e. you get more info on the target.

Accepted value for youg people's max pupil is 7mm. So you could crank the mag to 56mm/7mm=8x or 72mm/7mm~=10x in respective lens sizes (and still get theoretical maximum usable exit pupil). In practice, when you want to look for detail like antlers, the sweet spot is maybe 20% higher (brightness goes down but you still gain detail). This is situation dependent, and assumed that your eyes have adapted for max. pupil. If you think something like UK "last light", your eyes have never reached the max. pupil so you can go even higher in mag if desired.

Haven't looked at 56mm vs. 72mm Diavaris optical design so cannot comment on FOV. BTW T* only means that there is some generation of T coatings. I don't remember the generations, but basically they first had T1 and so on. So T* only means the coatings are top notch when compared to scopes of the same age. 30y old T* is inferior to T* of today.
Click to expand...

You seem to repeat what I said, just with more words and bringing exit pupil diameter into it which limits what we can use not the capability of the glass
“Picture looks brighter, but you have the same light transmission “
Nowhere does magnification come into it when comparing light transmission of optics
 
Edinburgh Rifles said:
You seem to repeat what I said, just with more words and bringing exit pupil diameter into it which limits what we can use not the capability of the glass
Click to expand...
I don't know what you were trying to say, but in effect you said that 72mm doesn't gather any more light [than smaller objective].

In fact you said (implied) that anything larger than internal lenses in the main tube doesn't gather any more light, since you cannot "compress" light.

And regarding compression, water is known to compress very little (as also other liquids). You just have your physics upside down at moments, and try to cling on your opinions and present them as facts.

Yes light transmission is a number (actually set of numbers, because it's different on all wavelengths) that tells you what percentage of light entering the system will pass through. This number might be even higher for smaller lenses, since it's easier to manufacture them with fewer flaws.

But discussion is about low light performance, where surprise surprise people want to use magnification, and that is tied to front lens size. Bigger lens equals more usable magnification, and that equals more information about your target.

If you're satisfied with, say 6x, there's no physics based benefit to go larger than 42mm objective. And for bit older eyes, you could easily drop that to 36mm.
 
jthyttin said:
I don't know what you were trying to say, but in effect you said that 72mm doesn't gather any more light [than smaller objective].

In fact you said (implied) that anything larger than internal lenses in the main tube doesn't gather any more light, since you cannot "compress" light.

And regarding compression, water is known to compress very little (as also other liquids). You just have your physics upside down at moments, and try to cling on your opinions and present them as facts.

Yes light transmission is a number (actually set of numbers, because it's different on all wavelengths) that tells you what percentage of light entering the system will pass through. This number might be even higher for smaller lenses, since it's easier to manufacture them with fewer flaws.

But discussion is about low light performance, where surprise surprise people want to use magnification, and that is tied to front lens size. Bigger lens equals more usable magnification, and that equals more information about your target.

If you're satisfied with, say 6x, there's no physics based benefit to go larger than 42mm objective. And for bit older eyes, you could easily drop that to 36mm.
Click to expand...
I think a lot of the confusion in these discussions comes from people thinking of light as a ‘stream’, when it’s actually more like rain. It’s not a continuous connected flow, it’s a scatter of disconnected particles. Fewer incoming particles, bigger bucket needed to catch some.

So a wider objective lense CAN collect more light and it CAN be condensed down to fit through a smaller internal lense. The ‘condensing’ is the focus.

The effect is asymptotic: as incoming light intensity increases, the objective lense approaches saturation, and that is where transmission to the eye starts to be limited by the internal lenses.

Hence telescopes used to look at the night sky benefit from the biggest possible objective lens, yet have an eyepiece no different from your rifle scope.
 
triggertrix said:
I’m not a believer in fixed last light. Most fixed are 7-8x in 50-56mm. Personally I find 4x with 56mm produces the best low light image
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I thought 7 was the max exit pupil size that the eye could use, eye e (ie) 8x 56 = 56 devided by 8 = 7.
Working on that formula a 4 x 56 wouldn‘t have any advantage.
I have been wrong before.
Cheers, Ken.
 
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kenbro said:
I thought 7 was the max exit pupil size that the eye could use, eye e (ie) 8x 56 = 56 devided by 8 = 7.
Working on that formula a 4 x 56 wouldn‘t have any advantage.
I have been wrong before.
Cheers, Ken.
Click to expand...
No, You’re correct, but winding the mag down when it’s getting dark definitely improves clarity in my zeiss
 
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