Last week, being the Disney purist that I am, I expressed disappointment that The Lion King was only going to be shown in theatres in 3D.
Watching it on the big screen tonight, I actually didn't really feel the 3D experience and I couldn't figure out why.
So I took off my 3D glasses and put them back on, to see if there was a real difference. Now, 3D images on the screen normally look blurry without the glasses, but I noticed when I took my glasses off that only the background was blurry. The foreground was in 2D and not blurry at all. I put the glasses back on and definitely noticed the contrast: Simba was trapped in another dimension. This makes sense, since The Lion King wasn't created in 3D.
I'm not against the effect of depth on the screen, though. I just prefer it to look realistic. Take the opening scene of Bambi. When I watch that movie, I feel like I can walk into the forest. The film was released in 1942, obviously waaay before computer animation and the effect was achieved by placing different planes above one another on different sheets of glass, moving each plane independently. A camera above all the frames takes a picture each time after they are moved. When the film is played, just like with all cartoons, it creates the illusion of movement -- only with this technique the illusion of depth is achieved also.
See Walt Disney explain how the multiplane camera works with examples of it in Disney shorts and the opening scene of Bambi.
Now, doesn't that look more believable? It's easier on the eyes, too...