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Advice needed! Huge BMCC RAW DNG issue :/

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Chaz Wren
Advice needed! Huge BMCC RAW DNG issue :/
on Aug 12, 2013 at 5:47:13 pm

Hi all,
We've got a big issue following a recent green screen shoot on a 2.5k BlackMagic Cinema Camera. We've never shot with this cam before, and foolishly assumed it'd be similar to something like the F55, in terms of RAW DNG results.

I've uploaded a couple of DNGs from the shoot to illustrate the problem:

All the data seems to reside in the highlights when we look at the scopes, leaving us with little control over the shadows.

We expected a super flat image, we've shot RAW on an F55 before and it graded beautifully. But this BMCC footage is causing us a huge headache :/ We've tried pulling the RAW DNGs into Nuke to key, but we're getting nowhere fast. I'm sure its something we're doing wrong, as we're new to the BMCC workflow, we're just hoping that we didn't actually manage to overexpose it on shoot. The waves looked fine on our monitor on shoot, and we were told by many to push the exposure much higher than we'd normally do, so we did...
We were advised by a rep at BlackMagic to output a ProRes mov (weird, compressed choice?) from Resolve and use that to key with in Nuke. We tried this with a ProRes 4444 file, and unsurprisingly it introduced a whole load of noise to our footage, which made keying even harder.

I can honestly say that, as it stands, this footage is proving harder to key than our stock AF101 ProRes 422 plates. Which seems more than a little odd.

We were also advised by the BlackMagic rep to change our colorscience in Resolve to ACES, which we did. We've tried leaving the clips with no colorspace, we've tried changing the colorspace to BMD Film, we've tried exporting as ProRes movs, DPXs and EXRs. EXRs gave us the best results, but still the footage looks terrible. Much worse than any BMCC examples we've seen online.
Whatever we do, we seem to have a bunch of plates that simply won't key cleanly.

Can anyone help? We're really stuck on this one, and the deadline's only getting closer :/

A huge thanks in advance for light that anybody can shed on this situation.

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