Art that shows visual effects of looking from close distances?

November 29, 2010 8:35 PM

If you lay your forehead on the palm of your hand and look down at your forearm, you get a distorted view of the connection between wrist and forearm, as well as a sort of "ghost" forearm silhouette at the margins. What's this called, why does it happen, and are there any paintings or other art that captures these effects?
posted by shivohum to science & nature (13 answers total)

Oh, the joy of binocular vision. I suggest reading up on parallax.

Or maybe skip that and go straight to binocular disparity.
posted by cardioid at 8:51 PM on November 29, 2010

As for the "ghost" forearm silhouette, are you just seeing the different images from each eye? If you close one eye, then the other, and watch carefully what you see, does this observation explain the "ghost" forearm silhouette?

(I just ask, because having a lazy left eye that doesn't see too well as a kid, I momentarily wondered how it was that I could see "through" my own nose -- turned out I was seeing out my left eye.
posted by smcameron at 8:52 PM on November 29, 2010

I, er, get that parallax effect even just looking at my hand a few inches away. (Should I be concerned?)

Also, in the movie Hausu, a girl opens and closes her eyes, alternating each eye, to get the Camera 1, Camera 2 effect.
posted by Sticherbeast at 8:58 PM on November 29, 2010

Also, in the movie Hausu, a girl opens and closes her eyes, alternating each eye, to get the Camera 1, Camera 2 effect.

The real question is, could you present a frame from camera 1 then a frame from camera 2 both to the same eye and get the binocular effect.
posted by jamjam at 10:27 PM on November 29, 2010

The real question is, could you present a frame from camera 1 then a frame from camera 2 both to the same eye and get the binocular effect.

No- otherwise you wouldn't need 3D glasses, and 3D TVs could just flicker between the two views and you'd have 3D.
posted by BungaDunga at 12:16 AM on November 30, 2010

BungaDunga is correct; your eyes have to see different things in order to perceive three dimensions. That's why people with one eye can't truly see in 3d. That doesn't mean they have absolutely none of what most folks consider depth perception because some of that is actually picked up from other cues, but it does mean they're going to have trouble parallel parking or seeing Avatar at the 3D IMAX.

I don't know about paintings, but there are plenty of images and art that make use of parallax. Google stereogram or... uh... I don't know what you would google for the other kind. "3d image" gives one or two examples, but most are not what I'm talking about.
posted by Justinian at 2:13 AM on November 30, 2010

The "Frankfurter illusion" takes advantage of a similar phenomenon.
posted by NoraReed at 2:46 AM on November 30, 2010

Stereoscopy.
posted by Ahab at 2:48 AM on November 30, 2010

About the only thing I can think of in art is the work of Patrick Hughes. They really need to be seen in real life, and walked around for full effect. The video on his site gives an approximation.
posted by fire&wings at 4:33 AM on November 30, 2010

To further convince you that Justinian is correct, I'll share that I don't have binocular vision at all and when I put my hand on my forehead and look at my arm, I don't see anything special.
posted by easy, lucky, free at 7:30 AM on November 30, 2010

I didn't say it would be easy, though I think pigeons may be doing it (generating one-eyed depth perception by looking at something then quickly shifting to another head position and comparing the images).
posted by jamjam at 10:01 AM on November 30, 2010

The real question is, could you present a frame from camera 1 then a frame from camera 2 both to the same eye and get the binocular effect.

I've taken some photos with a similar-ish effect, but it's still overwhelmingly true that true 3D comes from binocular vision. Follow the instructions below the photos to see the gifs in their "wiggle 3D" mode.
posted by Sticherbeast at 10:53 AM on November 30, 2010

That's part of what Picasso and Braque were after with Cubism:

In cubist artworks, objects are broken up, analyzed, and re-assembled in an abstracted form—instead of depicting objects from one viewpoint, the artist depicts the subject from a multitude of viewpoints to represent the subject in a greater context

posted by AsYouKnow Bob at 7:07 PM on November 30, 2010