THE BIG PICTURE

I just saw Shrek 4D The Final Chapter Forever After...whatever in Imax 3D. (I really wish DreamWorks had settled on one name for its marketing campaign!) I went because I want to see as much 3D as possible, but after reading several lukewarm reviews, I was prepared to be unimpressed, at least with the story.

I was pleasantly surprised. Yes, it's basically a retelling of It's a Wonderful Life, but a very clever one with lots of laughs. Unlike some reviewers, I enjoyed all the pop-culture references and music, especially the Pied Piper with his rockin' dial-o-matic flute.

As for the 3D, it worked pretty well—with the usual caveats. Fast motion, particularly way out in front of the screen plane, lost lots of detail in a smeared, stuttering mess, and the filmmakers included plenty of gimmicky shots that shove stuff in your face, which is more annoying than impressive.

On the plus side, I noticed that the depth of field was fairly narrow in many scenes, putting the background out of focus. One of Roger Ebert's complaints about 3D is its supposedly infinite depth of field, but here's a counter example that proves it doesn't have to be that way.

I found myself musing about the importance of a really big screen to the 3D experience. Of course, an Imax screen is among the largest available for moviegoers, and it completely filled my field of view. Also, the glasses are larger than those you get for non-Imax 3D movies, which also helps improve the immersion factor. If commercial theaters need to offer something consumers can't get at home, a huge image fills the bill nicely.

Interestingly, I discovered that the dual-projector Imax system used linear polarization—tilting my head, I could see the left and right images in both eyes. Of course, two projectors can throw a lot more light, which is critical for 3D on such a large screen. But why use linear instead of circular polarization, which exhibits no crosstalk when you tilt your head?

After the show, I asked the theater manager about the silver polarization-preserving screen. Do they replace it with a white screen for 2D presentations? No. Okay, so I won't be seeing any 2D Imax movies in that theater. I also asked how much the Imax and smaller RealD (circular-polarized) glasses cost the theater. Each pair of RealD glasses costs about $8, while the Imax glasses are $12. I expected the Imax glasses to be more expensive because they're larger, but I didn't think either would be as much as I was told.

I'm happy to report that I felt no ill effects after watching the entire movie, and as I said at the top, I thoroughly enjoyed the story and most of the 3D. Will it be as impressive on a plasma or LCD? Of course not. Will that derail the adoption of 3D at home? I suspect the commercial-theater owners hope so.