Now that the novelty has worn thin and we can consider the issue with a clear head, it appears clear that 3D movies are a nuisance for the audience, add no real value to films and impose a number of cumbersome limitations on filmmakers. There is also a fundamental biological conflict that imposes a hard limit on the human tolerance of this technology.
The biological conflict
As explained in the article on how 3D movies work, 3D vision is the result of the slightly different perspective observed by each eye. In nature, our eyes focus and converge at the same distance, regardless of whether you are looking at a distant mountain or an article a few inches away from your face.
The conflict arises when we watch a 3D film, because the movie screen is at a fixed distance but the 3D images, aided by the 3D glasses, trick our eyes into converging at a different distance while maintaining focus on the screen. Hence if an object is made to appear to be three feet away in a 3D film, your eyes converge in a manner consistent with that distance — they converege as if they were really looking at an object three feet away — but they still need to focus on the screen, which is at a much greater distance. This discrepancy between the focus distance and ocular convergence distance induces strain, which is why some people cannot tolerate 3D movies and get headaches. This is probably an intractable problem, which means there is no realistic prospect of an economically viable solution being developed.
3D imposes technical limits on filmmakers
As a result of the focus-convergence discrepancy outlined above, the brain needs extra time to process the conflicting data it receives from our eyes. One consequence of this additional processing time is that the film edits cannot be too fast, because each cut entails a change in focus-convergence discrepancy which the brain must re-process from scratch. For the same reason, panning can’t be too fast either, or the image will exhibit a strobe effect. As a filmmaker, I am not willing to make compromises on my technique to accomodate a technology that stresses the audience in return for no upside whatsoever.
3D adds no value to films
All of the above is a rather hefty price to pay for a technology that adds no value to a film. Indeed, with the strain induced by the focus-convergence discrepancy and the nuisance of those wretched 3D glasses, a strong case can be made that 3D is a burden that detracts from the story.
This is one point on which I disagree with James Cameron, who claims that 3D draws the audience in and makes them more “present,” making the experience (and recollection thereof) more vivid. Neither I nor anyone with whom I have discussed this issue has observed this effect. The films that most touched our hearts were made in gorgeous 2D and we had no difficulty immersing ourselves in the narrative. The compelling story, convincing characters, gorgeous cinematography and judicious editing enchanted us far more than an overwrought 3D illusion ever could.
As a case in point, I have no warm feelings for Avatar, which was shot on 3D at considerable cost, but I never tire of watching The Abyss, a vastly superior movie shot in 2D a full 20 years before Avatar (both directed by Cameron).
I have also noticed that 3D glasses make the movie screen look smaller than it really is — a disconcerting feeling that doesn’t help in the least.
In short, the argument that 3D engenders superior audience egagement is fanciful in principle and unproven in practice.
The 3D pretext
It is self-evident that if Hollywood invested the considerable funds it took to develop 3D film technology, a persuasuive business case was identified, and 3D did indeed account for an initial surge in ticket sales. However, now that the novelty factor has dissipated, the popularity of 3D with film audiences has predictably declined. It is not unreasonable to suspect that 3D was developed as a pretext to charge inflated ticket prices and revive an industry that was desperately short of ideas. Fair enough, but the sooner this dynamic exhausts itself, the better.
The film industry should focus on real production value
Now that we appear to be at the tail end of the 3D experiment, the film industry will have to give careful consideration to how it will generate real value for film audiences. The fundamentals haven’t changed: high-value films that can be enjoyably watched repeatedly — thereby generating long-lasting revenues — require the careful assembly of top-notch scripts and correspondingly talented cast and crew. There is no durable way around this requirement, and the sooner the film industry embraces this reality, the sooner they can get back on track.