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Re: Curves and Bit Depth - was Sigma fp

Re: Curves and Bit Depth - was Sigma fp

Brian Heller

What Mark and Mitch have said :-)

I am totally camera, sensor, Ganma curve, Bit Depth, RAW/compressed, post path agnostic.

As David Watkin said: “If they paid me to, I would shoot with the lens cap on.”

Of course, RAW is theoretically “better”, but so what.  For instance,
 if the optics are not 1st rate, all the data in the world isn’t going to help.

I would love to see any DIT or DP (without foreknowledge of the process) to view a final product and identify the camera or lens or the Codec or the bit depth or the post path taken on a given film.

Brian Heller
IA 600 DP

On Dec 28, 2020, at 2:59 AM, Adrian Jebef via cml.news <adrianjebef=yahoo.com@...> wrote:


I swear these threads always derail into a bunch of old farts yelling at each other to slow down. Like, “Don’t push the Camery past 65 or Momma gonna find out!” It seems y’all know best: let off the gas.

Sorry some of you don’t care. Sorry Sigma released a camera that is too powerful. Sorry Geoff doesn’t have any DIT friends with a new computer. And sorry if I offend some fragile DP ego. Oh well that’s the film biz for ya. Ya can’t have it all. Maybe Sigma will add HD ProRes Log recording in the mark ii.

Adrian Jebef

On Dec 27, 2020, at 10:46 PM, Maxwell Geoffrey <maxwell@...> wrote:


     While do agree with most of what you’re saying from a technical standpoint, I think you’re missing the point that Mitch and Geoff are making.
     Firstly, while uncompressed RAW is certainly a gold standard in terms of getting the absolute highest quality recording from a given camera sensor, the files are bigger and do require more attention to be paid to them in post to ensure that the images shot on set are what actually gets delivered in a final deliverable.  Compressed (non-RAW) recordings will work seamlessly in a REC 709 workflow with almost any NLE and grading application, simply requiring a show LUT or power grade to achieve a finished image.  No attention needs to be paid to ensuring that the proper metadata for ISO, white balance, and gamma curve are being used for each shot, and unlike RAW, the shots don’t require any post production noise reduction.  All of this is completely unfeasible on shoots with faster turnarounds, regardless of budget, but especially on lower budget productions.
     Moreover, the space savings of not shooting RAW, no matter how insignificant they may seem on paper or how cheap storage media becomes, ultimately translate to more shooting time on set, less money spent on drives for backups, or both.  Personally, I’d much rather work with uncompressed RAW that was encoded as 12 bit log, because the 25% smaller files compared to 16 bit linear mean that I get a fourth take on a card if I need it or more later if I don’t, and frankly, I can’t think of a single time when I haven’t been able to roll off the highlights in a grade to my liking because a few extra pixels were encoded at (for example) code value 4071 instead of whatever the 16 bit linear equivalent of 4071.25 may have been.
     In a realistic situation, shooting a short turnaround project on a camera like the C300 Mark III and choosing to shoot 10 bit XF-AVC at 410Mbps over the 12 bit 1Gbps compressed RAW nets me 144% more recording time and a 59% savings in media costs, and if I want higher quality, I can shoot at 810Mbps and still net 12% more recording time and offer a space savings of 19%.  Both of these options save the headache of shooting RAW and then having to oversee the entire post production color management pipeline, which is frankly nonexistent on this kind of project.
     To wrap up on less of a technical context, while I do agree with you that DPs should definitely understand the technicalities of the entire image creation and finishing pipelines, those technicalities often don’t matter nearly as much as we sometimes like to think they do.  As much as technical testing may be a part of our job in pre-production, what ultimately gets seen and gets us hired again are the images we shoot on set, and if they don’t move people or serve the story well, then who cares what bit depth or codec the source files were?  Just my thoughts.

Best Wishes,

Maxwell Geoffrey
DP | Colorist
New York

On Dec 27, 2020, at 18:00, 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).


Log, or let’s call it in general: input curve, can easily travel as metadata or be applied in edit/viewing environment. There is negligible overhead of doing so. It doesn’t need to be “backed-in”. The size benefit of log raw vs. linear raw is relatively minor.


Compressed raw requires more powerful hardware (GPU), not less. In particular on a notebook. But, Sigma fp offers both compressed formats and uncompressed DNG. You can chose. Compatibility wise: uncompressed Cinema DNG can be readily used in any NLE and workflow tools and it is more compatible than any compressed raw. For example, BRAW is not widely supported on anything but Resolve and even Resolve requires expensive GPU. RED RAW requires decent GPU too.

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.


Kind Regards,


Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”


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