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Re: Curves and Bit Depth - was Sigma fp

Re: Curves and Bit Depth - was Sigma fp


John Brawley
 


On Dec 27, 2020, at 2:59 PM, Pawel Achtel ACS <pawel.achtel@...> wrote:

Ø  [Mitch Gross] Uncompressed RAW is the best quality — so what? It is a more burdensome workflow because it does not deliver an immediate result in the form most clients want and it requires more memory which means more time in transfers.

You are confusing two things: Log curve (which saves very little space) and compression (which requires additional compression in camera and decompression in post).

In my many years of experience with DNG as a DP, simply because it is such an open format, it’s also the most likely to get screwed up and mangled in the post pipeline.  Every system opens it a different way despite the metadata and loaded tables.  PS, Google, apple finder, chrome, Resolve.  You open a single frame in any of those platforms and they all look totally different.  No one can work that way for a "lay” hand off.  It requires more oversight from the DP, which these days is typically less possible.

With increasing camera resolution the DNG file sizes also shoot up commensurately.  Even though hard drive space costs are lowering, the rate of file size increase with 4K+ files in DNG negates those cost savings in my view.   

Tell me the data rate for an 8K uncompressed DNG recording in-camera and then let’s run the numbers on what that is like for post compared to REDCODE @ 8K.  What kind of media can even do 8K uncompressed DNG ?  

Uncompressed is just as unwieldily for even competent post facilities.   My last two shows are very large budget for TV (10 million + per ep).  

On one everyone LOVED the Alexa 65 (which only shoots Arri RAW) in my testing, in combination with DNA primes.  It was the chosen camera package until post found out about it.

The Arri RAW data offload went from a single person on a 12 hour shift to three people across 17 hours to get it turned around each day even with HDE. Not only that, the delay for any VFX pulls went up astronomically. They also hit us for a lot of extra hard drive space charge.  

The main reason we didn’t go Alexa 65 was because POST said they couldn’t offload, process and turn those size Arri RAW files around fast enough.  And that meant it ALSO cost more.   Remembering that many shows do post in another country and “the internet” is how files are moved around, you are truly DREAMING if you think DNG is genuinely just as manageable as compressed RAW formats.  Sure at a local hardware level maybe, but not once you have multiple instances and you need to move those files around...

While the computational power to process a DNG is less, the bandwidth required is a heck of a lot more onerous on balance.  No not for an individual system, but when you have to move all these files around to multiple places, bandwidth is a problem.  Computing horse power isn’t so much of a problem to overcome.  No one wants to wait for DNG’s to be moved over the internet.  And that’s how post is done.

So instead we went to Arriraw from a regular SXT, (GASP less than 4K for a major streamer) because the streamer AND post didn’t want the “overhead" of 4K+ uncompressed.  And this was a 10 million per ep show.

Save for a giant budget film maybe, or special application where less compression actually makes a difference, no one is going to willingly pay for uncompressed DNG.  That’s my actual real world experience in the last two years of bigger budget TV,



BRAW is not widely supported on anything but Resolve and even Resolve requires expensive GPU. RED RAW requires decent GPU too. 


Pretty sure you’re quite wrong here. BRAW is actually widely supported.

Resolve obviously, but also

Adobe Premiere
Avid Media Composer
Silverstack (Used by many for dailies ingest / transcode)
On-Set Dailies (Also used for dailies processing / transcode)
Shot Put Pro (used for ingest)
Scratch
Baselight
Lightworks
Edius
PrimeTranscoder
Kyno
Syntheyes (match moving post software)

Basically the only thing BRAW isn't currently supported in is FCP. 


Ø  [Geoff Boyle] Of course we need objective measurements but ultimately we work in a world where taste is more important than fact.

Yes, but if we don’t change it no one else will. It amazes me how many DOPs do not know how to produce or read MTF graph or measure dynamic range or measure colour accuracy or gamut of a camera. As part of the industry we need to stick to the fact and objectivity. It is important. 
 

Pawel, I think you’re projecting (and judging) what “creative” people want.  How would you know ?  I personally don’t think MTF’s matter much when everyone is detuning lenses these days.  Resolution isn’t the only property of a lens and in my view, for most cinematographers and creative users of lenses, it’s way down the list of qualities that are desired.

Just like the argument about “accurate” colour and “nice” colour.  

While MTFs are useful to some, they are totally irrelevant to others.  A metric that’s important in the work that you do, isn’t always what’s important to another image maker and frankly I think that’s why most don’t care much for MTFs.  What does it “tell” you how it looks on a human face or how the lens performs with lots of backlight.  

Isn’t the MTF just one of many things that “could” matter to the individual creative choice of an image maker ?


John Brawley ACS
Cinematographer
Los Angeles

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