-
Tracking Slow-Motion Object Falling Out Of Focus
I’m VFX supervisor on a pilot next week. The director wants the actor to drop a metal sphere about three feet in slow motion at 96fps. He plans to, “make it almost appear to stand still”. The sphere has cut outs and I plan to fill the area behind the cut outs with green paper, stick a couple tracking markers in there, and composite some cogs and gears inside.
But if the sphere is falling out of focus, all my green (and markers) are going to blur out of focus as it falls. The DP tells me it’s pretty much impossible to maintain depth of field on the sphere unless he racks focus – which isn’t what we want. Does anyone have any suggestions?
-
7 Replies
-
I talked to him and they already upped the frame rate. Apparently I missed that while multitasking during yesterday’s meeting. I also have the ball and have run what tests I can, but my conclusion was basically that the focus is an issue. My best idea so far is to get a still of the ball when it’s in focus and animate that to scale with the real ball, compositing the interior elements first, then de-focusing it out to match the blur of the real ball as it drops.
-
Why not just create the sphere element entirely out of CGI? You’ll have reference shots from on-set; get them to shoot a pass without the ball present, and see if it turns out better to just re-create it.
The other alternative is to make sure that the shot is framed such that the ball falls even with the focal plane, so that focus is NOT an issue.
Is there a storyboard available so that you know what angles they intend to get? That might help you to advise them. Realistically, as a VFX supervisor you (or a trusted member of your team) should be present on-set, so that you can have input to help make the shot look as good as possible.
-
My Maya skills are weak. I’m mostly a compositing artist. But I appreciate the suggestion.
I do have boards. The shot is a POV and the director wants focus to stay on the actor’s hands as he drops the ball. I think overlaying the falling ball with an in-focus still (as postulated above) will work though. I don’t want it to rotate anyway… If I have time, I’ll run another test though.
-
You might be able to do it in AE with the CC Sphere as the basis. Tough to say without seeing what it looks like (metallic? matte?).
-
It’s rusted metal. I think we’ll get better texture results out of the real sphere, but I plan to use CC Sphere on the interior workings.
-
Probably a bit late for your purposes, but I would suggest that the actor drops a placeholder object that can be tracked easier (such as a tennis ball) instead of the real object and you compose the “dropped object” in post altogether, adding motion blur and depth of field in AE.
-
That’s a good idea. We have shot, but there’s some talk of pick-ups and I’ll keep it in mind if that becomes an option. Thanks!
Reply to this Discussion! Login or Sign Up