I'm not about to pretend to be a big expert on the art/technology of 3-D movies, but I do know a few things: 1. I once spent an afternoon on the set of the My Bloody Valentine remake, and (say what you like about the movie) those guys spent a lot of time working on a massive camera / monitor hook-up that looked like a cat-scan machine combined with a airplane cockpit. 2. As a child of the '80s, I grew up suffering through several horrid 3-D movies (research the year 1983, movie freaks), but even the worst of those flicks were created with the intent of being shown in 3-D. For all its lameness, even something like Amityville 3-D was composed, framed, and photographed with the three-dimensional exhibition process in mind.
But guess what, moviegoers? Someone out in Hollywood figured out a way to "3-D-ize" an already finished film. Yes, a film that was (again) composed, framed, and photographed with a flat surface in mind is now being retrofitted with a gauzy, tacky 3-D "conversion" process that may look great on the marketing materials ... but really suck eggs when it comes to entertaining an audience. Oh, and it's more expensive, too. Suckers.
The nicest thing I've heard about the 3-D version of Tim Burton's Alice in Wonderland experiment is this: "I'm not really sure why it was in 3-D." (I've heard much nastier things about the movie itself.) 3-D films -- be they actual 3-D productions or after-the-fact "conversion" jobs -- demand higher ticket prices, you see, which is why a perfectly and happily mindless piece of popcorn entertainment like Clash of the Titans will be arriving this weekend in both the wow-fancy 3-D and the "lame old" 2-D varieties. The studio makes a few more bucks from the families who wander into the 3-D presentation, but here's the problem: those ticket-buyers are wasting their money.