Bioculars with diverging field of view (1 Viewer)

[Omid]

I am wondering why there aren't any binoculars with diverging fields of view. When the two barrels are parallel, the field of view at long distances is practically the same as the field of view of a single barrel.

With reference to the first attached figure, d is the distance between the center of field of view of left and right barrels. r is the field radius. For roof prism binoculars collimated properly, d is approximately 6.5 cm (the interpupilary distance) and r could be about 55m at 1000m (assuming a 10X binoculars with 110m real field of view at 1000m). The total horizontal field of view for both eyes is d+2r which is practically 2r since d is negligible.

If we make the barrels divergent by a small amount, we can increase d significantly while still maintaining some overlap between left and right fields to make stereo vision possible. This is shown in the second attached figure.

I wonder why there are no binoculars that have this feature. Maybe there have been examples of this kind of binoculars for military and marine use but I could not find any. Has anyone in the forum seen binoculars with diverging fields of view? :h?:

 

[OPTIC_NUT]

The stereo effect is no good where they don't overlap,
but far worse, your eyes can fail to sync the views and
there are double images and splitting headaches.
No fun.

The whole idea of two barrels isn't to cover more ground,
it's to provide two near-identical pictures so the noise and
image-processing in the brain improve the experience.
Your eyes and cortex aren't built for looking at things
pigeon-toed without binocs, so they aren't happy about it
with binocs.

 

[Binastro]

I have several binoculars with divergent fields of view. They are mainly cheap binoculars, which may be collimated more or less for me, but where the two fields or two circles are quite widely different.
The field of view horizontally is larger than normal, but these binoculars are not pleasant to use.

For instance, the 6×18, 7 day shop, waterproof binoculars cost about 7 pounds each. I ended up with about 30 of these. 10 were in good collimation and had good star images, 10 were acceptable and 10 were not. As they are independent eyepiece focusing, the sensible thing to do would have been to make the 10 poor ones into 20 monoculars, which would have been tiny and go in a shirt pocket easily and cost £3.50 each. As it is, several of these binoculars were given as presents, and are still being used. They really do seem to be waterproof and the binoculars are very small and very useful to carry. A pilot friend regularly carries them and uses them for spotting through the aircraft window.

Many of these binoculars were collimated but had widely different circles, which gave much wider horizontal field of view. The reason is that the mechanical axis and the optical axis differ considerably. The technician made them more or less collimated, but with total disregard for two overlapping circles.

In addition, I sometimes deliberately set the IPD slightly wrong on good binoculars to get an increased horizontal field of view.
High-class binoculars usually have perfect overlapping fields of view and perfect collimation.

A much easier way to get wide fields of view is to design it in the binoculars, using widefield eyepieces.
I really do feel the loss of the extra wide-angle older binoculars. Many modern binoculars claim to be extra wide field or Ultra wide field and they are not.

The rather interesting Fujinon 5×21 small binocular is called Ultra wide field at 9.4°. It gives good views and a bright image, but the apparent field of view is certainly not Ultra wide field.

 

[Omid]

The whole idea of two barrels isn't to cover more ground,
it's to provide two near-identical pictures so the noise and
image-processing in the brain improve the experience.
Your eyes and cortex aren't built for looking at things
pigeon-toed without binocs, so they aren't happy about it
with binocs.

Thank you for your comment. The human eyes' filed of view do not "fully" overlap though. There is a large overlap in the center of field of view (about 140 degrees) and then there is the peripheral vision area (about 50 degrees) which dos not contribute to stereo vision. My suggestion was to make binocular's field of view somehow mimic the eyes' natural field of view (?)

 

[Omid]

I sometimes deliberately set the IPD slightly wrong on good binoculars to get an increased horizontal field of view.
High-class binoculars usually have perfect overlapping fields of view and perfect collimation.

I do the very same thing sometimes! It works best with binoculars having large exit pupils (e.g. 8x50). I know that high quality binoculars are perfectly collimated to be parallel. My question is is this necessary in the horizontal direction? What technical issue prevents us from making binoculars slightly divergent to increase horizontal field of view say by 20 to 30%?

A much easier way to get wide fields of view is to design it in the binoculars, using widefield eyepieces.

It is easier conceptually but not so easy in practice. Look, for example, at Zeiss 8X42 SF trying to make the FOV just a couple degrees more than the completion. Making truly wide-field eyepieces require large and heavy optical elements not suitable for binoculars.

 

[Binastro]

. Hi Omid,
190° apparent field eyepieces. That should be fun.

Several of the 6×18 binoculars had overlaps of 20% to 30%. I don't think you'd like using them, even though the horizontal field is much wider than normal and can be used.

If one is prepared to accept less eye relief then apparent fields of 75°, 80° or more are fully realisable. I just don't know why modern makers miss out on this. Maybe the main reason is they don't like Porro prism binoculars.

 

[WJC]

I do the very same thing sometimes! It works best with binoculars having large exit pupils (e.g. 8x50). I know that high quality binoculars are perfectly collimated to be parallel. My question is is this necessary in the horizontal direction? What technical issue prevents us from making binoculars slightly divergent to increase horizontal field of view say by 20 to 30%?




It is easier conceptually but not so easy in practice. Look, for example, at Zeiss 8X42 SF trying to make the FOV just a couple degrees more than the completion. Making truly wide-field eyepieces require large and heavy optical elements not suitable for binoculars.

Message to self:

Bite tongue, hard, but keep your mouth shut until the bleeding stops and crawl back in your hole. You've already had one post, this month. That's one more than you should have.

 

[NDhunter]

Message to self:

Bite tongue, hard, but keep your mouth shut until the bleeding stops and crawl back in your hole. You've already had one post, this month. That's one more than you should have.

Bill:

Binoculars and their design are not rocket science, and this thread
does not seem to mean much in the realm of things.
If it was of importance it would be well known, and in use.

Your thoughts ?

Jerry

 

[WJC]

Bill:

Binoculars and their design are not rocket science, and this thread
does not seem to mean much in the realm of things.
If it was of importance it would be well known, and in use.

Your thoughts ?

Jerry

Hi Jerry:

Take your fists and hold them 10 or so inches in front of you.

Now, raise your index fingers, making them veer away from each other slightly at the nail. Then, you have the divergent axes being discussed.

Now, move your fists in such a way as to mimic the motions that would occur in opening or closing the IPD. What then, do the new angles of those index fingers say about what just happened to your collimation?

“However BEAUTIFUL the strategy, you should occasionally look at the RESULTS.”—Winston Churchill

But, look at the bright side. We have just created another non-existent problem just begging to be solved. :cat:

Bill

 

[Omid]

Now, move your fists in such a way as to mimic the motions that would occur in opening or closing the IPD. What then, do the new angles of those index fingers say about what just happened to your collimation?

Yes, if the barrels point-of-aim are divergent (or convergent), the angle of divergence (convergence) is reduced when you close the hinge to reduce IPD. In the extreme case, if you could reduce IPD to zero, the barrels would become parallel again.

But, look at the bright side. We have just created another non-existent problem just begging to be solved. :cat:

Bill, lets not jump the gun. The idea of making a pair of binoculars such that individual telescopes have divergent or convergent fields of view is not crazy. If the binoculars are divergent, you get more field of view and potentially a better perception of depth (parallax increases). If the binoculars fields of view are convergent, the binoculars will have reduced parallax and can be used for viewing very close objects. It is not possible to use regular binoculars to view very close objects due to left and right images creating a very large amount of parallax (even when the focusing system is able to focus the object). A binocular with converging fields of view solves this problem.

See the attached image from a Zeiss patent (granted in 1981). The patent explains how such binoculars can be used to view very close objects. It also addresses the variable-IPD problem by designing a special hinge.

My question was (still is) what visual or optical issues might prevent us from making such binoculars? The mechanical issue you mentioned is not a road block.

 

[WJC]

Yes, if the barrels point-of-aim are divergent (or convergent), the angle of divergence (convergence) is reduced when you close the hinge to reduce IPD. In the extreme case, if you could reduce IPD to zero, the barrels would become parallel again.



Bill, lets not jump the gun. The idea of making a pair of binoculars such that individual telescopes have divergent or convergent fields of view is not crazy. If the binoculars are divergent, you get more field of view and potentially a better perception of depth (parallax increases). If the binoculars fields of view are convergent, the binoculars will have reduced parallax and can be used for viewing very close objects. It is not possible to use regular binoculars to view very close objects due to left and right images creating a very large amount of parallax (even when the focusing system is able to focus the object). A binocular with converging fields of view solves this problem.

See the attached image from a Zeiss patent (granted in 1981). The patent explains how such binoculars can be used to view very close objects. It also addresses the variable-IPD problem by designing a special hinge.

My question was (still is) what visual or optical issues might prevent us from making such binoculars? The mechanical issue you mentioned is not a road block.

Omid:

You said: “Bill, lets not jump the gun.”

I humbly submit that bringing a touch of reality into posts which seem, more often than not, to thrive on esoterica is not jumping the gun. I will, however, apologize for getting involved; I have been trying to ween myself of coming here.

Please remember that when you were being ignored in droves concerning your rifle scope idea, I was the first to come to your aid hoping to help start discussions that would be helpful to you. Until I did my research, I didn't realize that you were a for profit research company of one. That being the case, I will offer this one post substantiating my comments and leave you to your devices.

I AM interested in serious research. But, while I mean no offense, I just don't have the time nor inclination to walk down esoteric paths that only serve to help you get your next grant or contract. Noble? Not on your life. I'm just trying to use MY time to make a little money for ME! I got a writing gig this morning from Phi Beta Kappa that will equate to real dollars and not just a warm and fuzzy feeling. That makes more sense to me.

I have now, and have always had, a great respect and appreciation for Zeiss' R&D. However, until they have the power to alter the laws of physics, I will let my comments stand . . . as, being a snotty guy, I am so prone to do.

The drawing is indeed a drawing; I like drawings. However, I see it as being considerably below your potential level of thinkology.

1. An angling of the telescopes as you describe, would cause the eyes to be looking at the bundle from the exit pupil at a skewed angle, causing aberrations, an over-taxing of spatial accommodation, or both—probably both.

2. If the binocular were to be used at other IPDs, conventions would need to be used for adjusting the line of sight in the Y axis, if the instrument were to be used by those having a considerably different IPD. I didn't see this in the drawing. Finally:

3. You say you would get a greater depth perception with such an instrument. I say that ANY greater depth perception would be negligible owing to the minuscule increased separation of the objectives, and would most certainly be more than countered by other negative considerations of manufacture and use.

Having said that, I will drop back out of sight and leave you to mine data from others. :cat:

“The problems we face cannot be solved with the same level of thinking we possessed when we created them.”--Albert Einstein

Cheers,

Bill

 

[OPTIC_NUT]

Just the memory of misaligned barrels hurts me!


There is one reason for non-parallel views: close-up work,
like for dentists, surgeons, and circuit-workers.
In that case, your eyes are only comfortable at one distance,
where the target is at the same place in the left and right field.

 

[Binastro]

I don't know what errors were introduced with the bad examples of the 6×18 yellow waterproof binoculars mentioned above.
When the fields overlapped by perhaps 20%, the horizontal field was indeed much larger than normal, but the experience of trying to view through such a binocular is very strange and tiring. I doubt whether I would use such a binocular for as much as 60 seconds without wanting to chuck it in the dustbin.
I did note that even with the worst examples, using each half as a monocular was a quite reasonable idea, as the images were very acceptable in each half, although the star images were sometimes astigmatic, but this error was not noticed in terrestrial viewing.

With regard to fairly good binoculars, which are generally in good collimation, and may have the two fields overlapping by perhaps 1% or 2%, in normal use this is not noticed. However, when I measure fields I do it using stars with accurately known separations. Here it is easy to realise that using both barrels normally, the horizontal field, where the displacement usually occurs, is measurably wider than the vertical field.
So I take the precaution of measuring the field using, say, the right eye viewing through both the left and right barrel, and then the left eye using both the left and right barrel, so I can get a real determination of what the accurate field size is. But because of the slight differences in the position of each eye it can be difficult to get a unique field size.

But in normal use such a binocular does provide a slightly wider field using both eyes, where the circles don't perfectly match. I found that generally with top quality binoculars it is really not possible to see any measurable overlap difference, although it might exist, perhaps 0.1% at a guess. As I am measuring star separations there is no parallax involved, and most of my viewing anyway is at a distance and not close-up.

The Pentax Papilio takes care of close-up views where the two optics start inclining towards each other as you move very close.

 

[OPTIC_NUT]

"
When the fields overlapped by perhaps 20%, the horizontal field was indeed much larger than normal, but the experience of trying to view through such a binocular is very strange and tiring. I doubt whether I would use such a binocular for as much as 60 seconds without wanting to chuck it in the dustbin.
"
And....
Worth noting for those who try to use regular Porros under 9 feet or Roofs under ~6 feet.
There is pain and peril if your fields don't mesh!
Just because it focuses close doesn't mean you should.
Closer for reverse Porros, of course, and Papilios.

 

[Omid]

An angling of the telescopes as you describe, would cause the eyes to be looking at the bundle from the exit pupil at a skewed angle, causing aberrations, an over-taxing of spatial accommodation, or both—probably both.

Hi Bill, You are right and this might be an issue. The brain needs to fuse the partially overlapping images produced by divergent fields of the binoculars and this might cause headache. Thank you for taking time and sharing your thoughts. I wish you good luck with finishing and publishing your book! B

There is one reason for non-parallel views: close-up work, like for dentists, surgeons, and circuit-workers. In that case, your eyes are only comfortable at one distance, where the target is at the same place in the left and right field.

Yes, very true. The "working distance" of converging binoculars will be limited. But, nonetheless, such binoculars exist and they are useful too. This proves that the barrels of a binocular need not always be parallel (in the horizontal direction)!

The Pentax Papilio takes care of close-up views where the two optics start inclining towards each other as you move very close.

These little binoculars are very interesting! I haven't seen one myself but looks like, as you said, they work by decentring (shifting) the objective lenses. This bends the field of view and makes the binoculars look at a converging angle. I am familiar with a patent granted to Minolta that suggests this solution for close-focus binoculars. It might be same mechanism used in Papillo.

 

[WJC]

Omid Wrote: Hi Bill, You are right and this might be an issue. The brain needs to fuse the partially overlapping images produced by divergent fields of the binoculars and this might cause headache. Thank you for taking time and sharing your thoughts. I wish you good luck with finishing and publishing your book!

The book is being edited in Holland, right now. The battle will not be over even when I get it back; I have to go through it, again, to drop in the photos and drawings. I really don't want to go print on demand. On the other hand, I don't want some publisher who doesn't know my audience or impetus turning the book into what it is not--and was never conceived to be.

That Phi Beta Kappa piece I mentioned is to go into their American Scholar magazine. I can write eggheadese. But, I prefer not too. I'm just following the money trail. Since the economy collapsed, that trail is getting very narrow for me.

Cheers,

Bill

 

[Alexis Powell]

...These little binoculars are very interesting! I haven't seen one myself but looks like, as you said, they work by decentring (shifting) the objective lenses. This bends the field of view and makes the binoculars look at a converging angle. I am familiar with a patent granted to Minolta that suggests this solution for close-focus binoculars. It might be same mechanism used in Papillo.

I don't think the Papilio shifts the lenses to a converging angle. The lenses "converge" by moving closer together when focusing closely, but I think they remain aligned and do not angle inwards.

--AP

 

[WJC]

I don't think the Papilio shifts the lenses to a converging angle. The lenses "converge" by moving closer together when focusing closely, but I think they remain aligned and do not angle inwards.

--AP

. . . That is why you get such a massive overlapping of fields--that some complain so much about--when focusing down to view that caterpillar. Your IMAGE is clear but the FIELDS stink; you can't have it both ways in THIS life.

So, which are you interested in; your supposed TARGET or the non-essential overlapping of fields that come with crossing your eyes to focus at 19 inches?

As an aside: I have to wonder why folks, who indicate they want to learn, come to sites like BF and CN to debate stuff like this, when millions of words are just a click away on Google. Many of the articles having been written by leaders in the field of optical engineering?

But then, life is full of such quandaries. :cat:

Bill

 

[NDhunter]

Yes, if the barrels point-of-aim are divergent (or convergent), the angle of divergence (convergence) is reduced when you close the hinge to reduce IPD. In the extreme case, if you could reduce IPD to zero, the barrels would become parallel again.



Bill, lets not jump the gun. The idea of making a pair of binoculars such that individual telescopes have divergent or convergent fields of view is not crazy. If the binoculars are divergent, you get more field of view and potentially a better perception of depth (parallax increases). If the binoculars fields of view are convergent, the binoculars will have reduced parallax and can be used for viewing very close objects. It is not possible to use regular binoculars to view very close objects due to left and right images creating a very large amount of parallax (even when the focusing system is able to focus the object). A binocular with converging fields of view solves this problem.

See the attached image from a Zeiss patent (granted in 1981). The patent explains how such binoculars can be used to view very close objects. It also addresses the variable-IPD problem by designing a special hinge.

My question was (still is) what visual or optical issues might prevent us from making such binoculars? The mechanical issue you mentioned is not a road block.

Omid:

Here is an older binocular that may have been ahead of its time, it is
a simple Wollensak Biascope from back in the 20's or so.

If you look closely it has a rotary focus, and has the provision to adjust the axis entirely, there is another set of top screw holes, and so you could cant the barrels to offer the effect you are describing. It would require some modifications as needed, but does give you some idea of how this may
work.

By the way, these are out of collimation, and now I need to ask Bill
if I could have some help with that ?

I would offer this up as a donor if needed.

Jerry

 

[WJC]

Omid:

Here is an older binocular that may have been ahead of its time, it is
a simple Wollensak Biascope from back in the 20's or so.

If you look closely it has a rotary focus, and has the provision to adjust the axis entirely, there is another set of top screw holes, and so you could cant the barrels to offer the effect you are describing. It would require some modifications as needed, but does give you some idea of how this may
work.

By the way, these are out of collimation, and now I need to ask Bill
if I could have some help with that ?

I would offer this up as a donor if needed.

Jerry

Hi Jerry:

I no longer have the wherewithal, and my guns have been on the nail since 2013 and from Captain's since 2008. Cory's your man. He's honest and skillful; that's a great combination.

Those who can, do; those who can't, teach; those too old and stupid, just write about it, try to help younger guys with their books, and try to remember the "good old days." Give Cory a call.

Cheers,

Bill