What binoculars do you think have the most WOW factor! (3 Viewers)

[Binastro]

Thank you very much for that current information.

Very recently, though, I was informed that although the wavelength errors might be good with the best machine polishing the actual surface finish is not good enough for critical work, such as with lasers.
Also now there is a critical shortage of top optical technicians able to do the highest quality hand work.

Some Russian tank Maksutov optics were reputedly finished to 1/20th wave.

And the lower priced Chinese binocular optics except when monitored for firms like Nikon, are pretty awful.
They are not in the same class as common Soviet export binoculars, despite fancy exteriors.
Some of the better Chinese binoculars are good.

I yesterday tried a Japan Bausch and Lomb 10 x 42 Elite phase coated 1994 maybe and it outresolves a very recent highly thought of binocular.
Also it has less chromatic aberration.
It is well used but with perfect optics.
The transmission is less than a modern equivalent even though I see no sign of haze.
The modern binocular is brighter despite the Elite having nice multicoats.
I cannot make up my mind if the objectives are doublets or triplets as there seem to be two cemented surfaces.
Jupiter looked perfect in it and the moons were if anything better seen than with the modern comparison.

 

[james holdsworth]

Thank you very much for that current information.

Very recently, though, I was informed that although the wavelength errors might be good with the best machine polishing the actual surface finish is not good enough for critical work, such as with lasers.
Also now there is a critical shortage of top optical technicians able to do the highest quality hand work.

Some Russian tank Maksutov optics were reputedly finished to 1/20th wave.

And the lower priced Chinese binocular optics except when monitored for firms like Nikon, are pretty awful.
They are not in the same class as common Soviet export binoculars, despite fancy exteriors.
Some of the better Chinese binoculars are good.

I yesterday tried a Japan Bausch and Lomb 10 x 42 Elite phase coated 1994 maybe and it outresolves a very recent highly thought of binocular.
Also it has less chromatic aberration.
It is well used but with perfect optics.
The transmission is less than a modern equivalent even though I see no sign of haze.
The modern binocular is brighter despite the Elite having nice multicoats.
I cannot make up my mind if the objectives are doublets or triplets as there seem to be two cemented surfaces.
Jupiter looked perfect in it and the moons were if anything better seen than with the modern comparison.

Binastro,

I have owned [and loved] that 10x42 Elite of which you speak, and agree with your assessment. I still have the 7x36 and find it so close to current alpha quality to be almost negligible. It is less bright, but no less sharp, contrasty and colours are rich and saturated.

I have said it before, the phase-corrected Elite's from the 1990's should be given serious consideration by folks considering older alphas, as the B&L's were better than any of the big three offerings of the time.

 

[etudiant]

Thank you very much for that current information.

Very recently, though, I was informed that although the wavelength errors might be good with the best machine polishing the actual surface finish is not good enough for critical work, such as with lasers.
Also now there is a critical shortage of top optical technicians able to do the highest quality hand work.

.

The shift to molded lenses presumably sets a minimum economic quantity, as someone has to make and qualify the molds. As a possible offset, it is much easier to mold aspherics than it is to grind them. So it is possible to conceive of a 'worlds best binocular' that could be funded by enthousiasts.
Kickstarter, anyone?

 

[pompadour]

Steve(@_n_w), excuse my ignorance, which is the reason I ask these questions. Have seen it said several times in Bf. that among the binocular models of the best optical quality today resolution is refined beyond the limit humans can see. You find the Habicht 8x30 better than the the Nikon SE and EII in resoln. Is this difference seen only when used for astronomy, and not in terrestrial landscapes, even when fine detail is deliberatley chosen to test this? Also, what does a resoln. boosting test reveal that indicates performance in practical terms? Other than you I find several experts, and those knowledgeable in optics, using this method in Bf., and elsewhere in the internet.

 

[pompadour]

For all breathlessly following my quest to solve the Great Mystery "What is wow?" - it's off. Too complex. Value for money is a factor. Etc. Saw the light - or lack of same - in some posts - which make very good additions to this thread - in this other one, at posts #92, copied below, to 101, at least. Probably more elsewhere in Bf.

Of all the individually defined, subjective things we as users of optics apply to our optics is kind of an experience . When I see "wow factor" I think "wow" there that is again. I wonder what this user means by it. Another thing I wonder at a little bit is "blown away". Speaking only for myself here...my "wow factor" these days comes mainly in the form of "...wow look how good these things are for less than $..." I personally have gotten to the point where it seems any of the alphas have lost their wow as far as I'm concerned. The last real "WOW" I had was in 1988 when Leitz had morphed into Leica and the Leica Trinovid showed up. I had the chance to look at a Trinovid 8x32 and W:eek!:W. Kind of the same thing when I got a look at the first phase corrected Zeiss. I was not nearly into optics back then as I am now, and really did not see much need to upgrade anything. By the time I did, Pentax had the DCF WP with phase correction for less than half a Leica and I was wow look how good these Pentax are. I freely admit to being more than a little averse to spending alpha level $$ even if I had the cash in the bank .

These days the upper echelon of the mid price glass has gotten so good that I have to look pretty critically to pick out the differences that do exist in favor of the alpha class glass. However, the alphas sure do not "blow away" things like they did (at least not to me) when phase correction was a technically difficult and operationally demanding task, at least not as far as I'm concerned. One of the things I enjoy is handing a Zen Ray or a Theron or a Kruger to a somebody who says "what sort of a binocular is that" and watch their reactions when they find out it is indeed less than $500.

Not picking on anybody here, it is just that all of the subjective user defined issues that keep popping up are interesting.

 

[typo]

Steve(@_n_w), excuse my ignorance, which is the reason I ask these questions. Have seen it said several times in Bf. that among the binocular models of the best optical quality today resolution is refined beyond the limit humans can see. You find the Habicht 8x30 better than the the Nikon SE and EII in resoln. Is this difference seen only when used for astronomy, and not in terrestrial landscapes, even when fine detail is deliberatley chosen to test this? Also, what does a resoln. boosting test reveal that indicates performance in practical terms? Other than you I find several experts, and those knowledgeable in optics, using this method in Bf., and elsewhere in the internet.

Pomp,

It seems this is a fairly delicate subject and not everyone here agrees with my interpretation of what is going on, so don't take it as gospel. I've preached this story before, so apologies for the repetition.

For someone with good eyesight I've found that the apparent resolution of binoculars is frequently limiting, and it's quite possible to distinguish view quality differences where the apparent resolution is a little beyond the acuity limit of the eye.

Note I used 'apparent' in the statement above, because what you 'see' is not what is normally measured by boosted resolution methods. That is a value for the whole instrument, mostly governed by the overall accuracy of the full diameter objective. Valuable information in it's own right, however the image that reaches your retina is controlled by the diameter of your pupil. In bright conditions the light from the peripheral area of the objective is blocked by the iris. If your pupil is 2mm diameter in bright conditions then you would only see the image passing through the centre 16mm of the lens of an 8x binocular. It's the optical quality of this central region only that is relevant to what you see under these conditions.

Visual acuity changes with light levels. It's best in fairly bright condition when the pupil diameter is 2-2.5mm. It gradually decreases as the pupil dilates due to aberrations in cornea and lens of the eye and other factors, so our ability to evaluate the performance of the binoculars decreases as well.

I've checked out the full aperture, and stopped down boosted resolutions for several low and mid priced pairs and found that many of them are indeed limiting for my eyesight in the centre. In low light my eyesight is limiting.

I don't know how many, if any companies QC the optical performance of the central region of the objective, but I've been told that at least one well respected company does not.

I suggest that many users if not all would be able to detect differences in optical accuracy in bright conditions, and these differences may not be evident from full aperture boosted resolution testing which is more an average value for the whole system.

I don't look at the night sky, but it seems obvious that wide aperture performance is more relevant, but I've also seen reports that stopping down the objective to give a smaller exit pupil improves the ability to 'split doubles' with some instruments. That could be explained by either improved performance of the eye with a smaller EP, or eliminating peripheral aberration from the optics, or possibly both.

Ed Zarenski from CN wrote something about this some years ago.
http://www.cloudynights.com/documents/binoexit.pdf


David

 

[pompadour]

... in optics automatic grinding and polishing processes dosn't necessarily lead to superior quality. I can't find it at the moment but didn't we had a youtube video here some time ago, where a NASA technician explained how they found a automatic solution to copy the perfect way human hands grind and polish the mirrors used for scientific telescopes? If memory serves me right, she said that summed up minor irregularities caused by the human hand lead at the end to a higher degree of precision compared with conventional automatic grinding. Perhaps, someone can give a link to that video. ...

Steve, could this be what you remember: at http://www.stjohnsrasc.ca/mirror-grinding/feb-2001-talk.html search for word "mimic".

David, just as I'm about to post this and rush away I see yours. Thanks! Will be free only in some hours from now.

 

[Surveyor]

Hello Pomp;

I am going to disagree with David to some extent.

The eyes are the limiting factor.

I do agree with his measurements; just don’t agree with his application of the results.

The eye is subject to the same physics as a lens, and we do not know the limiting resolution of the eye. I have not been able to do a boosted, limiting resolution test of the eye but do know that the lens is capable of more resolution than acuity. Vernier acuity is as much as 10 times as high as normal acuity of random shapes, about 10 or 12” for average people. Most people may not be able to make out leaf edges at 20m but see the wires on a power line clearly a quarter mile, or more, away.

A camera and the eye are similar in the respect both have a lens and detector. The camera lens may have a resolution of 5” but the pixel size and focal length may be limited to 20”/pixel. The eye has the same problem because of lens and rod and cone arrangement.

If we look at a 16 mm stopped down lens, the Dawes limit would be 116/16= 7.25”. Multiply this by 8x and it becomes 58” at the exit pupil of the bino. If we just stop the eye down to 2 mm and apply the same math, 116/2= 58”. We can boost the binocular image, but that does not help the eye.

The acuity of the eye gets better as aperture reduces because effective focal length increases in the eye and overall aberrations are decreased. This is basically what optometrists’ measure when they dilate your eyes and get you to read the chart and then place pinholes of various sizes to check acuity and contrast.

Basically, I think David’s (typo) measurements and most conclusions are right, but the eye is the limiting factor, not the optics. I think, if I understand David’s setup and process (and not sure of this at all) then I think he is just using the bino as an adjustable iris. I think he would get the same results, minus magnification, by using an iris in front of the eye. The optic has the same light transmission and resolution, regardless of light level. The eye is the adaptive part and changes both optically and chemically for various light levels.

 

[ronh]

The water is so nice I can't help but jump in!

RonE said:
"If we look at a 16 mm stopped down lens, the Dawes limit would be 116/16= 7.25”. Multiply this by 8x and it becomes 58” at the exit pupil of the bino. If we just stop the eye down to 2 mm and apply the same math, 116/2= 58”.

I love it Ron! You have discovered a "mathematical identity" with this example, which also demonstrates that the normal eye actually does resolve to the Dawe's limit of it's modest aperture, at least at the optimum pupil opening of 2-2.5mm. Apparently retinal sensors are packed tight enough to cooperate with this ultimate resolving feat. This is not news to me, as I have read some things about vision, but your example puts the optic/eye coupling in a different light.

I think, however, that in some of your other arguments, you are ignoring the fact that many binoculars are optically flawed and don't resolve to theoretical limits, even stopped down. At least, that is the impression I get from reading Henry's reports of his binocular tests, in which many good models reveal defective prisms, large color error, pinched optics, and decentered elements. In such cases, redoing your example seems to indicate that what can be seen is worse than in the ideal case, with only the optic to blame.

Here's how I think the binocular influences what can be seen through it. If the binocular sucks bad enough, anybody can tell. If it is only slightly flawed, only people with good eyesight can tell. And if it resolves close to the theoretical limit, a person with good eyesight will be completely satisfied, because, by your example, the eye can then see exactly as well through the optic as without it, barring magnification.

Thanks to you and David for this discussion, even though you don't entirely agree! Let me guess, both of you disagree with me...
RonH

 

[Surveyor]

Hi Ron,

I agree optics can either be good or crappy. They can be worse than the eye but my point is that the eye does not change the optics, it can only see as much as the optics can deliver, usually less.

David did have one example of a bino that would probably limit the eyes. I do not remember the numbers now but the resolution came out to be something like 690/aperture or about 16" if I remember correctly, that one might limit the eyes on vernier objects, but I think most of use would find that an unacceptable example. Using standard MTF procedures, a boosted resolution of 16" would be in the 3% contrast range to start with. Nothing is going to help that, most of us find binos with with resolution of 200/aperture unacceptable. But even 16" is better than average acuity.

What I really disagree with is that the eyes stop down the binocular.

 

[Binastro]

Dear Surveyor, Ron and David,
I think all of you are right.

I think David has based his results initially on direct observation and tried to explain these observations by theory. Correct me if I am wrong.
Incidentally, persons with good vision can see a wire against the sky in the best conditions with a width of about 1.5 to 1.7 arcseconds. Some individuals better this.
This is much thinner than 10 to 12 arcseconds.
Draw a smiley face with a normal ball point pen, just a circle perhaps 3 inch diameter and similar pen mouth and eyes.
You will be surprised how far away you can see the face. In my case perhaps 12 to 15ft in normal room lighting. I suppose my pupils might be 3 or 4mm here? These lines are thin, but the eye can still make out the face but not resolve individual elements the width of the lines.
An additional factor in acuity is the fact that most peoples iris are not on their eyes optical axis.

I am quite happy to accept theoretical arguments and observational results, which may or may not agree.

I really accept all your conclusions.

As to binocular defects and eye defects. A skilled observer may see defects in a binocular which strictly speaking may conform to minimum optical standards.
And a skilled observer probably knows some of his or hers vision limitations.

Interesting if complex subject.

 

[typo]

If we look at a 16 mm stopped down lens, the Dawes limit would be 116/16= 7.25”. Multiply this by 8x and it becomes 58” at the exit pupil of the bino. If we just stop the eye down to 2 mm and apply the same math, 116/2= 58”. We can boost the binocular image, but that does not help the eye.

Ron,

What I think you are stating there is that the magnified resolution of a theoretically perfect binocular is equal the resolution of a theoretically perfect eye. I'd agree with that. The question is, in practice is how close each are to perfect?

I've used a binoculars of different magnifications and different apertures and theoretical resolutions apply, so I'll approximate the numbers to what it might be for an 8x. Two of my binoculars stopped down are as close to perfect (for the equivalent of 16mm) as I am able to determine with my crude boosted set up. That's within 0.5”on repeated measurements. Magnified 8 times that would be between 58” and 62”. Others are somewhere between 2” and 9” worse( 68” and 130”). In good light I can easily rank them for sharpness or apparent resolution.

For those not familiar with arcseconds, 20/20 vision is usually referred to as normal, 20/15 is quite typical, 20/8 is very rare but even 20/6 has been recorded. That corresponds to 120, 90, 48, and 36 arcseconds. (Obviously to explain that the pupil diameters need to be bigger than two millimetres for those last values, but that reaches the point where the optimum cone density is limiting.)

The best I can do with my good eye is ~65” in bright conditions (on a good day). Fudging the numbers as I don't know my pupil diameter, that's not as good as my best pairs but certainly better than several others. Explains to me why I can rank them for 'sharpness'.

David

 

[Binastro]

Regarding black threads against a light background, experienced observers with good sight can glimpse them with a width of about 0.8 arcseconds. Hold them steadily at 1.15 arcseconds and clearly defined around 1.4 arcseconds.
However, the astronomer Barnard was able to glimpse a wire against a daytime sky
with a diameter of 0.44 arcseconds. That is approximately 1 part in 500,000.
There are so many different types of resolution with variations here from less than 1 arcsecond to separating double stars without optical aid, typically 3 to 4 ARCMINUTES,
that it is difficult to apply these to the above.

It is a pity we cannot all switch to Hawk eyes mode when needed as they generally resolve 5 times better than humans.

 

[ronh]

"What I really disagree with is that the eyes stop down the binocular."

RonE,
Knowing you I expect as usual there's something deep about that assertion, and would like to understand where you are coming from. I don't want to kick up dust just for dust's sake, but the "fact" or "belief" that the eye can stop down the binocular is deeply ingrained in most of us, and is a part of our discussions all the time. Yet you, to whom we look for optical expertise, deny it! So, the point seems worth discussing.
I am going to give a simple argument in support of this status quo "understanding" that will probably insult your intelligence, but in hopes you'll pick it apart in some illuminating way.

The exit pupil, the bright round spot of light that appears in the eye lens when you hold the objectives up to the light, is a sharply focused virtual image of the objective lens. This can be confirmed by laying a ruler or any small object over the objective, almost in contact with the glass. Then, if a loupe is used to view the exit pupil, the test object will be seen clearly focused. The outline of the exit pupil is the image of the objective's edge, unless there are other more limiting internal stops.

If an aperture smaller than the exit pupil (like the eye's iris, contracted by bright light) is centered on the exit pupil, it will block light from the outer portions of the objective lens, just as it blocks the image of the outer parts of the objective lens in the exit pupil.

Am I missing something?
Ron

 

[Gijs van Ginkel]

Dear all,
I am a bit confused by the different examples and calculations, so I will try to understand how it works with the following deliberations (English is not my native language so I hope to express myself clearly). In the human eye blurring due to chromatic aberration and that due to diffraction are of equal magnitude and their combined effect is minimal when the diameter of the pupil is about 3 mm. A pointlike object, when focussed as sharply as possible, then produces a round spot on the retina with a diameter of approx. 5 micrometers. Geometrically this corresponds to an angular resolution of 1 minute of arc. This is the best resoltution that the eye is capable of under optimal conditions. With a pupil diameter of 5 mm the blurring due to diffraction is small, but the fuzziness due to chromatic aberration is larger than 1 minute of arc. Conversely, with a pupil diameter of 1 mm the fuzziness due to chromatic aberration is negligible, but the fuzziness due to refraction is more than 2 minutes of arc. In the fovea centralis the cones have a diameter of 1,5 to 2 micrometers, which corresponds to an angle of 1/3 minute of arc. So the "pixel size"of the fovea is just fine enough not to limit the visual resolving power. For images projected on the part of the retina with rods only or rod-cone clusters the situation is far worse, since the "pixel size"of the rod clusters or the rod-cone mixed clusters may be about 30-60 times larger than the "pixel-size"of the cones in the fovea centralis.
Gijs

 

[Surveyor]

The exit pupil, the bright round spot of light that appears in the eye lens when you hold the objectives up to the light, is a sharply focused virtual image of the objective lens. This can be confirmed by laying a ruler or any small object over the objective, almost in contact with the glass. Then, if a loupe is used to view the exit pupil, the test object will be seen clearly focused. The outline of the exit pupil is the image of the objective's edge, unless there are other more limiting internal stops.

If an aperture smaller than the exit pupil (like the eye's iris, contracted by bright light) is centered on the exit pupil, it will block light from the outer portions of the objective lens, just as it blocks the image of the outer parts of the objective lens in the exit pupil.

Am I missing something?
Ron

Ron, you just answered it yourself in your question. The only thing you missed is the part about the occluded edges. All the light in the bino exit pupil is in bundles, throughout the exit pupil, all principal rays of all the objects in the field stop pass through the center of the exit pupil as well as parts of the exit pupil the axis angle permits. This is why the eye can roam around a full exit pupil and see everything until you get close to the edge.

Henry Link and FrankD, the best objective and subjective reviewers on this site, along with many others, have made comments like those quoted below:

http://www.birdforum.net/showpost.php?p=2492973&postcount=10 Henry Link

“1) Greater viewing comfort: Large exit pupils are very forgiving of eye placement compared to small ones. I’m quite used to the easy view now, so ALL 4mm exit pupil binoculars feel overly sensitive to pupil placement.”

http://www.birdforum.net/showpost.php?p=2418624&postcount=7 FrankD

“1) …………………………………………………………………………I think it does help but I also think the larger exit pupil allows my eyes more room to roam around the image. I also think the increased depth of field provides a more relaxed and natural image for my eyes.”

http://www.birdforum.net/showpost.php?p=2529829&postcount=319 Chosun Juan

“Blackouts:
* Not really an issue for me, and my eyes were free to roam most of the field, even if not to the very edges before some darkening crescents began to appear. I should note, that it is my viewpoint, that set-up is fairly critical on this 10x42 bin. The combination of shallow dof, long ER (which I used fully), only 4.2mm EP, large oculars, and exacting Exit Pupil minima as I described, mean that ER, IPD, and Diopter settings, have to be precisely set, and eye placement, precisely positioned, in order to get the best view.”

These are just a few samples; but I have seen the comment repeated over and over again.

If the eye can roam around the exit pupil, it does not seem it is being stopped down by the eye to “match the pupil diameter, same as and 8x20”, does it?

As long as there is a full exit pupil, the binocular aperture is unstopped and full resolution and MTF are available in the exit pupil. If you physically stop the bino down then all the optical parameters change, f#, DOF, light cone, etc. None of these change when viewing with a 2 mm eye.

What is stopped down is the eye. The eye reacts to stopping down just as a lens. The limiting resolution goes down, the effective focal length changes and the DOF may or may not change, it is so deep anyway it would be hard to know if there is a measurable difference.

The binocular is just a lump of parts that cannot change its self. Optics theory says that optics is bi-directional, which is true, but light is directional, from the source to the observer. Just like a car going down a highway, when it hits bumps, goes around curves, or through a tunnel that is small enough to remove the top, if after the car passes those points, changing them will have no effect on the car. The same is true of light, going through the bino, the rays react to the diffraction of lenses, clipping in the prisms, etc. until it forms its final image at the exit pupil. No changing of parameters after the exit pupil will affect the exit pupil.

I do not know how this opinion got started, but I have not seen it in any books. The closest thing I have seen is that someone said that when the eye is stopped down then it would be as if looking through a stopped down telescope as far as resolution, unless the difference is made up by magnification. I don’t know but the only place I seem to be able to find this idea is in opinion forums.

I have done a lot of testing over the past several years, taking various optics and measuring resolution, placing an aperture stop in front and stopping the exit pupil down to 2.5 mm, then removing the aperture stop and moving it to the exit pupil and setting the iris at 2.5 mm. The results to the eye are the same as far as resolution, but with an exit pupil stop the binocular is operating at full aperture, only the eye is stopped down. The resolution for the aperture stop and exit pupil stop is the same at the eye.

I could go on for pages and pages about things I have tried to prove the eye stops down a bino and they all failed miserably.

PS: Forgot, a lot of this was discussed in the thread about wasted exit pupil and another thread about larger bins in general.

 

[typo]

Gijs,

I'm not sure I have all the answers to all the points you make. The figures Ron and I are referring to are arcseconds per line pair and the theoretical resolutions calculations are the Dawes limit of 116/lens diameter in millimetres.

These are not point sources under consideration but either a letter as in a Snellen chart or line patterns as in the USAF 1951 chart or others for MTF. The figure you suggest for a cone size of 1/3 seconds of arc would indicate a discrimination level of double that. I don't know for sure exactly how it works but because the cones are in a mosaic pattern potential resolution for lines might half that value or better.

I've puzzled over CA in the eye and haven't found an answer that my little brain understands yet. Obviously it is there in the retinal image but we are not aware of it, just as we are not aware that the image is upside down. The best explanation I can comprehend is that there is a remapping process in the visual cortex, but there are chunks of processing on the way there that I just don't understand.

Though I converted Snellen chart values to arcseconds/line pair, those are acuity values I gleaned from mostly scientific studies, or estimated myself from a line chart.

David

 

[Surveyor]

David;

You may find this of interest since you mentioned you may be a candidate in the future.

About a year ago I had cataract surgery and both lenses were replaced with 6 mm plastic (?) IOL’s. If Dawes or Raleigh holds, that would suggest a limiting resolution of about 20-25”. This is far better than my acuity, which typically runs 100-110” on a good day.

What is interesting, my visual acuity did not change that much going from my past acuity (before the cataracts had a big effect on my vision) to what it is now, which, to me, suggests the natural eye lens is about as good as a modern synthetic lens.

 

[ronh]

RonE,
Thanks for that, I'll try to understand it.
RonH

 

[[email protected]]

RonE,
Thanks for that, I'll try to understand it.
RonH

I called Cameraland about Swarovski Habicht's 8x30's and they said they haven't sold a pair in fifteen years! So they are definitely NOT a popular seller! HaHa! They said they call Swarovski and Swarovski has to make them. I can hear Swarovski when they get an order for the Habicht's " Oh it must be another one of those stupid birder's". Like custom order. Definitely not mainstream.