Originally published on Twitter Feb 24 2020
To celebrate today's purchase of Shazam 3D here's a thread about stereoscopic (a.k.a 3D) movies.
I used to think that for 3D conversions they use the 2D footage as one eye and then just create a second eye but they actually create two new eyes. The original footage is sort of a center view.
If you switch from left to center to right in quick succession you might think that you'd get a mini version of The Matrix's bullet time. But no, you often get this weirdness.
Suddenly you see all the warping and trickery used. Things are enlarged to cover up more background rather than re-creating the background, things are erased to solve problems, etc.
Look at these guys raving! unts unts unts
Using the left-center-right works as you'd expect in simpler shots though.
Sometimes you get a background object covered up in one eye but visible in the other eye which gets uncomfortable. That was the case with the fire behind Sivana in this shot, so for 3D that fire was painted out to spare you the headache.
To get depth from things like falling snow it's easier to just paint out the snow and replace with CG snow (or just leave it out). Here's flipping between original 2D and one of the 3D eyes. You can see some of the snow disappearing.
Normally I prefer my 3D to go deep into the screen rather than pop out. But a problem with 3D is "ghosting". When you have a bright object against a dark background, the two angles of the bright object can end up visible in both eyes.
Having a movie set at a Christmas carnival at night will present a lot of ghosting challenges from all the lights. One way to fix this is to make sure that the two images converge where the lights are.
This is what it WOULD look like if the convergence was at the girl in the foreground. In a theater this would look like the screen is a window and everything is behind it.
But because of the bright lights in the BG the convergence had to be set much further back which means that the movie "comes out of" the screen instead.
I used to be a much bigger 3D fan. Loved my ViewMaster as a kid, loved my Nintendo 3DS as well as my old timey 3D viewer bought in an antique store. The concept of 3D is awesome.
For film though I think it's not really worth it unless you not only shoot 3D but also change your whole film language to adapt to 3D and take full advantage. And we really need a way of viewing it without glasses. It's all too much of a hassle currently.
I've seen a ton of movies in 3D but when I think back on them my memories are in 2D. I don't remember the 3D. Maybe that's just me though.
As a director I know it's expected for bigger movies to be in 3D and I don't have a problem with that. There's some really cool 3D stuff in Shazam. The priority for me will always be the 2D version though.
By the way, the people who convert movies really get the short end of the stick. VFX are finished last minute and they can't convert shots until then. They have to do a ton of very difficult work in very little time. Hats off to the 3D conversion folks!