Problems on Depth of field in HD comps.
by Ricardo Vilarouca
on
Mar 20, 2008 at 5:04:41 am
Hi guys,
We're having some strange problems for some animations made at 2084 x 1230 pixels (it's the output render size asked by the pos-production house for a movie we made some animations).
The main problem - till now the unsolved one - it's some problems we had detected in animations that used 3D cameras an Depth of field in higher resolutions.
It's important to say that all animations were done in 1920 x 1080 so the re-scaling to this output a little bit larger it's probably not the problem. The images are in good size too, everything cleaned and "photoshoped" OK too. :D
We have 2 distinct problems:
1) An animation with 3d cameras and hard-worked depth of field creates some kind of hard edges from focused area to the unfocused ones. It's like some kind of "noised line" in the boderline between the focused areas and the beginning of "blur" of the unfocused areas. To describe the situation: It's a 3d camera passing by a 3d layer of a geographic map. The depth of field creates a kind "strip" of focus in the middle of screen that "blurres" to top (far from POV) and down (near from POV) of the screen. So we have 2 "noised lines" more or less in the middle of screen, top and down of the focused area. Is that clear? It's really hard to explain that. :D
We tryed to change the project to 16bit, tryed to change the shadow map to higher values. Nothing worked till this moment. We are considering to abandon the After native DOF and emulate that by some "lens blur" alternative. Our conclusion is that the After 3d cam fails in emulate DOF in very high resolutions, since we never had this problems in lower resolutions (we are in some kind os "transition age" in resolution "standards", I think.).
2) Second problem is simpler, but a little bit weird. In a 3d comp with only six 3d layers, the cam starts in close and starts going far and far, so it stops and you can see the "big picture". During this "going far and far" some areas of some layers (it happens with 4 of 6 layers. And in different moments) flick during a single frame. But its a very singular "flick". When you compare 2 or 3 frames with the flicker one, in photoshop, you see that the wrong frame looks brighter (most of them in only some areas of the frame).
We still think that is something in DOF of After cam in high resolutions:
First: cause if you turn the DOF off the problem dispears (it happens in all cases related here).
Second: When we all did this kind of use on cameras in lower resolutions (we did a lot) it never happened.
Anyone has any suggestion? Maybe some relationship between camera parameters and DOF. Well any sugestion will be welcome.
Thanks all for any contribution, and everyone for just read this poor english explanation :D
Re: Problems on Depth of field in HD comps. by david bogie on Mar 20, 2008 at 3:10:57 pm
And, yes, there are some problems with AE's depth of field functions. They don't get talked about very often because the problems are directly proportional to the complexity of the scene.
I know of no cures or solutions except to lower your expectations.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: Problems on Depth of field in HD comps. by Ricardo Vilarouca on Mar 20, 2008 at 5:28:05 pm
In fact we're trying to lower the director's expectations :D
I don't really believe we have noticeable problems here (well, the "flickering problem" it's visible, yes.). But director and editors see this thing all the time, frame by frame, and this situation makes any detail (or error) VERY noticeable.
We didn't know nothing about limitations in depth of field function (ok, we can wonder that, the world it's not perfect we know...). At least till this moment.
What could be the solution? Lower the expectations is not an alternative. Could the expectations get lower when the resolution's getting higher? (ops! well..."raising" it's better).
The DOF of 3dsMax has severe limitations, more than afterFX even (in my rumble opinion). Combustion has severe limitations in other options (like parenting for example) that makes me passing far from it (I don't know if DOF limitations is another problem, but if 3dsmax has, combustion may have too).
I don't know if another software solution could be a solution (well, not for THIS job. The budget is already over :D). I accept any sugestions.
I got myself wondering if some kind of expression linking lens blur (or another lens blur plugin) and camera parameters could be a paliative solution (till adobe and the others softwarehouses discover that this kind of things have to work in complex scenes. Everything is getting more and more complex always :D). But I can't program anything, and it's only a sugestion. But if anyone does I'll be the first to clap my hands.
[This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."]
Hey!!! I've read the manual!!! Lots of times!!! :D
