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Meopta 8x32 First impressions (1 Viewer)

Frank,
I do not have the information form the Meopta site but from the booklet published by Meopta about the Meostars and other products. Moreover nothing of that kind of information is given on the binocular itself, so what how can we be sure that the coatings are applied?
Gijs
 
Gijs van Ginkel said:
Frank,
I do not have the information form the Meopta site but from the booklet published by Meopta about the Meostars and other products. Moreover nothing of that kind of information is given on the binocular itself, so what how can we be sure that the coatings are applied?
Gijs
Click to expand...

Gijs:

You have a good point that you have made here. It seems Meopta is not
forthcoming with details of binocular construction, but rather secretive, and
in this day and age that is not a good thing.

I like your reviews, and it must be difficult when you don't have details to
show about coatings, etc.

So, I hope Meopta is watching.

Jerry
 
Gijs,

One could use the rather simple polarizing test with a computer screen, no? That would help to identify whether or not they are phase coated. That would provide physical evidence for or against it.

On the other hand, with a fairly large amount of experience with all of the original Meostar lineup and some additional experience with non-phase coated roofs my eyes tell me they are phase coated.

http://swfa.com/Meopta-7x42-Meostar-Binocular-P7969.aspx

That was the only site I found where it mentioned phase coating and it isn't Meopta's site.

The suggestion of a silver prism coating was based on circumstantial evidence...published light transmission curves(versus competitors of similar quality) plus, again, my experience with silver coated prism roofs and the warm bias that my eyes relate as I look through them.
 
plyscope said:
The Binomania review (of the 8x32) has a cutaway of a 42mm that describes phase correct prisms.

http://www.binomania.it/binocoli/meopta8x32/meopta8x32.php

Allbinos review states they are phase correction coated.

http://www.allbinos.com/185-binoculars_review-Meopta_Meostar_B1_8x32.html

Holgers review states they have a silver coated mirror.

http://www.holgermerlitz.de/meopta8x32.html
Click to expand...

When Miss Lulubelle called Meopta, the rep also said that the Meostars have silver coated prisms. So I think that's a done deal, but what's less certain is if the HD version has dielectric coatings. The rep told her the HD also had silver coatings.

No mention of coating type at EO:

http://www.eagleoptics.com/binoculars/meopta/meopta-meostar-10x42-hd-binocular

I'm overstocked.com on 10x, but I hope they make a 7x42 HD, because at 7x, the image would likely be CA free like the 7x36 ED2.

<B>
 
Dear all,
I know that one can see quickly with polarizing filters whether phase correction coatings are applied and one can also check the quality of it.
My point was that Meopta makes a beautiful very well illustrated information book about all technical details of the new and older products and with a certain pride the multi coating is mentioned, but no trace of phase correction coatings or a high reflective mirror.
If a silver mirror is applied han that is not a good prospect for the future, listening to the optical designer and quality manager of Bleeker optics: silver mrros age and with ageing light transmission dereases and grdaul yellowing of the image takes place.
The light transmission spectra on all Meopta binoculars we have measured show a color bias in the yellow-red spectal region and transmission values are quite a bit lower than in other brands also in the same price region.
Gijs
 
Gijs van Ginkel said:
Dear all,
I have studied the information Meopta supplies with regard to the technical properties of their Meostar binoculars. Mentioned is Meobright MB5501 the new multicoating Meopta applies "auf die Linsen und Prismen "(qoute). No mention is made of a phase correction coating or a high reflective mirror on the Schmidt-Pechan roof prism. So no silver mirror, no aluminium mirror and no di-electric mirror. That can explain why we found low light transmission in all Meopta binoculars we measured (I think the transmission spectrum in post 8 over estimates the transmission of the 8x32, since we never measured a similar spectrum). Up to now we have investigated the 8x42 Meostar, the 6,5x32 and the 8x32. All have light transmissions of either below 80% or just above it. That would be in agreement with the lack of a high reflective mirror on the Schmidt-Pechan prisms.
Meopta mentions the presence of HD-glass in the Meostars by which they mean ED glass if we look at the picture supplied with it.
The description of the binoculars do not mention the presence of protective lenscoatings, which applied on the telescopic Meopta gunsights.
If we can trust the Meopta information we are stuck with an 800 euro 8x32 without phase correction coating, without an high reflective mirror on the roof prisms to avoid light losses and without a water and dust repellent coating and a not optimal light transmission in that price region.
John, post 17, if we look at the sensitivity of the three different cone types then light transmitted at 800 nm is not of importance for our vision with binoculars.
Gijs
Click to expand...

Dear Gijs,

Is it possible for you to attach the transmission curve you have measured for the Meostar 8x32? The one shown in posting #7 (I guess it is from Allbinos) indicates something far beyond 80%, when folded with the human (daylight) sensitivity curve. So let's see if the both measurements deliver similar (but scaled) or otherwise distorted curves.

Cheers,
Holger
 
Gijs,

I certainly would agree that dielectric coatings on the Meostar is needed to make them competitive on all levels with the more expensive competition. My curiosity is piqued as to why Meopta has not upgraded this feature especially after choosing to upgrade to ED glass in the objective design. Dielectric coatings trickled down into lower price ranges before ED glass did at least in my experience.

There must be an explanation for this with the Meopta. Thoughts? Anyone?
 
Gijs,

I did not suggest that transmission at 800 nm is of any visual importance. I KNOW we can't see it. However, most bins with Porro or Abbe-König prisms still have significant transmission at this frequency, as do those with a metallic mirror coating on the Schmidt-Pechan prisms. Conversely around 50% transmission at this frequency of a bin with Schmidt-Pechan prisms is an indication of metallic coating.

BTW, silver loses its reflectivity by reacting with hydrogen sulfide in the atmosphere to form silver sulfide. It does not react with nitrogen in a sealed bin.

I have just checked my wife's 7x42 Meostar against a TFT screen with a polarizing filter. It has excellent phase coatings.

In the 2010 Vögel/Interstellarum test of 10x42 bins the Meostar (non-HD version) had day and night transmission values of 87% and 81% respectively. These values were measured according to ISO in Leica's laboratories.

John
 
Last edited:
John,
I got your point with regard to 800 nm transmission: we agree. With regard to checking the presence of phase correction coatings: I may not understand you here,therefore my question: how exactly did you check the presence of this coating? I ask this since Weyrauch and Dörband (Deutsche Optikerzeitung 1988) gave a precise description how to check this and you need two crossed linear polarizers for a correct control.
Our transmission values on the 8x42 Meostar were lower than the values you refer to for the 10x42. We have performed control experiments on instruments, which were also measured by an international institute for optical calibration standards. Our measured values were within expermental error identical except for one value at 450 nm.
That does not mean that we never make errors. Therefore we check the data as well as we can by performing the necessary control experiments.
The ageing of silver mirrors affects in the end the optical performance of the binocular, no matter what kind of chemical reaction occurs. The binoculars are filled with dry nitrogen gas, but that does not mean that they stay impermeable for years to oxygen leaking in.
Hydrogen sulphide gass (H2S) is very poisonous and I do not see how this can be formed inside a nitrogen-purged binocular or how it can leak into the binocular from the outside, since you can only hope that the concentration in the air around us is extremely low.

Holger,
I hope to supply you with the spectrum of the 8x32 in the coming week, since I have to collect it from the lab. (and the children had school vacantions this week, which kept me fairly busy with other things than binoculars), so I did not have all my data at home.
Gijs
 
Gijs van Ginkel said:
John,
I got your point with regard to 800 nm transmission: we agree. With regard to checking the presence of phase correction coatings: I may not understand you here,therefore my question: how exactly did you check the presence of this coating? I ask this since Weyrauch and Dörband (Deutsche Optikerzeitung 1988) gave a precise description how to check this and you need two crossed linear polarizers for a correct control.
Our transmission values on the 8x42 Meostar were lower than the values you refer to for the 10x42. We have performed control experiments on instruments, which were also measured by an international institute for optical calibration standards. Our measured values were within expermental error identical except for one value at 450 nm.
That does not mean that we never make errors. Therefore we check the data as well as we can by performing the necessary control experiments.
The ageing of silver mirrors affects in the end the optical performance of the binocular, no matter what kind of chemical reaction occurs. The binoculars are filled with dry nitrogen gas, but that does not mean that they stay impermeable for years to oxygen leaking in.
Hydrogen sulphide gass (H2S) is very poisonous and I do not see how this can be formed inside a nitrogen-purged binocular or how it can leak into the binocular from the outside, since you can only hope that the concentration in the air around us is extremely low.

Holger,
I hope to supply you with the spectrum of the 8x32 in the coming week, since I have to collect it from the lab. (and the children had school vacantions this week, which kept me fairly busy with other things than binoculars), so I did not have all my data at home.
Gijs
Click to expand...

Sure GIjs, family comes first, let us analyze the transmission curves some time next week! The aging of silver layers should not be an issue any more - I read about protective layers coating the mirrors and sealing them effectively. Sure that doesn't mean Meopta is applying them, at least they could if they wanted to.

Meopta could (just as most of the other mid-range binocular producers do) purchase their prisms, readily coated with P-coating and dielectric mirror, from any one of the big glass factories such as Hoya or Ohara or Schott. There are all kinds of quality levels, they could choose whatever they regard suitable. Perhaps they can't because their prism dimensions are somewhat unusual, so that they are stuck with in-house facilities and those are lacking high-end dielectric coating technology? Hard to tell, but they must have a reason. From my side, I actually like the warm tone of the image through the Meopta, it makes the observation in sunlight very relaxing and seems to improve the contrast over large distances (due to suppression of light from atmospheric scattering). I regard metallic mirrors more eye-friendly than those cold dielectric mirrors ;-)

Cheers,
Holger
 
Last edited:
Sweet. Another bin user who often prefers the golden hue often associated with silver coated prisms. I am glad to see it explained so eloquently.
 
Even with silver coated prisms, the image could be made nearly perfectly colour neutral.
It's all up to the choice of glass and coatings in the whole binocular, rather than only what type of prism coating that is used.

The use of dielectric coating, just like the lens coatings, can be tweaked in many ways but in the end, only the delivered results count.
I'm quite sure, though, that dielectric coatings allow a greater allround transmission.
If a silver coating is applied, the tweaking of the lens coatings (in order to obtain a neutral bias) may result in a lesser overall transmission rate.

Thus, the silver coating may present an obstacle if both high transmission and natural colours is the objective.
 
Gijs van Ginkel said:
John,
I got your point with regard to 800 nm transmission: we agree. With regard to checking the presence of phase correction coatings: I may not understand you here,therefore my question: how exactly did you check the presence of this coating?
Gijs
Click to expand...

Gijs,

I thought the whole question of mirror and phase coatings worthy of a separate discussion and have started a new thread.

John
 
For clarification, Meopta offeres only one model of binocular with HD optics and that is the MeoStar B1 10x42 HD. It has two fluorite lenses in the objective which help eliminate secondary color aberration.
ALL Meopta MeoStar B1 binoculars have phase-coated Schmidt-Pechan roof prism systems.
 
MeoptaMan,

I've only been able to try the Meopta Meostar range on a couple of occasions in far from ideal conditions. Like Frank and Holger I can find a warm bias pleasing, but I thought I noticed differences between models and between the two occasions I tried them. As I recall the 7x42 and the x50s seemed warmer than the x32s and the other x42. On the last occasion the 8x32 and the 10x42 HD seemed closer still to neutral. Did I imagine it or are there different prism and/or lens coating applied to different models or some incremental improvements over the last couple of years?

The 10x42 HD really impressed by the way. I hope the formula finds it's way into the x32s in particular.

David
 
Last edited:
MeoptaMan said:
For clarification, Meopta offeres only one model of binocular with HD optics and that is the MeoStar B1 10x42 HD. It has two fluorite lenses in the objective which help eliminate secondary color aberration.
ALL Meopta MeoStar B1 binoculars have phase-coated Schmidt-Pechan roof prism systems.
Click to expand...

Meoptaman:

You have read all of the posts wondering about the prism coatings of the
Meostar, and I also would like to know about the Meopro.

Tell us what the prism coatings are, alum. silver, di-electric?

Communication is important.

Jerry
 
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
 
Gijs,
Thanks for another round of transmission measurements!

Regarding the Fujinon 10x50. I am one who has believed the 95% value, not only from Fujinon's advertisements, but also from the high values appearing in the Allbinos review site. The FMTs also strike my eyes as being rather bright, but I guess they aren't worth much vs a sophisticated research device!

As for your measurement of the Meostar as compared with Allbinos's (shown by Brock), yours is flatter than theirs, as it was for your recent curve for the Zeiss FL. So that looks like a pretty consistent difference. Lately it seems like most of their plots drop steadily and steeply towards the blue, and I have thought that seemed strange.

If you aren't familiar with the Allbinos reviews, I think you would find it interesting to look at their measurements (transmission plots are given for about half the recent reviews) and see what you think.
Ron
 
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