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New Miyauchi 7x50W Binon

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#1 holger_merlitz

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Posted 18 October 2004 - 05:01 PM

I have received the new 7x50 wide-angle binocular by Miyauchi. The following review is a comparison with the Fujinon 7x50 FMT-SX and the Tasco No. 124:

http://www.geocities...yauchi7x50.html

Have fun,
Holger

#2 KennyJ

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Posted 18 October 2004 - 06:34 PM

Holger,

As always , I thoroughly enjoyed reading this ,the latest in your now customary set of 3 -way reviews.

Your style of reviewing is unique as far as I am aware , and you never fail to bring to the reader's attention , interesting little details which no other reviewer I'm aware of tends to touch upon.

A typical example in this review is how you noticed the fact that the "below centre" optimised focussing area of the Miyauchis can actually be "useful" when targeting a typical terrestrial scene when the area occupied by sky is superfluous.

The inclusion of the 1960s Tasco model could ,in itself , be regarded as an educational bonus , particularly for younger or less well -informed readers , many of whom can be forgiven for perhaps being more accustomed to that name being more or less exclusively synonymous with "cheap rubbish".

Being quite partial to wider -angle binoculars of any magnification , I'm personally glad the new Miyauchi, with it's 9.5 degree TFOV ,is such a succesful attempt at providing an option for those so inclined as to have impressed a reviewer as scrupulous as yourself.

I was , however, quite surprised though that you did not include the Nikon Pro-star in your contenders for "best 7 x 50s available".

I'm sure everyone who takes the time to read this review will , as you put it -- " have fun".

Regards , Kenny

#3 Claudio

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Posted 19 October 2004 - 02:44 AM

Hello Holger,
I agree with Kenny on your authoritative and enjoyable binoculars corner.
About the not symmetrical sharpness performance of the Miyauchi: triplets let me think that there aren’t eccentrics for collimation, so I would guess that the axes alignment is obtained by tilting the Porro II cluster. Excessive tilting of the prism cluster could introduce the observed effect on sharpness performance.
About Porro II prisms: I have very little experience with them, and not in binoculars.
Does somebody know if their shifting can have effect on axes alignment, thus being a way to collimate the Porro II binoculars?
Cheers
Claudio

#4 holger_merlitz

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Posted 19 October 2004 - 04:16 AM

Hello Kenny,

Thanks for your encouragement! Regarding the Nikon Prostar: I haven't mentioned it because I didn't know about :-) It seems to be hardly available here in Germany. If it is as good as the Nikon SEs (and I guess it is!), then it should be a tough competitor to the Fujinon. Maybe once upon a time I will be able to check it out...

Regards,
Holger

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Posted 19 October 2004 - 07:16 AM

Excellent write-up Holger! Your review and comparison is very thorough. I would some-what disagree your reason that 7x50 binos are not common in astronomy however. I don't believe that a lack of FOV, for hand held binos, are the reason. It has more to do with exit pupil & pupil size mismatch. [Although the two parameters are intimately related.]

Aside from that, excellent job and I look forward to more.

#6 EdZ

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Posted 19 October 2004 - 11:12 AM

Excessive tilting of the prism cluster could introduce the observed effect on sharpness performance.


The above "observed affect on sharpness", that is, sharpness that appears to be off-center with the optical axis, resulting in one edge of the lens having better and the opposite edge having less sharpness, can be and probably is introduced by tilted prism pairs. While the prism pairs are tilted to obtain merged images, the optical axis can be off-center. if the axis is off-center, one edge of the view can most definitely appear less sharp. I have observed this in some large binoculars.

edz

#7 hvezdar1972

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Posted 28 April 2005 - 04:33 PM

Hi everyone,
I posted my impressions of these binos on astromart, but thought that some people interested in the Binon might look here instead, especially because there is already a link to Holger Merlitz's excellent review and pictures. So it is secondhand, sorry, but I hope still of interest to someone.
Nils
__________
I recently bought a pair of these used and spent a couple of afternoons and nights with them before returning them. This was not long enough for a full review, but because of the interest and the scarcity of user reports, I thought I would post my impressions here. I've had a pair of Fujinon Polaris 7x50s for 3 years now, they have given me some of my most enjoyable views in this hobby. For all of their great qualities, they are also well-known for being too heavy and with only a moderately wide apparent field of view. The Miyauchis are lighter and have 66 degrees afov (9.5 degrees real fov), so it was with great interest that I read the reports of Holger Merlitz and Fan Tao on their performance. Both of these experienced observers noted issues with their Miyauchis, but were generally satisfied. Here is my experience.

The Miyauchis are indeed small and light compared to the Fujinon. Held above your head, you would guess they weigh half as much as the Fujinons, and they are very comfortable to hold. They also come with a beautiful brown leather case that is easily the finest I have seen for any binocular. The binoculars themselves look great, too, although a close inspection shows that the finish on the silver metal parts is perhaps not as even as it could be. The maroon leather is very nicely done.

The coatings seem a nice dark green, although they do not quite have the apparent quality of the Fujinons. More seriously, there was a slight haze on the inside of one of the 3 element objective lenses, and there were a couple of faint wipe marks on the inside of the other lens. These flaws are really unfortunate, and would be reasonable grounds for many customers to return for a refund. Additionally, when looking through the objective lenses towards the prisms and eyepieces, there were uneven areas on the prism coating. It looked as if circular areas on the center of the prisms were well-coated, but that outside this circular area the coatings had a mottled appearance. I have not seen anything like this before in a binocular. Perhaps it has no effect on the view if the areas I describe are out of the light path, but really it is another thing you don't like to see in an expensive binocular. Additionally, the prisms seemed much smaller than the Fujinon's, although this may be a consequence of the unusual porro-II arrangement of the Miyauchi.

These faults sound bad, but I was ready to overlook them if the Binons performed well. First views outside were promising - the view is indeed impressively wide. A neighbor and my dad both really liked them, as did I. Then, however, I sat down for a rigorous comparison with the Fujinons. On looking at a tree trunk in the middle distance, it was clear that the Fujinon showed more detail in the center of the field. Not much more detail, but there was a clear difference that I expect anyone who compared both would see. Here my experience is different from Holger Merlitz's, so perhaps this is a sign that I did not get as good a pair. Additionally, although the field is certainly smaller in the Fujinon, a much greater proportion of the field is sharp. The result is that when viewing a telephone pole in the near distance, a greater area of the telephone pole could be seen clearly without moving the Fujinon than could be seen in the Miyauchi.

The asymmetrical distortion of the field that both Merlitz and Fan Tao found in their pairs was present in mine as well. The lower portion of the field of view held its sharpness until near the edge, very much like the Fujinon, while the upper portion of the field became blurred really not very far at all away from the center. Color rendition was better in the Fujinon as well - a stone wall in my yard appeared more yellow in the Miyauchi, and early spring leaves were a more golden green compared the pure colors found in the Fujinon.

Still, the Miyauchis are wonderfully light, it is hard to overstate this advantage over the Fujinon, so I looked forward to the evening. At night the same distortions noted in the day were even more obvious as star images showed much more blurring in the upper half of the field than in the lower. Still, the field is very wide and impressive. There is a final problem, however, which really clinched it for me that I had to return the Miyauchis. The field is not perfectly round. It is close - indeed I did not see this fault in the daytime, and only confirmed it the next morning - but the field is not circular. The bottom of the field is flatter than it should be, and darkening is visible near the bottom, making the edge of field indistinct. I have never seen anything like this in any binocular and hesitate to speculate on what the cause may be. Perhaps the prisms are simply too small to illuminate the whole field; perhaps the light path from both objective tubes is misaligned. Perhaps it is something else entirely. Whatever the reason, I found the effect very distracting at night, and in the day once I was aware of it and started inevitably to look for it. The light cutoff, the distorted field of view, and the optical problems mentioned earlier combined to make an unsatisfying experience, so I was happy to be able to return the Miyauchis.

I write this report with something of a heavy heart, because I had long searched for a wide-angle, low-power binocular like the Binon, and was thankful that Miyauchi had listened to our small hobby and catered to our needs. I was prepared to put up with distortions in a widefield binocular, I understand this is unavoidable when working at what must be something like f3. Still, I don't think it should be too much to ask for the distortion to be symmetrical and for the field of view to be circular in a binocular that costs nearly $700. Again, I bought these used, and there does seem to be some variation, but if you are still interested in trying a pair of these I would make sure to discuss the possiblity of a return.

Now I only hope that my Fujinons will forgive my brief infidelity. I tried to make it up to them by ordering a new pair of 10x50 FMT-SX, just now available for sale here in the US. I'll give a report on these after I have a chance to try them out.
Nils Schoultz

#8 lighttrap

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Posted 28 April 2005 - 07:45 PM

Nils, Welcome to CN! It's great to see you contributing here. I hope you'll be a regular contributor. Definitely, please post your views on the Fuji 10x50 to this forum. A lot of us, definitely including myself would really like to see some experienced reviews of these.

Mike Swaim

#9 holger_merlitz

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Posted 28 April 2005 - 08:03 PM

Hi Nils,

Thank you for your detailed and critical report on the Miyauchi Binon. Your findings indicate that a couple of things are not yet properly under control. We have to acknowledge that the construction of a good 7x50 wide angle is especially difficult, much more than it were the case for a 10x50. Still, for that price tag, we can expect that Miyauchi has solved those technical problems to an extent that pleasant observations become possible.

The unsymmetrical (Kobayashi-spectacle :-) effect can be regarded as finally confirmed now. It seems that they are tilting the prisms a little bit to shift the sharpest part of the field downwards from the center. In my Binon, the center of sharpness was shifted just a little bit, perhaps one degree (out of 9.5 degs. field) downwards.
For terrestrial observations this actually makes sense, because the upper part of the image is hardly used. In astro-observations this is a little annoying. Also, if the prisms are tilted too far, the field of view won't be round any more, as you have observed. This is not acceptable. It is quite strange to me how this can pass the end control. They must have seen that, no doubt. I really would like to hear a comment on that by Miyauchi.

Regarding the center sharpness I could detect no differences to the Fujinon. Both displayed nicely sharp and pointlike star images. If in your Miyauchi the prisms were tilted a lot, then the 'center of sharpness' might have been quite far down towards the lower edge of the field. Or, perhaps, in such a case distortions grow so much that the sharpness is affected all over the field. You have done correctly to return that glass - it was out of function.

I still believe that this is an extraordinary instrument. But your observations indicate that we have to keep an eye on that unsymmetrical field-issue. This should not be the duty of the customer but that of the producer, especially, since the built quality and the price are placing this glass into the high end region, were it has to compete with products as perfect as the Fujinon. I think the ball is with Miyauchi now to clarify some points.

Best regards,
Holger




#10 hvezdar1972

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Posted 29 April 2005 - 08:45 AM

Hi guys,
Thanks for reading my first post, one always wonders if anyone is interested.

I think you are probably right, Holger, that it is the same tilting of the prisms that is behind two unusual traits of the Binon: the shift in the center of sharpness towards the bottom of the field and the light cutoff at the bottom. I'm also afraid that you are right that these effects are intentional. If so, I think it is a real mistake; it is hard to imagine a designer thinking that the positive results of this would outweigh the negatives. Maybe my pair was worse than yours, though. Do you see the same light cutoff at the bottom of the field that I do?

It's a shame because I really wanted to like these and was willing to overlook all kinds of small faults to keep them. Back in March I went camping in the Anza Borrego desert in southern California, and spent a lot of time on a cot in a full sleeping bag (cold!) with only the Fujinons and a small bit of my face pointed up at the sky. For me this is still the most exciting experience in astronomy - more inspiring than any view of anything in a telescope. Just before dawn, the summer milky way rose into view, and I could follow it from the summer triangle all the way down into Sagittarius and beyond. This was really something special for me, as I think Mike knows, here in North Carolina there are so many **** trees that you have to go out of your way to a lake to see the southern milky way. I also lived for a semester in Mainz and for 3 years in the Czech Republic, Holger, so I have experienced what it is like in the summer in Europe to wait forever for it to get dark enough to observe. I hope you get to have a look at the southern sky with binos someday if you haven't already. For now, I still think the Fujinon 7x50s are the best for this - the 10x50s are for my light polluted back yard and because I can't resist a nice pair of binoculars. Oh man, it's almost 10am, I need to get to work!
Nils

#11 holger_merlitz

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Posted 29 April 2005 - 09:22 PM

---------------------
....I have experienced what it is like in the summer in Europe to wait forever for it to get dark enough to observe...
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Hi Nils,

Even worse: In Germany there are hardly more than 30 usable nights a year - the rest is cloudy or misty :-(

Through my Binon, at least the field looks circular and I did not notice any light-cutoff. I believe that your case was extreme, and in a second attempt you may be able to receive a Binon in working condition. Nevertheless, I would as well prefer to have a binocular that is collimated in a perfect symmetrical manner. In my opinion a tilt of the prism should not become a feature, even if there were a few positive results coming along with that.

We should try to figure out how to make Miyauchi deliver an official statement on that issue. People who have purchased (or who are planning to purchase) a binocular of this price class should not be left uncertain about the collimation features of their instrument.

Best regards,
Holger

#12 lighttrap

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Posted 29 April 2005 - 10:55 PM

Even worse: In Germany there are hardly more than 30 usable nights a year - the rest is cloudy or misty :-(


Same here in central North Carolina, USA. One learns to optimize one's equipment for the rare times stargazing in such an environment. Judging from the reports I see from the UK, Belgium, Canada and Sweden, it's probably more common than not, for am astro to be an infrequent indulgence. In the US, as large as it is, only a relatively few locations are really suitable to extremely frequent good conditions. Yet, not surprisingly, folks who enjoy such frequently good conditions often seem to make up the bulk of participants on forums such as this one.

#13 Guest_**DONOTDELETE**_*

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Posted 30 April 2005 - 02:09 AM

Even worse: In Germany there are hardly more than 30 usable nights a year - the rest is cloudy or misty :-(



I was kind of depressed today, but I'm now feeling blessed.... boy, 30 nights a year.... How can you live with that?

#14 DJB

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Posted 30 April 2005 - 03:50 AM

Hi guys,

I don't know, but I received a later version from Kevin at OBERWERK in 2005FEB. I agree with the upper-lower field aberrations, but, otherwise, I don't have a problem with my unit. I sorta like the effect. Get an older JASON 7x50mm UWA, circa. 1960's, and compare. You will see! Nice field unit tho, as are the JASON's 7x35's, Model 138, as I recall.

It must have been a bear to even contemplate the optical design of this beast [because of the limited interest for this type of binocular for astronomical purposes]. Perhaps we should be happy with what has been offered???

I have worked for the U.S. military in VLS optics, similar to applications for the HST mirror. Can't go any further than that guys. Black Hole stuff, you know.

However, if we could have produced a beautiful "plastic" UUWA mirror for aircraft simulation to this spec, we would have been entirely happy with the product. We could not! Different animals, of course.

A great success for Miyauchi, I say. Made in Japan. China couldn't even consider this type of instrument at this time. However, China's optical coating processes are (getting) more sophisticated these days. I think China will make the grade, with our help.

I am sure we are making a mountain out of a mole hill here, guys, as my grandma used to dictate.

Is there anything else on the market similar to the Binon?
I do not know of any other CURRENT product. Please advise, if you know. Will appreciate the input.

Take care all, and CLEAR skies.

Dave.

#15 holger_merlitz

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Posted 30 April 2005 - 04:46 AM

I agree, Dave: The Binon is perhaps the best binocular of my collection (with its closest competitor being the CZJ 8x50 Nobilem Super). No doubt it is a great achievement by Miyauchi, and, to reset the measure: The edge-unsharpness through the Binon is significantly less than that of the 10x50 Zeiss Dekarem/Jenoptem, just to give an example. Its image is very bright and central sharpness is excellent. And: There is currently no other 7x50 wide-angle on the market. Last not least: It looks cool!

I believe that something was wrong with Nils' item. But we all of us have observed that asymmetry in collimation, which is unusual, has not been mentioned by Miyauchi, and I do not appreciate that and would like to know whether it is a defect or a supposed-to-be feature.

Best regards,
Holger

#16 DJB

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Posted 01 May 2005 - 12:59 AM

Hello Holger,

Thank you for your comments, as I hold you in high regard.

I agree with you, and I, too, wish that Miyauchi had informed the would-be purchasers if this asymmetry were intended or not, i.e., is it actually a "design feature."

Kevin at BigBinocular believes that it is, and, at this time, I would have to agree.

Take care and regards,

Dave.

#17 Neil Weiner

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Posted 01 May 2005 - 08:02 AM

Maybe they miscalculated the length of the optical path, and had to put it through the tubes at an angle, to fit it inside.

#18 holger_merlitz

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Posted 01 May 2005 - 09:15 AM

Hi Neil,

The opticians at Miyauchi are no beginners :-)

The construction of a compact wide angle 7x50 is extremely difficult, much more so than (for example) to construct a wide angle 10x50. That's the reason why all current 7x50 binoculars come with 7 to 7.5 degs., including Zeiss and Fujinon, whereas the Miyauchi has 9.5 degs. Earlier attempts to construct wide angle 7x50, as by Tasco, ended up with extreme close-to-edge distortions, much more than in the present Miyauchi.
So I guess they knew what they were doing, and the asymmetric collimation was perhaps no accident.

Regards,
Holger

#19 EdZ

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Posted 01 May 2005 - 09:31 AM

the asymmetric collimation was perhaps no accident.


I have seen this assymetric appearance in some other binoculars. I would consider this a misalignment and not by design. I can think of no valid reason why, by design, the light path would be moved off of the preferred optical axis, that which passes thru the center of all lenses.

In at least one case you have observed that this off axis path has resulted in a less than round exit pupil. In one case I have observed the same result. In fact, in my case it was significant and resulted in a loss of potentially 10-15% of the light.

I wonder whether a premier binocular repair shop would find that such a condition is a result of the need to tilt prisms to compensate for objectives that are not set exactly perpendicular to and centered on the mechanical axis?

edz

#20 holger_merlitz

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Posted 01 May 2005 - 08:27 PM

Hi Ed,

but why then have several people made identical observations: Each time the sharpest part of the image was shifted below the center of field, never to the left, right or above. Just by chance?

May be. May as well be that Miyauchi was trying to reduce the impact of edge-unsharpness (a result of the unavoidable field curvature in such a wide angle f 3.2 device) for terrestrial observations. A weird approach, in fact, and not the one I would like to see. Anyway, this tilt seemed to be small in all cases except for Nils' binocular, which was apparently defect.

We may need a little more statistics. So we shall wait a couple of months and see what other users are going to report on that issue. And hopefully by then Miyauchi will be willing to give a comment.

Best regards,
Holger

P.S.: Nils: Do you have by any chance recorded the serial no. of your Binon?

#21 EdZ

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Posted 01 May 2005 - 08:56 PM

Holger,

It does seem odd that several would see the same thing. I suppose there is a possiblity it is done purposely.

In the worst case binocular that I tested, the maximum exit pupil center was 40% inward at the 7 oclock position on the right side and at the 4 oclock position of the left side. But what was most significant is directly opposite that off-center exit pupil, the objective at 20% from the edge was providing no illumination of the exit pupil at all. This moving the exit pupil off center can cause significant light loss, IMO not a positive condition under any circumstances.

Somewhere in the forums there is a link to a plot I posted quite a while back showing the condition of the binocular I reference. it can be found thru the best of links referenceing vignette or illumination of exit pupil.

edz

#22 hvezdar1972

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Posted 02 May 2005 - 08:55 AM

Hi,
The Binon I had was serial number 71. I'm glad other people are happy with theirs; it seems there must be some variation. In my pair, there was a clear difference in center sharpness compared to the Fujinon. At night on the stars it was not so noticable, although it was slightly quicker and easier to find optimal focus in the Fujinon. The difference was in the daytime. A richly detailed subject (I used a partially shaded tree trunk in the middle distance) seemed to show infinite detail in the Fujinon, not so in the Miyauchi. Perhaps this could be partly attributed to the comparatively golden color cast of the Miyauchi, but I don't think entirely.

I think Holger's mention of the 10x50 Dekarem is interesting. Apples and oranges, I know, but I hope it will demonstrate that I am not being too harsh on Miyauchi. I love the Dekarem. I've had several pairs, because when I lived in the Czech Republic they were easy to find beat up / out of collimation / with haze on the prisms for not very much money. It was fun to fix them and give them as gifts, because they really are a fun binocular, unlike (for me) the Binon. The field in the Dekarem is a full 72-73 degrees, which gives a much more immersive feeling than the 66-67 degrees of the Binon. Yes, the outer portion of the field is not at all sharp in the Dekarem, and stars can't really be called stars at the edge, but the edge is way, way out there. I don't mind the tradeoffs in the Dekarem at all, in fact I really like them. If the Binon had given a similar experience I would not be complaining, I would be singing its praises.

Defects can happen to any company. I hold Swarovski in very high regard, but I once bought an 8x50 slc that arrived with an internal fog on an objective lens, supposedly caused by outgassing from the prism coatings. I forgave Swarovski (their 10x42 slc is my current favorite bino), and could have forgiven Miyauchi for the haze I found on the inside of the objective lens on the Binon. The wipe marks, however, are a different story. I've never seen a new binocular with wipe marks on internal optical surfaces - indeed I would be surprised to find this on, say, a $130 Nikon or Pentax made in China. To me this and the shoddy prism coatings do not speak at all well for the way Miyauchi puts things together. This is a separate issue from quality control, where we have to accept that we are all human beings and sometimes a bad apple slips through. It seems to me that there are deeper problems than quality control, and I would be reluctant to buy another Miyauchi product.

Again I've ended up sounding harsher than I intended. I'm glad other people's Binons have been better.
clear skies,
Nils

#23 holger_merlitz

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Posted 02 May 2005 - 09:53 AM

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The wipe marks, however, are a different story ....

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Hi Nils,

My experience is that the star test is the most sensitive test for image sharpness. Being mathematical point-like sources of high contrast, star images reveal faults that remain invisible during daylight observations. Also, during night our eye-pupils are wide open, so that we include the outer parts of the exit pupils, which often show more problems than the innermost 3mm during daytime. Therefore I am not sure what kind of fault you have observed with your tree-trunk test, whereas the star images appeared point-like. I did not find any color tint in the Miyauchi which could have biased the contrast. Also, both images, that of Fujinon and Binon, were of similarly high brightness. Perhaps some stray light from a bright light source just outside the field? In this case, one may repeat the observation from various different angles - it may be, that one binocular is sensitive for stray light under one particular incident angle, whereas another binocular responds to incoming light from other angles. It may be that on sunny days a lens-hood were a useful addition to the Binon, which objectives are quite exposed just a few mm behind the rim of the ojective tubes. But if you have observed haze on your lenses, then this could as well have been responsible for your observation, and in this case it were a defect of your particular device, not an indicator for the performance of the Binon in general.

According to your description, with cleaning marks, it sounds as if your Binon was returned by another owner before, who had already tried to clean it and messed it up. If so, your distributor made the mistake to sell it again - this was then not Miyauchi's fault. Whatever reason, I would suggest you to get another one which is functioning, then go out and enjoy :-)

Regards,
Holger

#24 hvezdar1972

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Posted 02 May 2005 - 10:18 AM

Hi Holger,
This sharpness issue is the part of our story that I find the most difficult to figure out. Whatever its problems, my Binon was in perfect collimation, and the haze in one objective did not result in the view on that side being any dimmer or less sharp than the other. But yet there was more detail to be seen in the Fujinon, and I'm sure that if you had been there comparing with me, you would have seen the same thing. The difference was subtle, and took a couple of back-and-forths, but it was clearly there. So too was the light golden color cast. Not as noticable as the smoky yellow of the Dekarem and Deltrintem, but again certainly there. Regarding sharpness, I think your idea that the excessive tilting of the prisms in mine caused not only the darkening at the bottom of the field but also some other negative effects throughout the field is probably correct.

It is possible that the previous owner disassembled them, but I did not get that feeling in our emails. To take apart the Binon, mess with the 3-lens objectives, put them back and have them in perfect collimation would be quite a difficult task, certainly one I would not want to try myself.
best wishes,
Nils

#25 OBERWERK

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Posted 02 May 2005 - 12:42 PM

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According to your description, with cleaning marks, it sounds as if your Binon was returned by another owner before, who had already tried to clean it and messed it up. If so, your distributor made the mistake to sell it again - this was then not Miyauchi's fault. Whatever reason, I would suggest you to get another one which is functioning, then go out and enjoy :-)

Regards,
Holger


I don't know the history of this binocular, but as the only US distributor of the Binon (that I'm aware of), I just wanted to clear some things up. 1) We've only had one return on this model, and it's sitting on my desk right now. 2) I look at every one of these before shipping. On a few occasions, fine collimation was done (very fine)- but it's simple to do externally with a 1mm allen wrench. 3) I've never opened one of these up. 4) I would have noticed flaws or smudges on the coatings had it come from the factory that way.
Kevin Busarow
www.bigbinoculars.com


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