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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Zeiss Conquest 10X42 HD-AllBinos Review (1 Viewer)

elkcub said:
David,

That's very interesting, particularly since the one issue that probably causes more headaches than any other is collimation. At least that's been my experience.

Are you poo-pooing the limits specified in the SPIE Field Guide to Binoculars and Scopes? It seems like you're talking about at least an order of magnitude difference.

Ed
Click to expand...

Ed,

Using a roof for usually less than 5 minutes at a time is going to be very different hours of serveilance with a porro. Bescides those two, I've probably only seen a handfull that felt like they were giving me immediate eyestrain out of many hundreds I've tried.

I've not found the notes I made at the time, but it my memory serves me right, out of 5 roofs I tried with this method, the maximums I got just under half a degree (~25 arcminutes) convergence. 1.3° (78') divergence and 2° (120') dipvergence. Given the crude method, the dipvergence would be least reliable.

That miltary spec has no tolerance for convergence, but we've been told convergence was deliberately employed for an Avimo British/NATO binocular. My divergence value is about two and a half time the military max and I accept my dipvergence figure may be high.

The SPIE field guide says civilian binoculars may exceed those limits so I see nothing particularly contradictory in the values..

The point I was making about those two I received with obvious dipvergence was that, for me the centre performance was unaffected as far as determine, and although I could easily see the misalignment, I could comfortable ignore it as well. You may well differ, but if my test is at all representative of mid range binoculars ( and I accept it may not be) then most users would appear to be quite tollerant.

David
 
Does anybody else have a problem with the meaning of the terms "divergence" and "convergence"? For me, when applied to binocular collimation, they have the opposite meaning of what they seem to mean. That's because they refer to the rays emerging from the eyepieces, not to what the eyes see. So, convergence is the one that forces the eyes to toe outward and divergence is the one that is easily corrected by the eyes toeing inward.

Here's a link (hopefully page 326) showing the nonparallel rays exiting the eyepieces and the eye movements required to correct them. Looks like you have to scroll up a little to see the figure. Notice the reference to Bill Cook's definition of "conditional alignment".

https://books.google.com/books?id=i...ular collimation meaning of divergent&f=false
 
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Hello Henry, seems perfectly logical to me. The converging rays will eventually meet, the diverging rays will get further apart and never meet. It is consistent with considering the binocular as an optical system.
Should add it is over 50 years since I studied "A" level physics in the UK so conventions may have changed. I will be meeting my wife's cousin's husband - a retired professor of optometry- in a couple of weeks time. Happy to share his thoughts if required.
 
Henry,

I hadn't really thought about it, but I'd agree it sounds the wrong way round. My numbers are as illustrated in the the Yoder book. I'm just wondering if the SPIE values actually make more sense the other way round?

David
 
henry link said:
Does anybody else have a problem with the meaning of the terms "divergence" and "convergence"? For me, when applied to binocular collimation, they have the opposite meaning of what they seem to mean. That's because they refer to the rays emerging from the eyepieces, not to what the eyes see. So, convergence is the one that forces the eyes to toe outward and divergence is the one that is easily corrected by the eyes toeing inward.

Here's a link (hopefully page 326) showing the nonparallel rays exiting the eyepieces and the eye movements required to correct them. Looks like you have to scroll up a little to see the figure. Notice the reference to Bill Cook's definition of "conditional alignment".

https://books.google.com/books?id=i...ular collimation meaning of divergent&f=false
Click to expand...

Yeah, it's a perfect example of not living beyond the exit pupil. In this case the terminology satisfies the optician, even though the tolerances were based on the human observer. One gets used to this, Henry, but it does give me a chuckle for you to bring it up. ;)

The figure below was taken from S. Ebenholtz' "Oculomotor Systems and Perception." (2001)

Ed
 

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Post #43, The-Wanderer. Sorry I can respond only now. In the meantime first Typo, then others in another thread, have done so. During that time I sought for facts from a few sources, including my eye doctor in a phone call of about a minute as he drove to work in the morning (he is personally known), but without much clarity.

FWIW, it seems that a pupil whose dark-adaptation is limited by age is dilated beyond that limit by the eye drops. These may fail to do that if dilation is limited by diabetes.

About measuring methods I learnt a lot from the responses here! My own is to peer at the bathroom mirror at night and shine a dim light at an angle quickly. This takes some practice, with the small LED in a cell phone dimmed more easily than a flashlight, and precision is poor as I just guess to the nearest mm looking at a scale immediately.
 
Adhoc,

Thanks for clarifying that point.

Back to collimation.

Looking at various articles on line I realised there is another point of potential confusion. The angle made to the objective axis will differ from the angle made to the eyepiece by the magnification and it's not always obvious which the author means. In Bill's article he posted here he refers to the 1977 Ostrovskaya study where "the maximum allowable deviation from parallelism" was 30' dipvergence, 40' divergence and 100' convergence. He states the Navy standard he worked to was 2', 2' and 4'. Seems a curiously large difference. https://www.google.co.uk/url?sa=t&s...Sfvlh-D-_mttJbBug&sig2=KDPLyMPIFjhZ8NJOPc8lOg

So was the Navy standard massively over specified? If you look at page 40 of this Tonkin article, for a 10x binocular he gives figures of 1.5', 2' and 4.5' for the real collimation limits which are very similar to Bill's Navy values except he points out that these should be multiplied by the magnification to give the actual tollerances of 15', 20' and 45' or roughly half the Ostrovskaya values.
https://www.google.co.uk/url?sa=t&s...-1ZIggwJSY9SguzYg&sig2=58wmbY6R_-JumjhXct2eMQ

It seems to beg the question, was Bill's Navy specification twently fold better than the Ostrovskaya tolerances or two fold?

David

P.S I found a reference to the ISO collimation standard for high quality binoculars in an old post by Surveyor. "Note that ISO 14133-2-2006 for High Performance Instruments shows acceptable edge limits of divergence in the vertical of 20’, divergence in the horizontal of 60’ and convergence of the horizontal of 20’."
http://www.birdforum.net/showpost.php?p=1046458&postcount=7
 
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David,

Looks like some genius at the ISO finally realized that expressing collimation errors in minutes of apparent angle rather than real angle greatly simplifies the standard since it doesn't vary with magnification.

The old Japanese Telescope Inspection Institute (JTII) had what must be the strangest system of all (as represented in J.W. Seyfried "Choosing, Using, & Repairing Binoculars", pages 149-150).

Collimation limits were "...expressed by the value of real angles in minutes...", but magnification was represented by broad ranges: Under 4.5X, 4.5X to 10X, 11X to 15X, 16X to 20X.

The limits for 4.5X to 10X were: Vertical 4', Divergent 10', Convergent 6'.

Under this system 10X binoculars are held to a very lax standard when expressed in apparent angle: Vertical 40', Divergent 100', Convergent 60'.

Did you notice footnote 3 in the first link of your post #67 Apparently we can't even count on consistent definitions of convergence and divergence!

Henry
 
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I'm certainly confused. Just to add another uncertainty, the ISO standard was updated this year but I've not found anything about what might have changed.

David
 
In the midst of ever-growing opto-mechanical confusion/consternation, I would suggest that the root demand is to stay within human observer tolerances. If an observer attempts to align his/her eyes simultaneously with each of the optical axes of a binocular, then convergent axes force the eyes to diverge. Here, there is no acceptable tolerance, because human eyes are simply not designed to do so. If the axes diverge, then the eyes must converge. That's ok. Note, however, that the SPIE specs indicate a minimum of 5 to a maximum of 30 arcmin. That's interesting, why a minimum?

At optical infinity aren't the optical axes of the eyes perfectly parallel? Actually, not. Convergence and accommodation are physiologically connected through an adaptive feedback control system. Resting eyes tend to accommodate by about one diopter, so some amount of convergence also occurs sympathetically. My guess is that the binocular specs cater to this property of the visual system, recognizing that individuals differ and can also adapt the tonic state of their feedback controller. Binoculars are simple; humans are not.

Anyway, as stated, the SPIE specs are independent of magnification. Something's got to be simple.

Ed
 
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Ed,

I hope we can agree that our eyes are more tolerant of convergence, being part of normal function. I think it's safe to assume the larger of the horizontal figures refers to convergence from the viewer's perspective. Adjusted accordingly, the maximum viewer convergence limits would be:

Ostrovskaya 100 arcminutes
JTII 100 arcminutes (10x)
ISO (high quality) 60 arcminutes
Tonkin 45 arcminutes
SPIE 30 arcminutes
Bill 4 arcminutes

My worst estimate 79 arcminutes

I understand the big name manufactures are represented on the ISO comittee, so from 2006 onwards this would be gradually be adopted as the worldwide civilian standard. (I guess it's possible civilian Fujinon IFs are made to military spec as well.)

It's likely there is a lower specification standard for 'general use' binoculars as there is for other parameters, but we don't know what that is.

What I have noticed in the last 5 years is that the apparent resolution of modestly priced binoculars has significantly improved and the ones I've tested now meet the 2006 ISO 'high quality' standard and may do for the other parameters as well. One of my test group probably predates the adoption of the ISO and could be JTII, and it's possible one of the others might be made under the 'general use' specification. My estimates may not be particularly accurate but the horizontal values all fall within the Ostrovskaya and JTII limits and seem fine to my eyes.

David
 
Hi David,

Yes, we certainly agree that the eyes are anatomically more "tolerant" of convergence than divergence, and that the latter should be prevented. This is accomplished by imposing a minimum 5 arcmin convergence demand on the eyes. The dipvergence spec of ≤ 5 arcmin is really bidirectional around zero, so the manufacturing range is ± 5 = 10 arcmin.

Military standards are significantly effected by anticipated combat task performance, e.g., enemy aircraft detection, shipboard horizon scanning, long-range tank surveillance, etc., and for that reason don't cater to "relaxed" viewing that a birder might appreciate at shorter distances. I would imagine that astronomy uses might also be more demanding of parallelism, although I should avoid saying anything about that domain. In any event, Bill's demanding spec of 4 arcmin probably reflects that kind of military requirement (although I don't recall him stating it).

I have little doubt that mid-priced products are getting better, and will continue to do so. A big incentive, I suspect, is the prospect of large military contracts, which increasingly favor low bid off-the-shelf products.

Ed
 
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All I can say about this particular set of binos is that they are amazing for the price. Super clear, nice colors and as it starts to get dark, you can see with the least amount of light. It's crazy so go pick you up a pair and let it blow your mind. I picked up a new set last week and they wow'D me!!!
 
typo said:
James,

I'm glad you now understand the crux of the issue.:t: ;);)

Seriously though, this is something the industry needs to sort out. The ISO standard all of the big companies did allow 'high quality' binoculars to have a full objective resolution that is roughly 2 fold worse than the diffraction limit. If most of that aberration is confined to the peripery of the objective that wouldn't be much of a problem, as that is blocked by the iris of the eye in bright viewing conditions. However if the aberrations were more uniformly distributed then it means that those with 20/15 vision should be able to pick up the problem with poorer samples. You would probably need to be 20/12 or better for the worst of those samples I saw. That's less than 10% of the population. I've now tested a few £200 binoculars that would match the premium models for effective resolution and easily beat those Conquests I tried..

I did discuss the problem with one of the senior people at Zeiss a couple of years ago and he assured me they would be developing a new QC protocol, but I don't know if that would cover their binoculars made by third parties.

The ISO standard was revised earlier this year. Bizarrely for 8 and 10x42s the "high quality" limit was actually relaxed to 2.5 times worse than the diffraction limit. Expect more dodgy binoculars in the future.

David
Click to expand...

The Conquest 8x42 HD measured 4.7/4.7 centre resolution in arc seconds. How does that compare with the alphas ?

https://www.all4shooters.com/en/Shooting/optics/Zeiss-Conquest-HD-8x42/
 

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Maico,

Until recently I would have said that a value of 4.7" would be typical for all alpha 10x42s, and indeed everything over about $300. I do find those values surprisingly uniform. Generally a 4.7" would result in an effective resolution that would be totally satisfactory for at least 95% of users, but the particularly eagle-eyed might spot some variation at this level but they might need a tripod to do it. I got an assurance from one of the big names that they would be revising the QC for their top models at least and to my eyes at least, things appear to improved in the last year or two. Indeed others appear to have recognised the problem as well and it appears to me that <3.5 for a top line model should be expected. This will make to practical difference for most users.

Troubador said:
And what does that mean for seeing a supercilium on a warbler at 20 metres or the wing-tip pattern on a gull at 50 metres or the smile on an otter's face at 30 metres ? Etc.

Lee
Click to expand...

Lee,

From your past comments on the forum, it probably makes no difference to you at all, but others might be able to do those things at considerably further range.... if the binocular is good enough.

Belated Happy Chrismas and hope you have an excellent new year.:king:

David
 
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