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Old Wednesday 18th October 2017, 15:35   #51
Omid
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Omid,

It took me a while to find this book on my shelves "Visual Coding and Adaptability" by Charles S. Harris. The chapter by Richard Held starting on pg. 69 goes into many of the optical and psychological effects created by prism viewing, as shown in the attachment. (rotate the image, ccw) It's inexpensive enough to add to your collection, and I'm sure you will be interested.

Ed
Hi Ed,

Thank you for the tip! There is another book (which I think you introduced to me in 2015) titled "Binocular Vision, Foundations and Applications" by R. W. Reading. It has the same drawing shown on page 288. Reading's book and the one you mentioned both cite a 1952 paper by K. N. Ogle called "Distortion of the image by ophthalmic prisms". Do you have access to this original paper by any chance?

I understand that the distortions caused by the prisms (color separation, astigmatism and some field curvature) need to be considered and mitigated. But this is no more difficult than doing same with distortions caused by lenses or other optical elements used in binoculars. The color separation can be easily solved by using an achromatic prism. Astigmatism and field curvature can be reduced by slightly tilting the prism or by using a prism in reverse orientation at the ocular side of the binoculars! As you and Bill mentioned, we can also rely upon human eye/brain adaptation.

Another note: When I suggest positioning prisms in front of the objective, the "bending" required is in the order of just 1 degree. This is far less than the bending used in ophthalmic applications. So, the distortions caused are far less..

Thanks again,
-Omid
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Old Wednesday 18th October 2017, 16:02   #52
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... Even so, that kid Omid is doing a great job in getting patents and making a name for himself. If given his head, he might open new vistas for those who follow. Thomas Edison didn’t fail as many times as people think...
Bill, I appreciate the compliment. It is very kind of you.

On the surface, it seems impossible to make any major improvements in the usability and ergonomics of binoculars. After all, they have been invented more than a century ago and the basic optical structure has remained the same. But this is no reason to stop exploring.. Think about archery. The bow has been invented when humans lived in caves and has been gradually improved until it reached its apex during the middle ages. Then, all of a sudden in 1960s, Mr. H. W. Allen, Jr. living in the American Midwest revolutionized archery with the invention of the compound bow!

I think we can do same to our beloved field of sporting optics. The more I learn about binoculars and human vision, the more I am convinced that there are still possibilities for improvement (not just better coatings and less aberrations etc.) We already have great contrast and resolution in existing binoculars but the way this image is delivered to the human eye might not be ideal. My invention here is just a first [crude] step.

I invite you, Ed, Holger and other members of the forum who have sufficient knowledge of optics to think about improving binoculars. This would be more useful than spending countless hours debating weather Swarovski X model has less color contrast than Leica Y model. Even if we fail, we learn something and we get credit for trying:
"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat. - Theodore Roosevelt April 23, 1910"
Leave your spectator seats and come join me in the arena...


Regards,
-Omid

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Old Wednesday 18th October 2017, 17:34   #53
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Bill, I appreciate the compliment. It is very kind of you.

On the surface, it seems impossible to make any major improvements in the usability and ergonomics of binoculars. After all, they have been invented more than a century ago and the basic optical structure has remained the same. But this is no reason to stop exploring.. Think about archery. The bow has been invented when humans lived in caves and has been gradually improved until it reached its apex during the middle ages. Then, all of a sudden in 1960s, Mr. H. W. Allen, Jr. living in the American Midwest revolutionized archery with the invention of the compound bow!

I think we can do same to our beloved field of sporting optics. The more I learn about binoculars and human vision, the more I am convinced that there are still possibilities for improvement (not just better coatings and less aberrations etc.) We already have great contrast and resolution in existing binoculars but the way this image is delivered to the human eye might not be ideal. My invention here is just a first [crude] step.

I invite you, Ed, Holger and other members of the forum who have sufficient knowledge of optics to think about improving binoculars. This would be more useful than spending countless hours debating weather Swarovski X model has less color contrast than Leica Y model. Even if we fail, we learn something and we get credit for trying:
"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat. - Theodore Roosevelt April 23, 1910"
Leave your spectator seats and come join me in the arena...


Regards,
-Omid

Omid:

Thank you for THANKING me. But, I am only on the side of truth. Ed Huff was in the “arena” when you were pooping green and Holger is there, now. Walk softly, but in a straight line.

I loved your TR quote.

He also said: “Speak softly but carry a big stick.” That WAS great advice.
Today, Bill Cook says: “If your stick is big enough, and the world knows you’ll use it, you don’t have to waste your breath.”

Cheers,

Bill
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Old Friday 20th October 2017, 05:35   #54
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Bill, I appreciate the compliment. It is very kind of you.

I invite you, Ed, Holger and other members of the forum who have sufficient knowledge of optics to think about improving binoculars. This would be more useful than spending countless hours debating weather Swarovski X model has less color contrast than Leica Y model. Even if we fail, we learn something and we get credit for trying:

Regards,
-Omid
how about 10x contact lens, then when you want to have normal vision, you put on a pair of glasses. Not sure about the practicalities or physics behind it, but would be sure coool to have zoom vision in the eyes!
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Old Sunday 22nd October 2017, 15:58   #55
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but would be sure coool to have zoom vision in the eyes!
"zoom vision" is an interesting concept. It is curious that no animal - as far as I know- has zoom vision. There are insects with multiple eyes but there is no creature with zoom vision.

Zoom is also an interesting concept in sports optics: Binoculars could definitely benefit from zoom but since it is very difficult to keep magnification the same in both barrels, very few zoom models have been made.

On the other hand, zoom is very easy to implement in rifle scopes since they use erector lenses instead of prisms. But that's actually not so useful and could be distracting the hunter (if you leave your scope at high zoom, you can't find the target and by the time you figure this out and reduce zoom, the game is gone!) Also, it causes problems with where the reticle should be (first focal plane or second focal plane). The correct solution here is a "dual-sight", one with low power and one with high power. (I have several patented inventions in this field)

Now, one area that zoom is useful and it has also been implemented too is spotting scopes.

-Omid

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Old Wednesday 1st November 2017, 19:41   #56
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Small update. I haven't been able to perform any major tests, only a brief look through my 8x32 in the Scandinavian evening darkness.

I can vouch for the idea as such in that it actually works to place a prism outside one of the objective lenses, with the prism base laterally.
The FOV expands while the compound, binocular FOV decreases so the view looks more like in the comics books.
I can detect the added convergence strain and suspect that extended use would cause fatigue with some individuals. I have not yet been able to introduce an ocular-side prism as that would require that I have three hands, so I must either wait for the evolution process to take me there, or find a way to support the binocular so that my two hands can run the prism business.

I used a 1 prism diopter trial lens and a 2 prism diopter. The 1 power moves the image 0.57 degrees (10 m/1000 m) and the 2 power 1,15 degrees (20 m/1000 m).
It is readily noticeable how the convergence seemingly decreases the magnification. This is exactly what happens when using a porro binocular at a finite distance, although now it's there all the time, even at infinite distance.

So how much does this affect the perceived magnification? I'd say it differs between individuals, but for me it looks a lot like changing from 8x to 7x magnification.
With the increased FOV, I'd say that the immediate experience is that I change from a 8x32 with 140 m FOV to a 7x28 with a 150 m FOV.
Nothing extraordinary, really.

I'll be back as soon as I have found a way to introduce the ocular-side prism.
//L
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Old Wednesday 1st November 2017, 21:19   #57
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Hi Lars,
Why does the aperture reduce?
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Old Wednesday 1st November 2017, 22:07   #58
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Hi Lars,
Why does the aperture reduce?
Neither the real magnification nor the exit pupil reduce, but since the perceived magnification is reduced with constant exit pupil, i.e. the brightness is constant, it must translate to a 7x28.
These are only words, a mean to describe what I think would be comparable.

//L
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Old Saturday 4th November 2017, 10:44   #59
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Saturday, and off work so I have had the time to play some more with the prisms.
In the test I used a Meostar 8x32 with a 140 m/1000 m FOV, i.e. a wide-angle binocular.

In front of one of the objectives, a 2 prism diopter trial lens with the base laterally:


At long distance: I watch a distant chimney, turn the binoculars slightly so it's barely outside of the FOV.
Introducing the prism reveals the chimney again, in the most lateral part of the FOV only delivered by one of the barrels. The other barrel's FOV edge floats next to it as a slight indication of the transition to the compound/binocular FOV. A slight reduction of the magnification is perceived as recently described.
There's a nasty colour fringing which may be due to the plain crown glass of the trial lens.

At fairly close distance: The effect is huge, with a significantly reduced overlap of the FOV's and an almond-shaped central part representing the compound FOV. The total FOV is considerably larger than without the prism. It reminds a lot of using a porro at very close distance without adjusting the IPD.
Even here, a slight reduction of the magnification is perceived.
Removing the prism causes massive double-vision for several seconds, indicating a major convergence strain.

Apparently, the 2 prism diopter power is too much for me. Reducing this to the "1" power mitigates the worst undesirable effects, but the increase of the FOV is insignificant at longer distance.

In front of one of the objectives, a 1 prism diopter trial lens with the base medially

At long distance:
Tried with the "2" power but this required more divergence than I'm capable of, and my exophoria is roughly 20 prism diopters of which 3 are corrected in my glasses. Apparently, the vergence of the eyes needed to correct for a horisontal prism is multiplied with the factor of the magnification when placed in front of the objective.
Even I, with my major exophoria, can barely avoid diplopia with the "1" power". A vast majority of people would not accept any divergence.
At fairly close distance: Nothing spectacular to report
At very close distance: A relaxed view with a perceived increase of magnification, similar to the view of a reverse-porro.

Prism between eye and the ocular lens:

Very minor effect with these weak prism powers. I can adapt to the effect regardless of prism base direction, and detect no advantage of either direction compared to not using a prism. People with binocularity problems would be best served with spectacles addressing these.


Discussion:

My objections seem to have been largely correct.

- The advantage of a slightly wider FOV at long distance is compromised by the lack of binocular FOV where the advantage appears: near the edge.
With a wide angle binocular, turning the eyes so far sidewards is uncomfortable anyway. Base-out prisms do increase the total FOV at the expense of the compound FOV.

- The extra convergence needed to adjust for the prism may be favourable for a minority of users when looking at a distance, a minority that is further reduced when it comes to close distance viewing.

- The effect obtained by the prisms imitate that of using porro or reverse-porro binoculars.

However, in the porro case, without the advantage of the wider spacing between the objectives (parallax) which enhances the 3D perception.
A prism cannot yield a better 3D perception; it is not a magic gem that can see around corners. More parallax can at least give a glimpse.

- The base-out prism causes the so-called porro effect: the magnification seems weaker than that of a roof binocular with the same power.

For me, case is closed. Current wide-angle designs, roofs as well as porros, do a better job than diverging FsOV in every respect.
Regarding convergent FsOV: In theory, a roof design with base-in prisms on the objective side would yield a better 3D perception than a reverse-porro, but that's about it.

//L
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Old Sunday 5th November 2017, 07:11   #60
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Very nice report, Lars, and by someone qualified to do it too.

Ed
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Old Sunday 5th November 2017, 08:48   #61
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Very nice report, Lars, and by someone qualified to do it too.

Ed
Thank you Ed! Feeling a bit like a bad guy when Omid invested so much headwork.

Now for another tidbit from the goody bag of optics. The insight struck me that one a lot better way to achieve a laterally extended FOV would be to decenter the eyepiece's field stops laterally.

Just like the prism method, the total FOV would increase at the expense of the compound FOV. However without all the other disadvantages like eye strain/headache/diplopia and seemingly reduced magnification, not to mention the compromised image quality due to chromatic aberration and the need to fine-adjust the prism base direction for IPD.

Like previously mentioned, even a wide-angle binocular's FOV is about 40 degrees narrower than the human FOV, which means that an ordinary binocular's FOV represents a fraction of the human FOV. When moving the eyes within the view, the human FOV follows within the available FOV of the binocular.

This is why divergent FsOV or decentered fieldstops will consume parts of the compound FOV, and that is why wide-angle binoculars, roofs and porros alike, always will be a better way to expand the FOV.

//L
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Old Sunday 5th November 2017, 15:45   #62
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I got better results with the faulty 6x18 yellow waterproof roofs, where it seems the tubes were not mechanically parallel and the operator just aligned the optics to compensate, giving a considerably wider FOV. I don't think I got much headaches, but didn't like them.
I'll see if I can find a faulty one to try again.

I presume that moving field stops laterally would need wide field eyepieces, so what is the point?
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Old Sunday 5th November 2017, 16:38   #63
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I got better results with the faulty 6x18 yellow waterproof roofs, where it seems the tubes were not mechanically parallel and the operator just aligned the optics to compensate, giving a considerably wider FOV. I don't think I got much headaches, but didn't like them.
I'll see if I can find a faulty one to try again.

I presume that moving field stops laterally would need wide field eyepieces, so what is the point?
Yup. No point, but then again a better way to expand the FOV than using prisms. Best way is still using wide field eyepieces.

//L
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Old Tuesday 14th November 2017, 17:39   #64
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Hello Lars,

Thank you very much for taking time and testing various configurations according to my ideas. Your observations actually confirm my own observations and experiments. They show what this technique can achieve and what the challenges are. If I summarize your observations:

a) Diverging the axes of view: You confirmed that when viewing long-distance objects, the horizontal field of view of the binoculars is increased while the "overlap" between the left and right fields of view is no longer 100%. There will be overlap only at the medial portion of the fields of view so stereopsis (3D vision or depth Perception) only happens at this portion. Well, this is perfectly fine and exactly what happens in normal (un-aided) human vision. You focus your gaze at an object directly in front of you and the side of your fields of view don't overlap, they just give situational awareness and detecting motion.

This option is obviously not suited for viewing near objects. The opposite trick (converging the axes of view) is to be used here. Your observations confirm this.

B) Converging the axes of view: Here too you confirmed the validity of the concept: "At very close distance: A relaxed view with a perceived increase of magnification, similar to the view of a reverse-porro". That's exactly what I had claimed: Positioning the prisms in front of the objectives in the converging configuration will allow binocular viewing of very close objects.

Your other observations regarding color fringing, etc are all valid too. But as you noted they can be mitigated. Note also that we can put prisms both in front of the objectives and after the eyepieces. The second prisms can simply cancel out the color fringing and other undesirable effects of the frontal prisms (magnification of the binocular must be considered in choosing prism adopters).

Finally, I have achieved another great goal: I inspired you and a few others here to think outside the box and discover new possibilities in designing binocular instruments. As you discovered for yourself, a similar effect can be produced by laterally shifting the field stop of the binoculars. I had discovered this too and I have pending patents on this variation and several other variations (e.g. binoculars with tilted image planes).

The topic of optimal configuration for binocular vision is still open to exploration. All has not been discovered yet. You are now in the arena! Let's explore further together and if we discover some other interesting configurations, I'll be happy to file for a joint patent application on the the topic.

Thank you very much for your efforts again,
-Omid

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Old Tuesday 14th November 2017, 18:46   #65
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Thank you Omid

Again, I'd like to stress that the power of a prism placed outside of the objectives will be multiplied with the magnification. Hence, a 0,5 prism diopter lens will require 5 diopters of eyeball convergence when used at infinity.
At the same time, the image shift/increase of FOV will be a mere five meters per 1000 m FOV.

On the ocular side, prism powers must be significantly higher to even be detected - to regain eyeball parallelity they must match the magnified anterior prism power.

I disagree with you regarding the usefulness of a decreased medial compound FOV.
If we're dealing with a reasonably wide-angle 65 degree AFOV, every part of the FOV will consist of true binocular vision.
More than that, the "wide AFOV" will still cut away large parts of the human binocular field of view.
Diverging FsOV will further restrict the (already) restricted compound FOV.

And it does not stop there, unfortunately.
When using the naked eyes, the human binocular field of view will follow with the version movements (up, down, left and right and combined vectors allowing oblique gaze directions), albeit with some restrictions caused by the nose and the eyebrows.

At best, binoculars allow the eyes to roam the FOV, maintaining true binocular vision all the way to the field stops. There are undeniably lots of binoculars that will cause blackouts or kidney-beaning even with moderate version movements, but that's another problem.

With a further restricted compound FOV, it requires a more active physical directing of the binoculars since the available eye roaming area within the FOV will be clearly more restricted.

Regards,

Lars
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Old Tuesday 14th November 2017, 19:28   #66
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Thank you Omid

Again, I'd like to stress that the power of a prism placed outside of the objectives will be multiplied with the magnification. Hence, a 0,5 prism diopter lens will require 5 diopters of eyeball convergence when used at infinity.
At the same time, the image shift/increase of FOV will be a mere five meters per 1000 m FOV.

On the ocular side, prism powers must be significantly higher to even be detected - to regain eyeball parallelity they must match the magnified anterior prism power.

I disagree with you regarding the usefulness of a decreased medial compound FOV.
If we're dealing with a reasonably wide-angle 65 degree AFOV, every part of the FOV will consist of true binocular vision.
More than that, the "wide AFOV" will still cut away large parts of the human binocular field of view.
Diverging FsOV will further restrict the (already) restricted compound FOV.

And it does not stop there, unfortunately.
When using the naked eyes, the human binocular field of view will follow with the version movements (up, down, left and right and combined vectors allowing oblique gaze directions), albeit with some restrictions caused by the nose and the eyebrows.

At best, binoculars allow the eyes to roam the FOV, maintaining true binocular vision all the way to the field stops. There are undeniably lots of binoculars that will cause blackouts or kidney-beaning even with moderate version movements, but that's another problem.

With a further restricted compound FOV, it requires a more active physical directing of the binoculars since the available eye roaming area within the FOV will be clearly more restricted.

Regards,

Lars

Hi, Lars:

I’m just looking for your opinion. You may respond to: wjc1111@hotmail.com

Is what Omid is trying to ascertain of any practical value, considering production costs in machining, testing, failure rates, collimation issues, and the seemingly limited market? Or, is he just rearranging deck chairs on Titanic? That great American sage, Jeff Goldblum—in Jurassic Park—said that just because you CAN do something, it doesn’t follow that you SHOULD.

He knows I wish him well. But, there needs to be a production “pay-off” that I have not been able to see—all realities considered.

I’m not poo-pooing—just fact finding.

Bill
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