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Advice needed! Huge BMCC RAW DNG issue :/
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:
https://www.yousendit.com/download/bWJxT201bWdRR2Y1SE1UQwAll 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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17 Replies
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Chaz, it might be worth jointing the official BMD forum and posting your note there. Lots of people with experience with raw in that forum and also the BMCuser.com forum. Hope that recommendation doesn’t break any Creative Cow rules but this sounds like an emergency. You could peruse both forums for general guidance but posting your specific problem seems better to get you quick results.
Rick Lang
iMac 27” 2.8GHz i7 16GB
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I just pulled one of the DNGs into after effects and using adobe’s raw importer I was able to drop the exposure down and play with highlights and mids to achieve a good result. Only problem I can foresee is that the footage is fast motion – you will have a lot of motion blur around the character which will be v hard to key…
What about adjusting exposure in resolve to get the desired effect and then using the keying tool to output a prores file with a transparent alpha channel?
Do you have the full CS6 or CC suite to be able to have a play?
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Thanks Rick,
I’ll get signed up there. I think we may have found a temporary solution. AE Camera RAW is a fall back…Thanks for your advice,
ChazMore RAM, for the love of god we need more RAM.
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Thanks for the advice Tom,
We do indeed have Adobe CC. We managed to get the DNGs working in Nuke in the end, with a little help from the good people at The Foundry 🙂
Happy days!I’ll be posting a quick guide/tutorial on how we did it, later this week. Hopefully it might save someone else the same headache at some point, at least until The Foundry update Nuke to natively support DNGs.
Thanks for your help. And for the record, the motion blur’s going to be a nightmare! We shot at 24, probably should’ve gone higher :/ Live and learn eh? 😉
More RAM, for the love of god we need more RAM.
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Yeah – we did some simple bits with a footballer doing keepy ups recently and even at 30 it was bad. Next purchase is a RED for doing higher frame rates because it seems as though Blackmagic is ignoring this feature for now.
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As another workflow for Future, I would suggest a quick test with this for the DNG’s.
https://cineform.com/products/gopro-cineform-studio-premium
Convert and see how that works for you. Free trial so got some time to check it out. Also might help to take a look at First Light.
Eric-ADK
Tech Manager -
Tom, I’m sure BMD is not ignoring high frame rates, it’s just not a feature of the current cinema cameras. HFR is one of the most requested features to add to their cameras as they concentrate their efforts on delivering a high quality image in raw, ProRes, and DNxHD solution for an economical price. I would expect higher rates perhaps topping off at 48 fps or hopefully 60 fps in the future but that doesn’t help Chaz today! They probably want to achieve this using the full active sensor area (2432×1366 on the BMCC and 3840×2160 on the BMPC4K) because they want you to have the ability to render or downscale your deliverables from the highest resolution available on a given camera. Contrast this with most digital film camera manufacturers that offer very high frame rates by increasingly cropping the sensor. Their approach just takes some more time and likely requires faster processors and better cooling and of course reliable faster recording media (SSDs). So hope you’ll see there is an upside to their approach and they are listening to requests.
Rick Lang
iMac 27” 2.8GHz i7 16GB
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When I posted yesterday I was on the iPad which doesn’t know how to see a raw CinemaDNG image. When I saw it today, I realized you had a very tough green screen to pull off given the relatively slow speed of the sh
Utter. Did you use a 180 degree shutter on that 24 fps clip? Until BMD supports higher frame rates, might be good to use a 45 degree shutter and see if it plays back well enough for your purposes. If the green screen clips are short and sweet, the faster shutter angle may be acceptable. Good luck.Rick Lang
iMac 27” 2.8GHz i7 16GB
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Hi Rick,
Yeah, the motion blur is nuts! I’m going to start properly working on it next week, just been prepping it this week whilst finishing up current projects. I think we shot it at 180 unfortunately, I’ll check with our DP, but from the amount of motion blur, I’m guessing it must be 180. We did contemplate a faster shutter, but we thought we (specifically ‘I’) would try and deal with the extra motion blur from 180, to ensure we kept the fluidity of the free runner when in full motion. Needless to say I’m already regretting that decision now!!
We’ve never shot anything as fast as a free runner on green screen before, so truth be told, we may have somewhat under estimated the true extent of the motion blur we were buying into!! Still, I’m sure I’ll sort it eventually…well, I’ll HAVE to sort or somehow 😉 *gulp*Thanks again for your advice, I think we’ll be shooting 45-90 next time, unless we have a higher frame rate cam of course 🙂
More RAM, for the love of god we need more RAM.
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