More Proof 3D Sucks

It has been a while since we had a proper rant, James Cameron must have been keeping his head down, but the old 3D debate rages on and we have a new big hitter on our side. Walter Murch, film editor and sound designer extraordinaire, has written a letter to Roger Ebert, film critic… extraordinaire, to explain why 3D just doesn’t work.

It has a lot to do with the way our eyes focus and how a 3D film is all the same distance from our face, making our eyes focus at a different distance to which they converge… I’ll let Murch explain:

“Hello Roger,

I read your review of “Green Hornet” and though I haven’t seen the film, I agree with your comments about 3D.

The 3D image is dark, as you mentioned (about a camera stop darker) and small. Somehow the glasses “gather in” the image — even on a huge Imax screen — and make it seem half the scope of the same image when looked at without the glasses.

I edited one 3D film back in the 1980’s — “Captain Eo” — and also noticed that horizontal movement will strobe much sooner in 3D than it does in 2D. This was true then, and it is still true now. It has something to do with the amount of brain power dedicated to studying the edges of things. The more conscious we are of edges, the earlier strobing kicks in.

The biggest problem with 3D, though, is the “convergence/focus” issue. A couple of the other issues — darkness and “smallness” — are at least theoretically solvable. But the deeper problem is that the audience must focus their eyes at the plane of the screen — say it is 80 feet away. This is constant no matter what.

But their eyes must converge at perhaps 10 feet away, then 60 feet, then 120 feet, and so on, depending on what the illusion is. So 3D films require us to focus at one distance and converge at another. And 600 million years of evolution has never presented this problem before. All living things with eyes have always focussed and converged at the same point.

If we look at the salt shaker on the table, close to us, we focus at six feet and our eyeballs converge (tilt in) at six feet. Imagine the base of a triangle between your eyes and the apex of the triangle resting on the thing you are looking at. But then look out the window and you focus at sixty feet and converge also at sixty feet. That imaginary triangle has now “opened up” so that your lines of sight are almost — almost — parallel to each other.

We can do this. 3D films would not work if we couldn’t. But it is like tapping your head and rubbing your stomach at the same time, difficult. So the “CPU” of our perceptual brain has to work extra hard, which is why after 20 minutes or so many people get headaches. They are doing something that 600 million years of evolution never prepared them for. This is a deep problem, which no amount of technical tweaking can fix. Nothing will fix it short of producing true “holographic” images.

Consequently, the editing of 3D films cannot be as rapid as for 2D films, because of this shifting of convergence: it takes a number of milliseconds for the brain/eye to “get” what the space of each shot is and adjust.

And lastly, the question of immersion. 3D films remind the audience that they are in a certain “perspective” relationship to the image. It is almost a Brechtian trick. Whereas if the film story has really gripped an audience they are “in” the picture in a kind of dreamlike “spaceless” space. So a good story will give you more dimensionality than you can ever cope with.

So: dark, small, stroby, headache inducing, alienating. And expensive. The question is: how long will it take people to realize and get fed up?

All best wishes,

Walter Murch”

Why 3D Can Be a Headache

With 3D releases becoming more and more common those suffering from nausea or headaches will be looking for an answer to the problems which take all the fun out of the 3D experience. Luckily there may be solutions.

The nausea felt by some can simply be explained as motion sickness. The immersive images tell your body it is moving while your body actually remains still; this makes the brain all confused, and when the brain gets confused we get nausea. This can be cured the same way as any other motion sickness; wrist bands, pills, or whatever works for you.

Headaches are all to do with the eyes. The first problem which cannot be helped by the viewer and is related to the fact that whatever you are looking at, no matter how “close” is it to you in the 3D film, all objects are the same distance away from you on the screen. When an object flies from far away to right in front of your face your eyes expect to have to adjust to keep it in focus, with 3D they don’t have to. Your eyes are not having to work to keep an object in focus but are constantly expecting to have to, this conflict can lead to a headache, and there’s not much you can do about it.

A second cause comes from the fact that not everything is in focus. Any shot in a film is composed of various objects and planes, some in focus and some not, and in a 3D environment the brain expects to be able to focus on anything it wants; in a 3D film these two facts come into conflict. If your eye wanders from the particular part of the frame in focus and attempts to fix on something out of focus it will have real trouble. Headaches can arise from the eye trying to focus on the unfocusable, as not everything is constantly in focus a wandering eye will run into difficulties. The simple solution here is to only look at what you’re supposed to look at, easier said than done if the frame is filled with stunning, out of focus images.

So if you do suffer with 3D movies take whatever precautions you’d take on a long car journey and only look at the part of the screen that is in focus. If you still get headaches then perhaps 3D isn’t for you just yet, and if you can watch 3D without any problems then… good!

The problems of headaches are discussed at Rabbit+Crow and shadowlocked.