Ingle1970
Well-known member
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New Zeiss HT's in 8 & 10x54 (1 Viewer)
- Thread starter Ingle1970
- Start date
Henry. You see those 8x54 Zeiss HT's. 95% transmission and the big Abbe-Konig prisms. Wow, those things would be bright at dusk!
Gijs van Ginkel
Well-known member
Dennis,
95% transmission of the HT's is the peak transmission around 555 nm, the optimum sensitivity of the eye at daylight. It is interesting to know the HT's transmission at 480-510 nm, the optimum sensitivity range of the eye at dusk and how the competitors like the new 56 mm Swarovski SLC's will perform. According to the Swarovski flyers the SLC's have a transmission of 93% and I assume that this is also at 555 nm. If that is correct, and I have no reason to think otherwise, we will not be able to see much difference in brightness between the HT's and the SLC's, since the eye can not see transmission differences of about 3% or less.
Gijs
95% transmission of the HT's is the peak transmission around 555 nm, the optimum sensitivity of the eye at daylight. It is interesting to know the HT's transmission at 480-510 nm, the optimum sensitivity range of the eye at dusk and how the competitors like the new 56 mm Swarovski SLC's will perform. According to the Swarovski flyers the SLC's have a transmission of 93% and I assume that this is also at 555 nm. If that is correct, and I have no reason to think otherwise, we will not be able to see much difference in brightness between the HT's and the SLC's, since the eye can not see transmission differences of about 3% or less.
Gijs
Gijs
On the current Swaro website they do not mention a transmission figure at all, only a vague statement about exceptional brightness. Maybe they are having some difficulty at first in maintaining 93% minimum. It only takes a few units coming through at 92.98 for the legal guys to get worried.
One bins designer mentioned to me that most people can detect a 2% brightness difference but I am not sure of the conditions of that test.
Zeiss are confident enough now to state a transmission of 95% minimum for HT.
Lee
kestrel1
Well-known member
I think that main goal of these HTx54 is to provide excellent low light binocular with best weight and not to bring the brightest ever.
I do not think that even 2% of transmission can compensate 2mm of lens diameter which has SLC, instead of fact that for low light performance is affected also by flatness of transmission curve and high values on short wavelenght. Another thing which affect low light performance in IMHO is contrast, sharpness, and except that the bigger sweetspot is affecting possibility to distinguish objects in low light.
But it is possible that binocular with smaller exit pupil can provide better low light performance, because from my comparison observation with EL SV 8,5x42 and Nikon M7 8x42 which has equal transmission acc. to Allbinos tests, I allways seen better details in EL SV.
I also wondering why manufacturers do not count mean of transmission, and means for half spectrums, and in best cases allways operate with peak transmission, d/n transmission and do not provide buyers with curve specific for binocular.
The most serious will be if each piece of binoculars on market will have its own measurement protocol acc. to its serial no. supplied in box with it, which measured by independent third party. I think that many buyers will be very pleased, that their binocular has its qualities assured, but on other hand I think that many buyers do not care and do not want detailed specs
Looking forward, and hope that soon someone will
test these "kings of twilight", and their comparison to Nobilem.
Best regards
I do not think that even 2% of transmission can compensate 2mm of lens diameter which has SLC, instead of fact that for low light performance is affected also by flatness of transmission curve and high values on short wavelenght. Another thing which affect low light performance in IMHO is contrast, sharpness, and except that the bigger sweetspot is affecting possibility to distinguish objects in low light.
But it is possible that binocular with smaller exit pupil can provide better low light performance, because from my comparison observation with EL SV 8,5x42 and Nikon M7 8x42 which has equal transmission acc. to Allbinos tests, I allways seen better details in EL SV.
I also wondering why manufacturers do not count mean of transmission, and means for half spectrums, and in best cases allways operate with peak transmission, d/n transmission and do not provide buyers with curve specific for binocular.
The most serious will be if each piece of binoculars on market will have its own measurement protocol acc. to its serial no. supplied in box with it, which measured by independent third party. I think that many buyers will be very pleased, that their binocular has its qualities assured, but on other hand I think that many buyers do not care and do not want detailed specs
Looking forward, and hope that soon someone will
test these "kings of twilight", and their comparison to Nobilem.
Best regards
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jan van daalen
Well-known member
Personally I think these two bins are the best men can buy at this moment for dusk and dawn use.
It will all depend on what scope is used on the rifle. Probably all Zeiss Victory scope users will buy the HT and the Swaro Z6i users will buy the SLC. Same goes for the leica Magnus. In that event the only model leica presents is the Geovid 56, but that one is way below the Zeiss/Swarovski performance.
Jan
It will all depend on what scope is used on the rifle. Probably all Zeiss Victory scope users will buy the HT and the Swaro Z6i users will buy the SLC. Same goes for the leica Magnus. In that event the only model leica presents is the Geovid 56, but that one is way below the Zeiss/Swarovski performance.
Jan
jan van daalen
Well-known member
But if a hunter can make sure of his target by investing in top optics it's a legitimate choice. If he chooses otherwise it's also legitimate.
I do think the Duralyt user will buy the Conquest HD 56 and will stop 15 minutes earlier or start later. Nothing wrong with that.
Same goes for nature observation. Do I need the performance level the bin in question can offer? Freedom of choice.
Why should we otherwise even bother to develop better optics.
Jan
There is a much greater risk factor in hunting than there is in birding. Common sense should prevail in this case over technology. You can trip over something in the twilight and your binoculars will not have much potential to injure you or someone else when you are birding but that does not apply when you are also carrying a firearm.
Bob
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jan van daalen
Well-known member
Bob,
This is only the case during stalking.
Down here dusk and dawn hunting is always done from solitair high positions with no movements at all. Stalking is much more done in Scandinavia and Scotland.
The main reason why Dutch hunters invest in top optics is in the fact that they often hunt in other countries and the difference between (for example) a free shot for everything (red wild) lower that the ears and a no shot for higher than the ears is a financial penalty in the last case.
Jan
David in NC
Well-known member
Huh? Can you expound on this? I have no idea what you mean.
jan van daalen
Well-known member
Down here you can roughly devide the hunting scene in two categories.
Farmers/landowners who know excactly what lives on their land. They don't have a time table. If it's not today it will be tomorrow. These guys often use the cheaper optics because for them the demands are not so high. They just quit half an hour earlier like Bob said earlier.
The other group hunts elsewhere in Europe or as a guest and pay serious money for it.
They are being told which animal may be shot and which does not. So there is a saying that every deer with horns (wrong word but you got what I mean) lower than the ears are allowed. If you shoot a deer with horns longer than the ears it's not allowed and you pay a severe penalty which is much more than the cost of a HT.
Since there is also a tendency to shoot from greater distances, the demand for better optics goes with that. Holland is flat as a pancake, but all the countries around us have hills/mountains. For us it's difficult to estimate the distance in curved territory, so rangefinders in scopes and bins come in handy.
Jan
Gijs van Ginkel
Well-known member
Dear all,
In between difficult administration tasks, I did some simple calculations to enlighten my mind and I invite you to think with me.
Suppose we have a light current with a stream of 1000 photons per square mm.
A binocular with 54 mm objective diameter has a surface of:
3,1415x27x27= 2290,153 sqmm. And it collects from the mentioned photon current 2290153 photons.
If that binocular has a light transmission of 95% it will transmit 0,95x2290153= 2175645 photons, which are leaving the eyepiece (1).
The second binocular has 56 mm objective diameter which yields a surface of 3,1415x28x28=2462,936 sqmm and it collects from the mentioned photon current 2462936 photons.
If that 56 mm binocular has a light transmission of 92%, it will transmit 0,92x2462936=2265901 photons (2), which will leave the eyepiece.
If the binocular has a light transmission of 93% the numbers are:
0,93x2462936= 2290530 photons
If this calculation is correct it means that approx.4-5% more light is entering the eye with a binocular with objective diameter of 56 mm and 92%-93% light transmission compared with a binocular with 54 mm objective diameter and 95% light transmission.
One would then expect that the 56 mm binocular has a brighter image than the 54 mm binocular.
I wish you pleasant calculations.
Gijs
.
In between difficult administration tasks, I did some simple calculations to enlighten my mind and I invite you to think with me.
Suppose we have a light current with a stream of 1000 photons per square mm.
A binocular with 54 mm objective diameter has a surface of:
3,1415x27x27= 2290,153 sqmm. And it collects from the mentioned photon current 2290153 photons.
If that binocular has a light transmission of 95% it will transmit 0,95x2290153= 2175645 photons, which are leaving the eyepiece (1).
The second binocular has 56 mm objective diameter which yields a surface of 3,1415x28x28=2462,936 sqmm and it collects from the mentioned photon current 2462936 photons.
If that 56 mm binocular has a light transmission of 92%, it will transmit 0,92x2462936=2265901 photons (2), which will leave the eyepiece.
If the binocular has a light transmission of 93% the numbers are:
0,93x2462936= 2290530 photons
If this calculation is correct it means that approx.4-5% more light is entering the eye with a binocular with objective diameter of 56 mm and 92%-93% light transmission compared with a binocular with 54 mm objective diameter and 95% light transmission.
One would then expect that the 56 mm binocular has a brighter image than the 54 mm binocular.
I wish you pleasant calculations.
Gijs
.
Holger Merlitz
Well-known member
Yes - as long as the eye pupils are wide enough to cover the exit pupils. With 8x56 and 8x54, this may rarely be the case, and to many observers that would never happen. To those, the 54mm binocular with higher transmission would (in principle) appear a bit brighter.
Cheers,
Holger
Sagittarius
Well-known member
It should be no mystery to any of us that the main reason Zeiss went with a 54mm objective is the weight factor which is significantly less than a 56mm would be.
Doubt anyone has eyesight good enough to tell the difference between the two.
I happen to believe Zeiss going with a 54mm HT is a stroke of genius. :clap:
Doubt anyone has eyesight good enough to tell the difference between the two.
I happen to believe Zeiss going with a 54mm HT is a stroke of genius. :clap:
Gijs van Ginkel
Well-known member
Dear all and also a reaction on Holgers post,
I still are hampered by difficult administrations tasks, so I take some time to go further with my calculations presented in post 16.
I supposed a photon current of 1000 photons per sqmm and the 54 mm binocular having 95% transmission then would transmit 2175645 photons. The exit pupil of an 8x54 mm is (54:8)= 6,75 mm. The surface area is 3,1415x6,75x6,75= 143,1 sqmm.
Per sqmm of exit pupil we then get a photon curent of (2175645:143,1) = 1520 photons per sqmm.
The same exercise now for the 56 mm binocular with 93% light transmission. In post 16 I had calculated that this binocular transmits 2290530 photons. These photons are concentrated in an (56:8)= 7 mm exit pupil. Its surface area is 3,1415x7x7= 153,9 sqmm.
That means a photon current of 2290530:153,9= 1488 photons per sq mm.
Compare now the photon current of the 54 mm binocular =1520 photons per sqmm
with the 56 mm binocular = 1488 photons per sqmm. A difference of around 2% ideally uniform distributed over the exit pupil.
My hypothesis is that on the basis of these data we can not observe a brightness difference between the 54 and the 56 mm binocular, since the eye is not able to see 2% differences in brightness.
To make things more complicated: brightness is not a measurable quantity (see my english review paper on the web-site of House of Outdoor entitled COLR VISION, BRIGHTNESS, RESOLUTION AND CONTRAST IN BINOCULAR IMAGES) since our eyes oberve for example yellow as a very bright color and violet is not.
So in order to observe differences in brightness between the 54 and the 56 mm binocular I have described here, the shape of the transmission spectrum is very important to observe visual differences in brightness.
On the basis of the numerical calculations there should be no observable differences.
Gijs
I still are hampered by difficult administrations tasks, so I take some time to go further with my calculations presented in post 16.
I supposed a photon current of 1000 photons per sqmm and the 54 mm binocular having 95% transmission then would transmit 2175645 photons. The exit pupil of an 8x54 mm is (54:8)= 6,75 mm. The surface area is 3,1415x6,75x6,75= 143,1 sqmm.
Per sqmm of exit pupil we then get a photon curent of (2175645:143,1) = 1520 photons per sqmm.
The same exercise now for the 56 mm binocular with 93% light transmission. In post 16 I had calculated that this binocular transmits 2290530 photons. These photons are concentrated in an (56:8)= 7 mm exit pupil. Its surface area is 3,1415x7x7= 153,9 sqmm.
That means a photon current of 2290530:153,9= 1488 photons per sq mm.
Compare now the photon current of the 54 mm binocular =1520 photons per sqmm
with the 56 mm binocular = 1488 photons per sqmm. A difference of around 2% ideally uniform distributed over the exit pupil.
My hypothesis is that on the basis of these data we can not observe a brightness difference between the 54 and the 56 mm binocular, since the eye is not able to see 2% differences in brightness.
To make things more complicated: brightness is not a measurable quantity (see my english review paper on the web-site of House of Outdoor entitled COLR VISION, BRIGHTNESS, RESOLUTION AND CONTRAST IN BINOCULAR IMAGES) since our eyes oberve for example yellow as a very bright color and violet is not.
So in order to observe differences in brightness between the 54 and the 56 mm binocular I have described here, the shape of the transmission spectrum is very important to observe visual differences in brightness.
On the basis of the numerical calculations there should be no observable differences.
Gijs
Gijs is absolutely right!
I will add,
understand the 2-3-4 percent differences in brightness is impossible, so you need to pay attention to the field of view of the optical design lens and eyepiece of the binoculars.
Even a excess only a single diaphragm in the optical design can spoil everything.
Compare photo lens diaphragm 0,8-1,2 and you will see a very interesting relation.
I will add,
understand the 2-3-4 percent differences in brightness is impossible, so you need to pay attention to the field of view of the optical design lens and eyepiece of the binoculars.
Even a excess only a single diaphragm in the optical design can spoil everything.
Compare photo lens diaphragm 0,8-1,2 and you will see a very interesting relation.
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