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Meopta 8x32 First impressions (1 Viewer)

Ron,
A light transmission of 85-90% in the wavelenth region 550-650 nm with an exit pupil of 5 mm can yield a nice and bright view and the Fujinon certainly has that view, but it could perhaps even perform better still with a higher light transmission. And we can not exclude that there can be a quality variation between different Fujinons, since we measured only one binocular.
Gijs
 
Gijs,

What is the maximum binocular transmission you have measured?
Do you have a list of different binocular transmissions?

Do you take into account vignetting and actual clear objective aperture rather than claimed aperture?
Occasionally I have measured front clear apertures larger than marked but have not measured light throughput.
Have you measured uncoated 7 x 50 or 10 x 50 binocular transmission?
Do you find a reduction of transmission with age in uncoated binoculars or an increase due to natural blooming?
Does the real or marked magnification make a difference?

If you don't have these details that is o.k. I just was interested if you have taken such measurements.
 
Gijs van Ginkel said:
Perhaps it is nice to compare the properties of the Kite Petrel 8x32 which is sold for 426 euro in Europe with the Meopta Meostar 8x32, sold for 785 euro.
-1- Kite Petrel 8x32: Schmidt-Pechan roof prisms with phase correction coatings and di-electric high reflection mirror. Weight 547 g, FOV 131 m/1000 m, close focus 1,3 m, revolutions from CF to infinity 1,25, transmission at 500 nm: 82% and at 550 nm: 85,5%.
Eye relief 17 mm. Excellent after sales service.
-2- Meopta 8x32: Schmidt-Pechan roof prisms with phase correction coating and high reflective silver mirror. Weight 608 g, FOV 139m/1000m, close focus 1,6 m, revolutions from close focus to infinity 1,75, transmission at 500 nm: 84,8% and at 550 nm: 87,6%, eye relief 15,5 mm, after sales service bad.
Gijs
Click to expand...

For pure optical properties, better to choose the 8x30 Habicht at 730 euros than the Meopta 8x32. Its WP and Swaro after sales service is normally very good. No bad surprises.
I did not like the Meoptas image colour a bit too yellowish. I never tried the Kite.
If you really want a 8x32 roof, the 740€ Conquest HD could be a better choice than the Meopta imo. The Conquest HDs are very very good :t:
 
Gijs van Ginkel said:
Holger (post 28),
We have measured and remeasured the transmission spectrum of the Meopta Meostar 8x32 and it does not match the spectrum from post 7.
I write down our values and between brackets the values of the spectrum shown in post 7:
460 nm: 77,2% (81,5%)
500 nm: 84,8% (87%)
550 nm: 87,6% (90,4%)
600 nm: 89,3% (94%)
650 nm: 88,3% (93%)
670 nm: 84,8% (92%)

For your information: we also measured and remeasured the light transmission of the Fujinon 10x50 FMTR-SX and it never reached a light transmission of 95% (a value which is often mentioned on this forum, but I do not know the origin of this (mis)information). At 550 nm the Fujinon has a light transmission of 85,2% and its maximum transmission before going down again is around 650 nm where it has a light transmission of around 89%.

The Meopta 8x32 costs in Holland 785 euro and the after sales service is has the same level of the Nikon after sales service: very bad.

Perhaps it is nice to compare the properties of the Kite Petrel 8x32 which is sold for 426 euro in Europe with the Meopta Meostar 8x32, sold for 785 euro.
-1- Kite Petrel 8x32: Schmidt-Pechan roof prisms with phase correction coatings and di-electric high reflection mirror. Weight 547 g, FOV 131 m/1000 m, close focus 1,3 m, revolutions from CF to infinity 1,25, transmission at 500 nm: 82% and at 550 nm: 85,5%.
Eye relief 17 mm. Excellent after sales service.
-2- Meopta 8x32: Schmidt-Pechan roof prisms with phase correction coating and high reflective silver mirror. Weight 608 g, FOV 139m/1000m, close focus 1,6 m, revolutions from close focus to infinity 1,75, transmission at 500 nm: 84,8% and at 550 nm: 87,6%, eye relief 15,5 mm, after sales service bad.
Gijs
Click to expand...

Gijs:

Thanks for your reviews, I have read your full 2010 42 mm review, and have it as a
reference. You answered my question from above about the
Meopta, and its prism coatings.

I asked Meoptaman, but no response, and that shows a lack of whatever.
I have been in sales for many years, this guy would have been shown the
door if he was on my sales team.

Jerry
 
Gijs van Ginkel said:
Holger (post 28),
We have measured and remeasured the transmission spectrum of the Meopta Meostar 8x32 and it does not match the spectrum from post 7.
I write down our values and between brackets the values of the spectrum shown in post 7:
460 nm: 77,2% (81,5%)
500 nm: 84,8% (87%)
550 nm: 87,6% (90,4%)
600 nm: 89,3% (94%)
650 nm: 88,3% (93%)
670 nm: 84,8% (92%)

For your information: we also measured and remeasured the light transmission of the Fujinon 10x50 FMTR-SX and it never reached a light transmission of 95% (a value which is often mentioned on this forum, but I do not know the origin of this (mis)information). At 550 nm the Fujinon has a light transmission of 85,2% and its maximum transmission before going down again is around 650 nm where it has a light transmission of around 89%.

The Meopta 8x32 costs in Holland 785 euro and the after sales service is has the same level of the Nikon after sales service: very bad.

Perhaps it is nice to compare the properties of the Kite Petrel 8x32 which is sold for 426 euro in Europe with the Meopta Meostar 8x32, sold for 785 euro.
-1- Kite Petrel 8x32: Schmidt-Pechan roof prisms with phase correction coatings and di-electric high reflection mirror. Weight 547 g, FOV 131 m/1000 m, close focus 1,3 m, revolutions from CF to infinity 1,25, transmission at 500 nm: 82% and at 550 nm: 85,5%.
Eye relief 17 mm. Excellent after sales service.
-2- Meopta 8x32: Schmidt-Pechan roof prisms with phase correction coating and high reflective silver mirror. Weight 608 g, FOV 139m/1000m, close focus 1,6 m, revolutions from close focus to infinity 1,75, transmission at 500 nm: 84,8% and at 550 nm: 87,6%, eye relief 15,5 mm, after sales service bad.
Gijs
Click to expand...

Thanks again Gijs - so we definitely have different results, and these differences are larger than the expected error during the measurement. I have no clue how this is possible - in red, the measurements differ by more than 7%. Perhaps your light source is cooler than the one used by Arek.


It is obvious that some of Arek's measurements delivered too high values (98% is not possible with any existing binocular).

How exactly do you calculate the overall transmission - is it weighted with the human eye spectral sensitivity curve or is it an unweighted average inside a certain interval (400nm to 700nm for example)?

Cheers,
Holger
 
Is the transmission percentage measured using the whole exit pupil or just the centre of the exit pupil?
I wouldn't think the illumination is uniform across the whole exit pupil.
Perhaps different labs are measuring different things.

The Eschenbach 3 x 22? Tele-Med could I think reach 98% transmission if it was multicoated.
I think mine is single coated and maybe 95%.
 
Dear all,
That is a lot of questions, but I will try to answer them as well as possible.
Binastro (post 42);
- The maximum transmission we ever found was in the Swarovsi Habicht 8x30 porro and it was 95,5%-96%.
- Yes I have long lists of measured spectra of binoculars made in the time period 1850 until now and no (on the question you may ask) I do not intend to publish this whole list, since it is simply to much work and there is more to life than binoculars
- Do we take into account vignetting and objective size. Yes, as a light source we have a stabilised tungsten lamp, which is extremely stable over time and we select the centre of the image for the measurements. The data obtained correlate within experimental error measurements done on the whole image (we checked it).
- Yes we have measured uncoated 7x50 and 10x50 if I remember well, but that does not make any difference compared to uncoated other type noculars, since only the optical pathlenght and the number of glass components determine the amount of light transmitted.As an example: the uncoated Leitz army binocular 08 from WW-1 (made in 1917) has a very low number of lenses and no prisms (it has the construction of a so-called theatre glass or Holland glass, but some also call it a Gallilei glass, allthough he never invented a telescope or binoculars (as he wrote himself), that was done by a Dutch spectracle maker in 1608). And that Leitz army 08 binocular had a light transmission of 70% at 555 nm.
- Did we see changes in transmission with ageing glass? We did not investigate that allthough here are historic reports that whithering of glass surfaces if not to bad may increase transmission as a result of the anti-refection effects of this aged surface layer.
- Magnification does not have any effect on light transmission, that is fully determined by optical pathlenght, light absorption by the glass components used and the quality of the coatings.
Holger (post 45):
We measure absolute values of transmission and we do not look at the spectral sensitivity of the eye, since that is hidden under the transmission curve.
What I have done a couple of times is: measuring the total transmission in the wavelenght range at which the eye is sensitive. We did that by using a detector with the same spectral response curve as the eye. The binocular or telescope is aimed in that occasion at a perfectly white illuminated surface (stabilised light source, so there are no detectable intensity fluctuations). However, we decided that measuring the total transmission over a certain spectral range is accurate enough to correlate it with our visual observations.
Binastro (post 46):
Effects of non uniform transmission over the image is ruled out by our measuring protocol.
Gijs
 
Digges telescope invented 1583?
I actually think simple telescopes may have been known much earlier.

Francis Bacon invents frozen chicken 1593? I doubt that as probably known in Russia much earlier. I have heard of birds falling frozen from the sky at minus 40.

I have a 7 x 50 Leitz porro uncoated which gives wonderful images and not many ghosts.
I guess transmission is 55% with 3 element eyepiece, but has anyone measured its transmission?
 
Gijs van Ginkel said:
Dear all,
That is a lot of questions, but I will try to answer them as well as possible.
Binastro (post 42);
- The maximum transmission we ever found was in the Swarovsi Habicht 8x30 porro and it was 95,5%-96%.
- Yes I have long lists of measured spectra of binoculars made in the time period 1850 until now and no (on the question you may ask) I do not intend to publish this whole list, since it is simply to much work and there is more to life than binoculars
- Do we take into account vignetting and objective size. Yes, as a light source we have a stabilised tungsten lamp, which is extremely stable over time and we select the centre of the image for the measurements. The data obtained correlate within experimental error measurements done on the whole image (we checked it).
- Yes we have measured uncoated 7x50 and 10x50 if I remember well, but that does not make any difference compared to uncoated other type noculars, since only the optical pathlenght and the number of glass components determine the amount of light transmitted.As an example: the uncoated Leitz army binocular 08 from WW-1 (made in 1917) has a very low number of lenses and no prisms (it has the construction of a so-called theatre glass or Holland glass, but some also call it a Gallilei glass, allthough he never invented a telescope or binoculars (as he wrote himself), that was done by a Dutch spectracle maker in 1608). And that Leitz army 08 binocular had a light transmission of 70% at 555 nm.
- Did we see changes in transmission with ageing glass? We did not investigate that allthough here are historic reports that whithering of glass surfaces if not to bad may increase transmission as a result of the anti-refection effects of this aged surface layer.
- Magnification does not have any effect on light transmission, that is fully determined by optical pathlenght, light absorption by the glass components used and the quality of the coatings.
Holger (post 45):
We measure absolute values of transmission and we do not look at the spectral sensitivity of the eye, since that is hidden under the transmission curve.
What I have done a couple of times is: measuring the total transmission in the wavelenght range at which the eye is sensitive. We did that by using a detector with the same spectral response curve as the eye. The binocular or telescope is aimed in that occasion at a perfectly white illuminated surface (stabilised light source, so there are no detectable intensity fluctuations). However, we decided that measuring the total transmission over a certain spectral range is accurate enough to correlate it with our visual observations.
Binastro (post 46):
Effects of non uniform transmission over the image is ruled out by our measuring protocol.
Gijs
Click to expand...


OK thanks a lot for clarification. This at least explains some of the major differences in quoted overall transmission: Usually, transmission through a binocular is highest somewhere between 500 and 600 nm, and dropping toward both sides of the spectrum. The eye's sensitivity (v-lambda-curve) strongly suppresses the regions of violet, blue and red, and when weighted with this curve, the total visual transmission is a couple of % higher compared to the unweighted curve. Usually, laboratories additionally distinguish between daytime and nighttime transmission - since there are different sensitivity curves for photopic and scotopic vision. For example, the Zeiss FL is known to have a particularly high transmission for scotopic vision (good for hunters in the night).

http://en.wikipedia.org/wiki/Luminosity_function

Cheers,
Holger
 
Gijs van Ginkel said:
Dear all,
That is a lot of questions, but I will try to answer them as well as possible.
Binastro (post 42);
- The maximum transmission we ever found was in the Swarovsi Habicht 8x30 porro and it was 95,5%-96%.
- Yes I have long lists of measured spectra of binoculars made in the time period 1850 until now and no (on the question you may ask) I do not intend to publish this whole list, since it is simply to much work and there is more to life than binoculars
- Do we take into account vignetting and objective size. Yes, as a light source we have a stabilised tungsten lamp, which is extremely stable over time and we select the centre of the image for the measurements. The data obtained correlate within experimental error measurements done on the whole image (we checked it).
- Yes we have measured uncoated 7x50 and 10x50 if I remember well, but that does not make any difference compared to uncoated other type noculars, since only the optical pathlenght and the number of glass components determine the amount of light transmitted.As an example: the uncoated Leitz army binocular 08 from WW-1 (made in 1917) has a very low number of lenses and no prisms (it has the construction of a so-called theatre glass or Holland glass, but some also call it a Gallilei glass, allthough he never invented a telescope or binoculars (as he wrote himself), that was done by a Dutch spectracle maker in 1608). And that Leitz army 08 binocular had a light transmission of 70% at 555 nm.
- Did we see changes in transmission with ageing glass? We did not investigate that allthough here are historic reports that whithering of glass surfaces if not to bad may increase transmission as a result of the anti-refection effects of this aged surface layer.
- Magnification does not have any effect on light transmission, that is fully determined by optical pathlenght, light absorption by the glass components used and the quality of the coatings.
Holger (post 45):
We measure absolute values of transmission and we do not look at the spectral sensitivity of the eye, since that is hidden under the transmission curve.
What I have done a couple of times is: measuring the total transmission in the wavelenght range at which the eye is sensitive. We did that by using a detector with the same spectral response curve as the eye. The binocular or telescope is aimed in that occasion at a perfectly white illuminated surface (stabilised light source, so there are no detectable intensity fluctuations). However, we decided that measuring the total transmission over a certain spectral range is accurate enough to correlate it with our visual observations.
Binastro (post 46):
Effects of non uniform transmission over the image is ruled out by our measuring protocol.
Gijs
Click to expand...



I have asked this question before and perhaps it has been answered and I missed it but can anyone give a reason, or reasons, why these Swarovski 8 x 30 Habichts have light transmission measurements so much higher than other binoculars?

I understand that most people cannot discern a difference in 3% transmission but never the less there must be a reason.

I asked this question about the new Zeiss HT (a roof prism) and Holger responded that it was because of the new Schott HT glass.

http://www.birdforum.net/showpost.php?p=2668910&postcount=1214

Could it be because the Habichts are, for all practical purposes, near custom made items built near the time they are ordered using glass with the most up to date coatings? On that note I wonder if older versions of them also have similar light transmission measurements?

Bob
 
ceasar said:
I have asked this question before and perhaps it has been answered and I missed it but can anyone give a reason, or reasons, why these Swarovski 8 x 30 Habichts have light transmission measurements so much higher than other binoculars?

I understand that most people cannot discern a difference in 3% transmission but never the less there must be a reason.

I asked this question about the new Zeiss HT (a roof prism) and Holger responded that it was because of the new Schott HT glass.

http://www.birdforum.net/showpost.php?p=2668910&postcount=1214

Could it be because the Habichts are, for all practical purposes, near custom made items built near the time they are ordered using glass with the most up to date coatings? On that note I wonder if older versions of them also have similar light transmission measurements?

Bob
Click to expand...

Swarovski surely has a coating of outstanding quality, developed for the SV binoculars, so why not using a similarly good coating for the Habicht. The Habicht has less glass than the SV and hence it should have a higher transmission if coated similarly. Frankly, I do not yet quite trust in measured transmission data of 95-96%, seems too good to be true, but I may as well be wrong here, just a bit careful as usual ;-)

Cheers,
Holger
 
Holger (post 53),
I can not help a non-believer, but I trust our measurements, since we know very well what we are doing, we are aware of potential pittfalls and we checked the measurements over and over. In addition we had our spectrometer calibrated by measuring standard instruments which were also measured by a German calibration institute and we had within experimental error exactly the same results. The only deviations which we could have are in the wavelenght range 450-460 nm, but that has to do with the relatively low output of blue light of our source of white light: a stabilised tungsten light source. That problem can be tackeled by collecting enough counts in the channels of the photon counter designated to these wavelengths since the uncertainty is connected to the square root of he total amount of counts collected in these channels. Over and we found the same results as Swarovski with their spectrometer (see their data sheet in which a transmission of 96% is reported for the Habicht 8x30).
We have also compared or data from different binoculars with data obtained by Zeiss with their spectrometer and we had the same results.
Zeiss found a (green) light transmission for the HT's of 95,3%, we measured 95,1-95,2%, which is within experimental error the same.
So I am not trying to convert you from a non-believer to a believer, but scientific pride does not permit us to make stupid mistakes and we are fully independent from whatever company, what does sometimes not make us popular.
Gijs
 
Digges telescope apparently an Elizabethan military classified item.
But not a binocular.

If a cheap 10 x 50 binocular has a glass transmission of 60% because of two single coatings only front and back, but a vignetted aperture of 39 to 42 mm as actually happens,
how is the transmission recorded?
Is it 60% or about 40%?
How would a lab record this figure?

What is the lowest transmission recorded for a properly clean prismatic binocular?
 
Binastro (post 55).
If you have a binocular with an objective opening of 50 mm and you paste a diaphragm on it, so only a hole of 20 mm stays open: that does not change the transmission, since that is dependent on the optical pathlength through the glass components in combination with the quality of the coatings. Under the conditions I have sketched nothing changes with regard to optical pathlength or coating quality.
Gijs
 
Thanks Gijs,

I thought that must be the case.
So to know how bright a binocular is assuming one uses the whole aperture, one needs to know the percentage transmission and the true aperture.
That is also why I asked earlier if the true magnification matters.
If the marked aperture is 50mm and the actual front aperture less or the prisms too small or other internal vignetting then the binocular passes less light than one would think.

In addition, I think that with two persons, one having a 7mm dilated pupil and another 4mm, the 7mm person might have a smaller actual objective size if the field edges are vignetted, because the exit pupil is vignetted.

So what I am saying is transmission figures by themselves are not enough to define a binocular and don't give the whole picture.

Of course in the daytime where the eye pupil stops down the binocular, the actual aperture may not be a factor.

Many binoculars are vignetted, but hopefully not too many of the top tier.
 
From my point of view for astronomy if the 60% transmission 10 x 50 is actually only 40mm clear aperture then the instrument only transmits 38% of the light that a 100% transmission full 10 x 50 would transmit.
As a very good 10 x 50 might transmit 92% average I would say the cheap 10 x 50 only transmits about 42% as much light as the very good binocular.

I have seen such differences in actual binoculars used for astronomy.
 
Binastro,
I think that you are confusing things. Light transmission is fully dependent on the optical pathlength which light has to go through the glass components, the absorption of light by these glass components (optical glass does absorb light and this absorption is wavelength dependent) and the effect of coatings to prevent light loss due to reflections.
What you are talking about is changes in exit pupil due to changes in front lens diameter with constant magnification and that has nothing to do with the light transmission we are talking about here.
I think that you are refering to brightness of the image (image clarity may be a better term) and image clarity or brightness is dependent on a combination of two factors:
(a) the size of the exit pupil and
(b) the amount of light that the optical system transmits.
These to factors determine the image clarity. So an optical system with exit pupil of 1 mm can have exactly the same transmission as a system with 7 mm exit pupil, but higher image clarity is then brought about by the size of the exit pupil and that will give the system with 7 mm exit pupil a brighter image.
On the other hand an optical system with 4 mm exit pupil and 90% light transmission has a brighter image quality than an optical system with 7 mm exit pupil and 40% light transmission.
I hope that I am sufficiently clear to avoid misunderstanding.
Gijs
 
No Gijs,
I agree with you, I understand you and am not confusing the issue.
What I am pointing out is that the light grasp or the faintest star visible is dependent on the transmission percentage and actual aperture.
In the case of the poor vignetted and very good unvignetted 10 x 50, stars 1.0 magnitudes fainter i.e. 2.5x fainter are visible in the better instrument. This is a big difference.

I realise that no optical instrument can increase the surface brightness of an object, it can only be less bright, however slightly, unless you have an image intensifier or digital interface.
The reason one can see low surface brightness objects better with magnification is that the image is larger on the retina, say with M33.

I am merely pointing out that a 7mm exit pupil is more likely to be vignetted than a 4mm in the same instrument, which is not designed to have extra marginal illumination.

For bird watching, I also think that it is important to state whether a binocular is vignetted or not, and many are. In addition to its transmission percentage.
 
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