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New Horizons II (2 Viewers)

It is not as you say. 3D graphics can create all the necessary appearance of the various focus planes and thus give the effect of depth, as naturally happens in film photography (optical shooting).

Really?! Could you please explain how 3D television or 3D cinema (or 3D headsets that use two small LCD screens behind a Fresnel eyepiece) can create multiple focus planes for all the object presented in the scene?


Alexis Powell said:
Can't most people adapt to such issues, given a bit of experience using the technology?

It is probably possible to get used to it but it certainly is not desirable. This is somewhat like experiencing jet lag. You would get used to it if you stay in the new location long enough but once you return home you have a new problem: getting used to the previous normal.

Another aspect is that the most likely application of 3D technology -as is being presented now- is in the entertainment industry. Most people learn after one trial that they don't want to pay to get headaches or sit next to their date wearing goofy glasses.

A third aspect -which just occurred to me today - is that it might be that when it comes to art and aesthetics, we humans might enjoy 2D art more than 3D. Stereoscopic vision is more of a "utility" in human life providing extremely valuable capabilities such as tool making and hunting. But factual accuracy is not something we seek in art and entertainment. 3D art has existed in the form of sculpture for thousands of years but it never replaced painting. A 3D representation of you is certainly more accurate but would you prefer to see a beautiful portrait of yourself or a sculpture? I am not a philosopher of art but this certainly is an interesting angle to consider.
 
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Really?! Could you please explain how 3D television or 3D cinema or 3D headsets that use two small LCD screens behind a Fresnel eyepiece create a deferent focus plane for each object presented in the scene?
Rhetorical question?
The photograph of the film is two-dimensional, but it is possible to see the depth. Logically, if the focus of the shot was centered on the subject's eyes, the panoramic background behind it will be blurred and nobody will be able to focus on it.

What do you mean by this sentence?
...none of them can create an image whose "virtual objects" require different focusing accommodation in a manner that is consistent with their parallax.
Parallax has nothing to do with it. And anyway, what you are referring to, is a holographic image.

https://youtu.be/H8JZO3mce7o

The cinema, TV and all flat monitor, will only show 2D images with 3D effect. Not holographic images.
Are you kidding or don't you understand the difference?
 
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Hi Rico,

Yes, there is certainly some misunderstanding. Please note that I am not talking about Volumetric Displays. I am talking about Stereoscopic Displays such as those used in 3D cinema, 3D TV and Virtual Reality (VR) headsets. A stereoscopic display produces two images one for left and one for the right eye. More precisely, I am referring to the phenomenon called "Vergence-Accommodation Conflict" in stereoscopic displays. You could Google this term and you might find better and more extensive explanations. Here is a good paper on this subject:

https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf

I hope this clarifies the subject for you.

Sincerely,
-Omid
 
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But this is only a matter of helmeted virtual reality (HMD). And certainly not of 3D cinema or 3D TV, where the observation distances are much greater than 10cm.

http://i.imgur.com/g7isk3c.png


The drawing below is a visual test on three-dimensionality (in stereopsis). Converge the eyes until the two images overlap in a central third, in which you will see the 3D sum and the scene developed in depth.
 

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I have previously discussed two user-experience issues with binoculars:

a) providing exact same field of view to two eyes
b) vergence-accommodation conflict

But these are not the only issues with binoculars. There are a few more: Human eyes are most comfortable looking at an image that appears to be about 100cm away (not at infinity as it is commonly assumed in optical design). In ergonomics, the "resting point of vergence (RPV) is defined as the point on which the eyes converge when relaxed. Humans have evolved to gaze farther off when looking up or straight than down. This is because, when outside, most of the objects higher up are farther away than those on the ground. The horizontal RPV averages 116cm. Looking upward (30 degree angle) increases it to about 135 cm, while looking downwards (-30 degree angle) the RPV decreases to 89cm. These are average values measured by researchers in the field of visual ergonomics.

Similarly, there is a resting point of accommodation, i.e. a natural state for eyes focus. This parameter is also known as the dark or tonic focus. The important point is that this is not infinity as commonly thought. It averages about 80cm.

These ergonomic factors are not considered in the design of binoculars. All hand-held binoculars are optimized for use by a non-existing creature whose eyes have parallel lines of sight and a natural focus point located at infinity.
 
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...... Another aspect is that the most likely application of 3D technology -as is being presented now- is in the entertainment industry. Most people learn after one trial that they don't want to pay to get headaches or sit next to their date wearing goofy glasses......
.
Omid, you seem to have missed my post. Here it is again for your benefit. :t:

Ah Omid - so this is where you hang out when you are not deliberately spamming my thread. I have an LG 4K LED TV and it displays 3D Blueray DVD's fantastically just by merely wearing passive 3D glasses. So real is the effect that you are ducking and weaving at objects coming out of the screen at you (then again I have the whole setup placed at the right distances and viewing angles).

Why haven't you mentioned zoom binoculars yet? :cat: (I know you have a LOT of experience with variable magnification riflescopes [fantastic as a lightweight nature observation device!] - are these all parfocal devices?). What would be involved in designing a satisfactory zoom binocular? (one suitable for eyeglass wearers - 18mm+ ER, with a 70° AFOV - even though I see you have earlier dismissed the importance of a wide field - it's actually very much desired by BIRDERS). :eat:

I disagree that someone would not want to "sit next to their date wearing goofy glasses" of the type that I am referring to ...... unless of course you think that Chris Isaak is somehow uncool :cool: :eat:





Chosun :gh:
 
In theory, adding zoom to binoculars seems a logical improvement but in practice this will lead to multiple complications:

a) The images from the left barrel and the right barrel must enlarge and shrink in perfect coordination. Any missmatch between left and right magnifications will cause visual discomfort.

b) There isn't much room to implement a zoom system (a moving lens or lens group) in binoculars. This is due to the use of prismatic erectors. It is much easier to implemenmt zoom in riflescopes where the erector system comprises a pair of doublet lenses. In these instruments, the errector system doubles as the zoom system.

c) Having two knobs to operate will hinder usability: You need to manipulate both zoom and focus. It will also be necessary to "tweak the focus" everytime you change zoom. This leads to a very poor user experince. (This problem exists in spotting scopes too).

d) Any slight error in the lateral position of the moving zoom lenses will result in a loss of colimation. This problem does not cause an issue in spotting scopes but is known to cause problems in riflescope that have their reticle (cross-hairs) in the second focal plane.

For these reasons, we are unlikley to see any zoom binoculrs among the premium models. The Leica Duvids will likley be the last attempt at providing zoom in premium binoculars.
 
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Happy Friday!

I came across this outstanding paper by Mr. David Williamson and I thought it is worth mentioning here. Mr. Williamson wrote this paper when he was with Ernst Leitz (ELCAN) in Ontario, Canada not too far from Toronto where I went to school. He seems to be retired in Arizona now (again not too far from where I am!)


The paper begins with the following statements:

"One of the best kept secrets of the universe is how the human eye works. Even today,
despite the tremendous efforts of researchers everywhere, much of the process remains a
mystery.

The mystery of the human eye extends to optical instruments used with it. Although the
most classical area of geometrical optics, the design of such instruments retains an
element of 'artistic license 1 when compared with more recent optics that interface with
linear man-made systems.

In a sense, the eye is very forgiving of an optical system placed in front of it.
Although it will tolerate a certain amount of aberrational abuse for short periods of time,
it remains the optical designer's responsibility to reduce the strain imposed on the eye by
treating it as kindly as possible within constraints imposed by size, weight and cost."


and concludes with the following observation:

"Perhaps the day is not too far away when an optical designer can seriously contemplate a
system using a gradient-index, variable-power, aspheric lens with continuously variable
auto-iris, auto-focus, a variable density array of detectors on a spherical image surface
immersed in liquid, and sophisticated focal surface image processing. The mystery remains of
how the eye was designed and made that way so long ago".


;)
 

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In theory, adding zoom to binoculars seems a logical improvement but in practice this will lead to multiple complications:

a) The images from the left barrel and the right barrel must enlarge and shrink in perfect coordination. Any missmatch between left and right magnifications will cause visual discomfort.

b) There isn't much room to implement a zoom system (a moving lens or lens group) in binoculars. This is due to the use of prismatic erectors. It is much easier to implemenmt zoom in riflescopes where the erector system comprises a pair of doublet lenses. In these instruments, the errector system doubles as the zoom system.

c) Having two knobs to operate will hinder usability: You need to manipulate both zoom and focus. It will also be necessary to "tweak the focus" everytime you change zoom. This leads to a very poor user experince. (This problem exists in spotting scopes too).

d) Any slight error in the lateral position of the moving zoom lenses will result in a loss of colimation. This problem does not cause an issue in spotting scopes but is known to cause problems in riflescope that have their reticle (cross-hairs) in the second focal plane.

For these reasons, we are unlikley to see any zoom binoculrs among the premium models. The Leica Duvids will likley be the last attempt at providing zoom in premium binoculars.

200117

Hi, Omid,

Friends don’t let friends use ZOOM binoculars.

I number of times, people, with ZERO optical experience, have taken it upon themselves to corroborate something I’ve said. I never learned to appreciate that and I hope you don’t feel I am doing the same. But, after 21 years of explaining this several times a week, I feel pretty strongly about the issue and thought the graphics might help.

Bill
 

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Additional Information - Prismatic Monoculars prior to 1894

I recently came across more information and images about early prismatic monoculars, at the website Monokulare/ Monoculars
It expands on the information in posts #28 and 30, and may be of interest to those historically inclined

Start at: http://www.monocular.info/history/monohistory.htm and follow the screen flow
It includes:
- the 2 types of monoculars that Ignazio Porro commissioned Hofmann to make (i.e. Porro Type I and Type II)
- a photo of a model by Sammlung of Zurich (no date)
- Steinhall Porro Type II prototype ca.1855?
- Busch Porro Type I from 1865
- Abbe’s Porro Type I prototype of 1873

Some additional Googling using ‘Porro prism monocular telescope’ and then going to the images option, found a number of Hofmann Porro Type I models with serial numbers from 221 to 600
(I would presume that the numbering included other non-prismatic telescopes)
See two images of #330 from the Hutchinson Scott auction site: https://www.hutchinsonscott.co.uk/e...nd-original-leather-case-12cm-high/lot_17_306

And for comparison see the images of the distinctly different Hofmann Porro Type II from the Monoculars website


John
 

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Hello all (and thank you John for posting your always-interesting findings here)

I was attending SHOT Show in Las Vegas last week. I visited Zeiss, Leica, Swarovski, Fujinon and a few other premium optics manufacturers. At Leica booth, I had a productive conversation with Messrs. Mogwitz and Albrecht regarding one of my riflescope concepts. At other booths, I simply browsed the products and said hello to those staff that I knew.

I noticed that Nikon had no booth at this year's convention. This probably has to do with their recent decision to exit the hunting market. I heard from my well-connected friends that another premium optics company is contemplating a same move.

Another observation was the proliferation of Asian OEM companies who are now attending the show under their own names and are offering to sell products directly to US shops and retailers. There were at least 10 such companies. There also was a "German" optics brand with a booth in the Germany's pavilion which was staffed entirely by Asian persons! It is not hard to guess where this company's products really come from.

So, all is well. The industry is following its known course..
 
Hello all (and thank you John for posting your always-interesting findings here)

I was attending SHOT Show in Las Vegas last week. I visited Zeiss, Leica, Swarovski, Fujinon and a few other premium optics manufacturers. At Leica booth, I had a productive conversation with Messrs. Mogwitz and Albrecht regarding one of my riflescope concepts. At other booths, I simply browsed the products and said hello to those staff that I knew.

I noticed that Nikon had no booth at this year's convention. This probably has to do with their recent decision to exit the hunting market. I heard from my well-connected friends that another premium optics company is contemplating a same move.

Another observation was the proliferation of Asian OEM companies who are now attending the show under their own names and are offering to sell products directly to US shops and retailers. There were at least 10 such companies. There also was a "German" optics brand with a booth in the Germany's pavilion which was staffed entirely by Asian persons! It is not hard to guess where this company's products really come from.

So, all is well. The industry is following its known course..




The link below is from the current Nikon Website.


https://www.nikonsportoptics.com/en/nikon-products/hunting-and-shooting/index.page

Bob
 
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In theory, adding zoom to binoculars seems a logical improvement but in practice this will lead to multiple complications:

a) The images from the left barrel and the right barrel must enlarge and shrink in perfect coordination. Any missmatch between left and right magnifications will cause visual discomfort.

b) There isn't much room to implement a zoom system (a moving lens or lens group) in binoculars. This is due to the use of prismatic erectors. It is much easier to implemenmt zoom in riflescopes where the erector system comprises a pair of doublet lenses. In these instruments, the errector system doubles as the zoom system.

c) Having two knobs to operate will hinder usability: You need to manipulate both zoom and focus. It will also be necessary to "tweak the focus" everytime you change zoom. This leads to a very poor user experince. (This problem exists in spotting scopes too).

d) Any slight error in the lateral position of the moving zoom lenses will result in a loss of colimation. This problem does not cause an issue in spotting scopes but is known to cause problems in riflescope that have their reticle (cross-hairs) in the second focal plane.

For these reasons, we are unlikley to see any zoom binoculrs among the premium models. The Leica Duvids will likley be the last attempt at providing zoom in premium binoculars.

The zoom feature is easy to add, provided it is on only 1 optical train.
So a zoom binocular would have a Harpia like front end with a Swaro BTX binoviewer attached. It does sacrifice the 3D effect of conventional 2 train binoculars, but that may be an acceptable tradeoff.
I do not know whether anyone has offered such a rig commercially, but certainly people who use cameras such as the Nikon P1000 get an approximation of the effect.
 
The provision of synchronized focusing individual tubes is analogous to eliminating focusing hysteresis - even though zoom (or dual, or even tri-power) is compounding the issue - surely with some advanced engineering the problems are not insurmountable ?




Chosun :gh:
 
Stiles–Crawford effect

In the past few weeks, I have been reading about an interesting physiological effect called Stiles–Crawford effect of the first kind. This effect relates to how the human eye perceives the brightness of a pencil of light when the pencil enters the eye at the center of the pupil vs near the edges of the pupil. The confirmed observation is that a pencil of light entering away from the center of the eye pupil creates less perceived brightness. You can read more details in the attached paper which provides an excellent introduction to this topic.

The Stiles–Crawford effect has some serious implications with regards to measuring the perceived brightness of various binocular configurations: A first implication is that increasing the diameter of the exit pupil does not lead to a proportional increase in the brightness of the retinal image. The gain in brightness will decrease as the exit pupil widens.

One thing that I am still not clear is how the Stiles–Crawford effect is measured for photopic vision? The papers often say that this effect is most prominent when cones are used as receptors (implying photopic vision in sufficient light) and then show plots for eye pupils as wide as 8mm! The eye pupil doesn't naturally open to such diameters under sufficient light so my guess is the researches use special drugs to open up the pupil of their subjects while they are seated in a dark room. Then, they illuminate various parts of their eye pupils using narrow pencils of light of sufficient intensity (?)
 

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The zoom feature is easy to add, provided it is on only 1 optical train.
So a zoom binocular would have a Harpia like front end with a Swaro BTX binoviewer attached. It does sacrifice the 3D effect of conventional 2 train binoculars, but that may be an acceptable tradeoff.
I do not know whether anyone has offered such a rig commercially, but certainly people who use cameras such as the Nikon P1000 get an approximation of the effect.

I've seen a working prototype of a single lens 3d imaging system for motion picture cameras. It involves a matrix of pinholes distributed across the field, that is then split into 2 coherent images yielding a stereo pair. Software and digital imagery are required. I agree most of the technology exists in one form or another. I expect the product will come from the camera manufacturers, not the high end optical companies, though one of them may provide the lens system for it.

-Bill
 
Stiles-Crawford Effect - Continued

On further research, I found a paper published by W. S. Stiles in the Proceedings of the Royal Society in March 1939. The paper is titled "The directional sensitivity of the Retina and the spectral sensitivities of the rods and cones". It is a comprehensive paper covering more than 40 pages.

This paper confirms what I had guessed in my previous post: the Stiles-Crawford effect has been measured for test subjects seated in a dark room to allow their eyes to adapt to darkness. Drugs were also used (when necessary) to dilate their eye pupils.

This 1939 paper has extremely interesting results on the relative response of the dark-adapted human eye to light pencils entering near the edges of the pupil. It shows that the fovea is far less responsive to light beams entering away from the center of the pupil.

The Stiles-Crawford effect explains why a 10X50 binocular might show a point source (such as a star against dark background) brighter than a 7X50 binocular. The same amount of light arrives at both objectives, but -assuming same optical quality- the 10X50 binocular feeds that same gathered light to the eye via a smaller 5mm exit beam compared to the 7mm beam produced by the 7X50 binocular. The narrower beam produces more "perceived brightness" as per Stiles-Crawford effect since it is more concentrated near the center of the pupil.

The Stiles-Crawford effect is likely the true explanation for the observed phenomenon that given equal objective sizes, binoculars with higher magnification might produce brighter images in twilight. (twilight factor de-mystified ;) )

Stiles and Crawford's remarkable discovery has other interesting consequences pertaining to binoculars. I'll cover them later.

-Omid
 

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Found some of his original notebooks many years back. The trouble with all these “observer” measurements is that it involves locking people into darkened rooms for long periods looking at very dim coloured flashing lights... none of them are based on that many observers and so results don’t necessarily provide a good coverage of variability in the wider population. very interesting

Peter
 
Stiles-Crawford Effect - Continued

The Stiles-Crawford effect is a significant sicentific discovery and has been verified many times by various researchers since its discovery nearly 90 years ago. The observation arose out of a failed attempt by W.S. Stiles and B.H. Crawford to measure the areas of the entrance pupils of their experimental subjects as part of a research program which addressed problems of glare, e.g. disabeling glare produced by auotomobil head-lights. Their research was conducted at the National Physical Laboratory (NPL) in England.

These two fine scientists properly deduced the reason for the failure of their experimental design, and they effectively described and defined a new feature of the human visual system. (The 1939 paper I sited in my previous post proves the 3-color receptor system of the eye simply by making statistical threshold detection observations!! Truly brilliant!) In time, it was realized that this phenomenon was associated in large measure with the waveguide/fiber-optics properties of photoreceptors, and that this was a feature shared by virtually all vertebrate species.

I have not seen Stiles-Crawford effect being discussed or considered in relation with low-light performance of binoculars. The excellent paper by Holger (J. Opt. Soc. of America, 2015) doesn't mention this effect but uses the work of a German scientist named Max Berek to explain twilight performance. Looks like I have to write a complementary paper myself! It would be interesting to see if/how factoring in the Stiles-Crawford effect could explain twilight performance of binoculars in a manner compatible with these other works cited by Holger.

-Omid
 

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