Category Archives: 3D Motion Picture

Boston Globe, Tom Keane, The curse of 3-D movies, Jan. 2, 2011

Hi Tom,

Your article in today’s Globe where you celebrate your inability to see with stereovision is a fascinating study that I have seen before. For some reason, some people with strabismus believe that they have no disadvantage (and from the standpoint of your article you seem to think you have an advantage) when it comes to how they perceive the world. Nothing could be further from the truth. The ill effects of strabismus have been well documented by noted scientists including Oliver Sacks, Susan Barry, Dominick Maino, Frederick Brock and a host of others. I suggest you Google those names and do some reading. Surprisingly, your “lazy eye” condition might be improved by vision therapy and that might surely change your perception with regards to 3D.

The fact that a motion picture can be seen by an audience in 3D has nothing to do with whether or not the movie is good or bad. However, 3D can most certainly make a movie better as well as worse in the same way digital cameras and projection equipment can make a movie better as well as worse.

Instead of slamming the technology, how about slamming directors and producers for poor implementation of 3D? …And heralding directors and producers for good implementation of 3D? But you indicate you can’t see 3D, so how would you know if the 3D was good or bad?

3D is not a novelty. 3D is the way the majority of the population perceives the world and everyday life. It is one of the ways we distinguish “real” from “referential” imagery. This most certainly, in the hands of a skilled director/producer, can make for amazing motion picture making – and there are many scenes that have been produced in 3D that achieve amazing quality and “realness”.

I’m fine if you want to pan the 3D implementation of a film for having technical problems. However, I don’t see how you would be qualified since you don’t see with stereovision. Indeed, I submit that you are not qualified to write the article you wrote. It would be analogous to a deaf person panning the BSO because the conductor waved his arms without authority. That person might be able to see the string section moving their bows and feel the vibrations of the air around them but I think judging the performance in a widely circulated newspaper would be an overreach.

I encourage you to seek help for your eye alignment condition. A great resource is

Your comment “…2-D versions of the same films are clearer and more engrossing.” is way off the mark for those who can see with stereovision. Nothing could be further from the truth. You do the public a disservice making that statement. Parents need to be encouraged to do everything possible for a child with lazy eye or strabismus as it can lead to a whole host of problems where ADD and learning disability can be misdiagnosed and a child needlessly medicated when all they required was vision therapy.

Seeing with 3D is a very big deal. I encourage you to find out if vision therapy could help you. In the meantime, I suggest you reconsider reviewing anything 3D until you are able to see and judge imagery with binocular disparity (stereopsis).

As to your dismissive tone with regards to Avatar, you really missed what happened there…

Good luck with vision therapy, Tom. I really mean that. I hope you gain stereovision and with it, the ability to write a meaningful article that provides an accurate perspective. Your disability absolutely does not provide you with ANY advantage. In this mindset, you are wrong in my humble opinion (and in the opinion of many others like you who have gained stereovision later in life). It is quite possible that you could overcome your disability through vision therapy. Please check it out.


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Filed under 3D, 3D Motion Picture, stereopsis, stereovision, strabismus, vision therapy

I am presenting a paper at SPIE January 25, 2011 at 5:30 PM Paper 7863-49

SPIE (the International Society for Optical Engineering)  See: is holding a conference on 3D imaging from Jan. 23 – 27 in San Francisco, CA. My paper and presentation: “Human perception considerations for 3D content creation” is about the problem of perception conflicts as they relate to 3D imagery and what to do about them.

I first started thinking about this when I saw an old lenticular photograph of Queen Elizabeth. The photograph could be viewed with stereopsis but the Queen looked like she was dead. Watching the movie Beowulf, while not in 3D, also gave me the creeps as the characters had a dead aspect to them. I noticed some 3D lenticular photographs of people presented with a doll-like character. I then started to notice things in 3D movies that didn’t seem right. When details disappeared into blackness or got blown out to white I noticed an uneasy feeling while looking at that part of the 3D presentation.

Indeed, every time something was presented in 3D that was atypical or not possible to see in the real world, I could detect a feeling of conflict present at some level in my subconsious and I started to manifest a sensitivity to it with regards to recognizing when it was happening.

All of these observations got me thinking about the various mechanisims that we use to see and interpret depth, space and texture. Certainly vergence is the primary mechanism, but as I became more aware of supporting clues like accommodation, motion, luminance dynamic range, binocular rivalry, field of view and so on, I came to a realization.  I realized that when non-vergence depth clues weren’t complementary that those elements or perceptions in conflict required suppression to continue viewing without some sort of physical effect occurring (typically unpleasant such as headache, nausea, etc.).

My paper is a start to the investigation of the importance of supporting perception cues as it relates to stereovision.

*Vergence is the simultaneous movement of both eyes in opposite directions to obtain fixation and the ability to see depth.

*Accommodation is the automatic adjustment in the focal length of the lens of the eye to permit retinal focus of images of objects at varying distances. It is achieved through the action of the ciliary muscles that change the shape of the lens of the eye.

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Filed under 3D, 3D HDR, 3D Health Issues, 3D Motion Picture, 3D Photography, autostereoscopic, binocular disparity, binocular rivalry, HDR, High Dynamic Range, Perception Conflicts, S3D, stereopsis, stereovision

Human Perception Conflicts ARE Natural – How About Facts Over Drama?

Every day there seems to be a new article in a magazine or newspaper forecasting health problems and looming dangers with regards to all things 3D.  Most cite the example of focus decoupled from convergence. They say things like “this 3D stuff is unnatural” and do their best to sensationalize and dramatize for the purpose of selling more magazines.  They do it because that strategy works. You can’t blame them for wanting to sell more magazines. But when trade magazines like Broadcast Engineering jump on the bandwagon this “National Enquirer” style journalism becomes troubling. See their article:

This article was brought to my attention by a fellow member of a professional group that authors Blu-ray and DVD content.  Much of the basis for articles like the above stem from the premise that perception conflicts that occur with 3D illusions are unnatural and therefore are harmful with potential health hazards looming large. Then they point to anecdotal evidence that people experience headaches and nausea and one article exclaimed that someone died as a direct result of watching Avatar.

I’d like to bring some common sense observations into this dialog. First, human perception conflicts happen all of the time in nature. There is nothing unnatural about it. Perception conflicts also happen in outer space and inner space (ocean). If the brain wasn’t able to suppress perception conflicts we would not be able to travel on a boat or airplane or submarine. We certainly would not be able to travel into space where the number of perception conflicts go off the scale. Think about it, even with rigorous training and preparation, many astronauts experience nausea and headaches when they go into space. It is a natural human response to conflicting perceptions as processed in the brain. Some people have more difficulty with conflict suppression and therefore present more significant side effects. While some might argue that Buzz Aldrin must have experienced permanent brain damage as evidenced by his willingness to participate in the Dancing With The Stars TV program, the evidence is that after a time back on earth astronauts reintegrate perceptions that no longer conflict.  (Buzz perhaps requires additional study ;^)

In a previous blog post I talked about decoupling focus from convergence. That is one of the leading issues that people use to justify an opinion that 3D is inherently unnatural and dangerous. They ignore that those who produced the movie Avatar took great pains to mitigate that disparity by using toe-in cameras and keystone correction. Indeed, many found Avatar one of the most pleasing and easiest to view 3D movies they had ever seen. But Avatar did have elements of focus/convergence conflict as well as camera shake (I wasn’t shaking in my seat but the visual was shaking) and super fast scene jump cutting (last I checked there weren’t instant Star Trek like transporters that could beam me around in real life) and many other “unnatural” perception conflicts.

My thought is that it is common sense for filmmakers to spend time understanding the ramifications of perception conflicts and to perhaps reduce or minimize them especially in the beginning parts of the movie. This should provide a greater comfort level for the audience and especially for those with lower tolerance to perception disparities. Just as there are some people who simply can’t see 3D for various reasons, there are people with greater sensitivity to perception conflicts. This should be studied in a scientific way and proper consideration given to educate everyone involved in a factual and scientific manner.  3D filmmaking is both art and science and it certainly can improve dramatically from where the bar currently sits.

Finally, those who have problems watching 3D movies should be encouraged to seek more information about their condition. There are many ways that their experience can be improved, whether through vision therapy or other measures. The notion that 3D tech is somehow bad is very misguided. We should open our minds to the possibilities, not close our minds with unjustified prejudice and misinformation. If we weren’t willing to work through the ability to suppress perception conflicts we never would have got on a boat and humans might very well have become extinct due to their inability or unwillingness to adapt to a dynamic environment.

I hope that common sense will prevail and that all of us will seek to expand our horizons and enjoy all that viewing with stereopsis can provide in both our real world experience and within the realm of entertainment and presentation.

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Filed under 3D Health Issues, 3D Motion Picture, Perception Conflicts, vision therapy

3D – Present A Different Image To Each Eye – Simple, Right? Wrong!

Those of us with “normal” vision see the world with our two eyes in 3D all of the time. We see the space between things and perceive distance, size, texture, etc.

It’s different when you go to a 3D movie or look at one of my autostereoscopic photographs because you are looking at a flat surface and perceive 3D by way of an optical illusion. There are many subtle differences (and many not so subtle) between normal “seeing” and watching a 3D movie that are important to understand and consider. The biggest difference is that for normal viewing the 3D is “real”. You see an object in front of another object and you perceive the distance. When you reach out to touch the object, that perception is verified. A 3D movie on the other hand is created with an optical illusion. It is made possible because our eyes/brain has an amazing capability to decouple focus from convergence and see and perceive the illusion as if it were real.

Some of you are asking, “What does decouple focus from convergence mean?“.

For normal viewing our eyes focus and converge on the same point in space (the thing we are looking at). Just like separate camera lenses, each eye focuses on an object independently. Then our brain processes those two retinal images into a single image with depth. Because the focusing and merging is done separately, we can perform a trick whereby we fool the brain into processing retinal images that converge at a different point from focus. The only thing the brain cares about is the alignment, size and similarity of the images on each retina. It doesn’t matter what the focusing distance is. Our brain just totally disregards this disparity… or does it? Since most people seem to be able to perceive 3D looking at 3D movies, we just make that assumption. My guess is that our brain does enable our perception of focus distance but that we suppress the conflict that happens with a 3D movie in the same way we suppress other perception conflicts (think flying in an airplane for example where our inner ear conflicts with what we see). Perhaps some of us aren’t able to suppress this conflict as easily and manifest some sort of discomfort with the experience; like getting a headache or feeling nausea.

However, it is generally thought of as a “given” that this isn’t a big deal and that perception conflicts occur in nature and the brain just “handles it”. I think that is probably true – but I’m not a scientist or doctor and it would be nice to read that my opinion has some basis in true science.  Perhaps it does and someone will comment?

You still might be wondering how a 3D movie decouples focus from convergence. The fact is that it has to do that. The motion picture screen has to be the point of focus at all times. That is the source of the reflected light and the focus point of the projector in the back of the theater. The left eye and right eye images will be offset from each other based upon whether the objects depicted are in front of the screen or going into the screen. The eyes converge or diverge to align the objects on screen but the point of focus is always the screen surface. At this point, I just have to jump up and down and say THAT IS PRETTY AMAZING!!!  Our brain is really incredible and adaptable in a way that we don’t even have to think about.

Stay tuned for more… coming soon ;^)


Filed under 3D, 3D Motion Picture, S3D, stereovision