Debayer importance for Dailies and QC.

[Frank Cueto]

After reading several threads about dailies and debayering I decided to share some thoughts & observations and maybe learn something in the process.
At times digital cameras (looking at you RED, but not exclusively) will drop a line of pixels vertically (never seen this horizontally though), have a dead/stuck pixel or display fixed pattern noise.
Sometimes this is caught during the dailies process and sometimes its only noticed once we get to DI.
Another interesting thing is that some of these artifacts only make themselves present under a full debayer but NOT under a half or lesser debayer.


Herein lies the fulcrum of this argument.


When we do half-debayers and other compromises, are we putting ourselves at risk of not having enough fidelity in our intermediate footage as to miss these things? I know it has happened to me in the past
but I had never had an urgent need to delve into this subject since we do our .r3d processing in a dual rocket setup. Now with dragon, RR-X and GPU debayering its starting to become something that I *think* might need a bit more attention from our end
to make sure all is swell.

Some people have suggested adding a QC portion to the process before we start cranking. Although logical and probably well-looked upon by the DoP, I don't know what inefficiencies this might bring to the overall project and if they are a worthy trade off.

any insights out there?

 

[Frank Cueto]

NO takers?

 

[Mark L. Pederson]

When we do half-debayers and other compromises, are we putting ourselves at risk of not having enough fidelity in our intermediate footage as to miss these things?
any insights out there?

Depends on the content and depends on how critical your "intermediate stage" is.

A LONG time ago .... we edited on 35mm film. And you ALWAYS knew when the focus on the eyes was a little soft, etc.

Then we edited in SD from 35mm film !!! Then we edited in HD from 35mm film. So .... same "risks" we have had for years.

The BEST thing - and what IMO is the FUTURE (and for some it's already the NOW) - is no intermediate file. Edit from your negative. Look at the negative 1/2, full, whatever.

 

[Marc Wielage]

I can answer Frank's question this way: many times, in the late 1990s and throughout the 2000s, I encountered situations where we were doing the D.I. on a large screen and the editor would shake his head and say, "jesus! I never saw that before." The problem was that he or she had been editing on (at best) a 24" monitor for months and months on end, and it's a whole different experience when you see it on a 20' screen. Suddenly, you see tiny details magnified that you would never otherwise see.

There are more and more editors that have embraced Ben Burtt's approach, which is to use a 40" or 50" HD monitor and edit standing only about three or four feet away. That way, you will see 90% of any real problems in the image, assuming you're at a reasonably high codec like ProRes 422 or DNxHD 160.

I don't think you suddenly open yourself up to seeing lots of problems in 4K that were obscured in 2K. Generally, the issues I see -- noise patterns, lens dirt, cables on the floor, shooting off the set, digital glitches -- are just as visible as a little QuickTime file on an iPad. At least now, we have the technology to easily make most of these problems go away or at least knock them down by 75%. I have seen dead pixels on rare occasions (with several different cameras), but those were still very visible on a 50" HD monitor.

I typically will see at least five or six bad pixels per day with Alexa footage, but we're talking 1-frame bursts, and it's just 1 pixel. I look on it as the digital equivalent of "negative dirt," nothing that can't be fixed later on at very little cost.

 

[Blair S. Paulsen]

When the hero contracted deliverable from a RED shoot is a 1080 HD master, then the risk of missing something significant enough to be a show-stopper due to the use of proxy media is pretty low. FWIW, I think a lot of folks are pennywise and pound foolish when they put their editors on workstations that cannot offer both decent quality pictures AND snappy response. How much does it cost to deal with the inevitable issues found in grading/finishing?

As more and more contracts start specifying UHD/4K deliverables (even if they are just planning to archive them in the short term), the QC step Frank is seeking becomes more critical. What I've seen, is a great deal more shots where slight focus buzzes really scream out. Many of us in the biz roll our eyes at the number of soft focus shots we see every day even on well budgeted scripted shows, but very few "civilians" even notice. At UHD/4K even the casual viewer, assuming they have good vision and the signal isn't compressed to death, will be much more aware/distracted.

A good focus puller is still the best option as they can subtly adjust the timing of focus shifts to correlate with the pace of the scene, story beats, reveals, etc. Obviously not every shooting situation is going to have a skilled human dedicated to managing only focus. Over the last few years we have seen more and more focusing "aids" appear on cameras with varying degrees of usefulness and accuracy. Hopefully the next iteration of focus assist tools will be even better than what we have now. The Canon 70D's Dual Pixel phase detection tech is promising and there are plenty of folks looking to create better tools. With all the sensor real estate at 6K, DOF is thinner. Based on recent testing, for a lot of DPs, the working ISO of Dragon is around 400, so we may be shooting a lot of scenes below T4 for UHD/4K projects. Any tool that can help increase the ratio of in focus to out of focus takes is going to be VERY popular.

Cheers - #19