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Re: Sigma fp

Re: Sigma fp


Pawel Achtel, ACS
 

Ø  12-bit raw footage with linear encoding clips harshly, and loses some highlight forgiveness (witness the AJA Cion). Log encoding enables 12-bit raw to deliver quality comparable to what's possible with 16-bit linear encoding, though there are of course some tradeoffs in highlight detail as a result. That's engineering for you; in the end, math and physics win every time.

 

This is incorrect. The sensor reads (in vast majority of cases) 12 bits or 10-bits linear. Only then, it can be converted to from linear to log. To say that 12-bit linear clips harshly and log doesn’t is just nonsense because log originates as 12-bit (or 10-bit) linear and cannot “unclip” signal that is already clipped.

 

Ø  Since there are lossless compression options, IMO uncompressed raw is simply silly. Just imagine the data rates we'd be looking at for 8K 16-bit footage -- never mind 12K, even with the slightly lower 12-bit depth. Uncompressed 8K or 12K would be simply insane.

 

There is no 16-bit sensor in existence: not 8K not 6K not 4K, not any K, so I have no idea what you are talking about. There are (very) few 14-bit attempts with (very) questionable benefits. Most high-end sensors perform either 10-bit or 12-bit AD quantization. There is no useful signal below 12-bits in any sensor that I know. It is just noise.  

And, as you referring to a “12K” example, BMD 12K camera compresses the hell out of the footage to the point that it actually doesn’t resolve even 4K detail. This is, what I would call poor use of bandwidth. Whilst I haven’t compared side-by-side Sigma fp 4K against BMD 12K, my bet would be that the former would resolve higher detail and do so with less bandwidth. It would be an interesting test to perform. Any volunteers?  

 

The beauty of uncompressed RAW is in that it doesn’t require much GPU processing in-camera. Real-time compression uses a lot of power, makes camera bigger at absolutely no benefit to the resulting image quality.

 

The reality is that uncompressed and unprocessed RAW can be much better treated in post with much higher degree of control. One of those things is noise reduction. Noise reduction applied at uncompressed RAW produces much better results (in terms of effectiveness as well as preserving detail) than it does after footage has been processed or compressed.

 

Ø  Again, there is zero value in uncompressed raw in this day and age.      

If you do not care about image quality, compression artefacts, dynamic range, noise and sharpness, sure, it may present zero value to you. Sigma fp has compressed recording options too for those that still use floppy discs. J

To me uncompressed RAW offers (by far) the best workflow possible with most options, control and preserving the highest image quality possible.

 

Kind Regards,

 

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

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

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From: cml-raw-log-hdr@... [mailto:cml-raw-log-hdr@...] On Behalf Of Rakesh Malik
Sent: Sunday, 27 December 2020 2:44 PM
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] Sigma fp

 

12-bit raw footage with linear encoding clips harshly, and loses some highlight forgiveness (witness the AJA Cion). Log encoding enables 12-bit raw to deliver quality comparable to what's possible with 16-bit linear encoding, though there are of course some tradeoffs in highlight detail as a result. That's engineering for you; in the end, math and physics win every time.

 

More important however is that there are a lot of workflows where ANY flavor of raw is overkill, and for those clients tend to favor codecs like ProRes, and for those log encoding is a big help.

 

Since there are lossless compression options, IMO uncompressed raw is simply silly. Just imagine the data rates we'd be looking at for 8K 16-bit footage -- never mind 12K, even with the slightly lower 12-bit depth. Uncompressed 8K or 12K would be simply insane.

 

Black Magic added lossless compressed cDNG to its first Pocket cinema camera, and it made a huge difference in data rates -- but being lossless, it has no effect on the data itself.

 

Again, there is zero value in uncompressed raw in this day and age.

-----------------------------

 

 

Rakesh Malik

about.me/WhiteCranePhoto

Director of Photography, Colorist

 

 

 

 

On Sat, Dec 26, 2020 at 7:28 PM Pawel Achtel ACS <pawel.achtel@...> wrote:

Ø  I like having a raw option, but I don't see any point in uncompressed raw. It's a waste of space

 

So, how much do you save with Log? 2 bits (20%)?

Do you prefer compression artefacts, instead? Again, in my experience, images from Sigma fp are actually cleaner and with less artefacts than that of many (most) high-end digital cinema cameras. This camera punches way above its weight and I would not hesitate to use it as A-camera on A-grade movie.

 

Ø  Uncompressed RAW has been available for well over a decade on major camera systems and devices I’ve been directly involved with. The vast majority of people who owned these or considered owning them hated the workflow and often did workarounds to avoid it.

 

Mitch, as you said: this was a decade ago. J Storage has increased dramatically in size and speed since then. I think 370MB/s is very reasonable and not that much higher than Log and/or compressed formats. What is, however compelling about uncompressed RAW is that it is less processed, richer and more forgivable format. To me it is an advantage, not drawback. It is upstream from Log or compressed formats. You can always create a Log from it or/and compress it if space is an issue.

 

Kind Regards,

 

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

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 

From: cml-raw-log-hdr@... [mailto:cml-raw-log-hdr@...] On Behalf Of Mitch Gross
Sent: Sunday, 27 December 2020 1:27 PM
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] Sigma fp

 

Because uncompressed RAW means huge files that take up a lot of disk space, take a lot of time to transfer, and require considerable computer power to deal with. But with Log encoding you get the vast majority of flexibility in what the sensor can capture but recorded in a data scale that is reasonable enough to everyone to work with. Clients won’t complain about the data load and the work can happen quickly and effectively. 

 

Uncompressed RAW has been available for well over a decade on major camera systems and devices I’ve been directly involved with. The vast majority of people who owned these or considered owning them hated the workflow and often did workarounds to avoid it. When reasonably compressed Log recording became available to these same devices their popularity skyrocketed. It has happened numerous times. 

 

DPs who don’t have to care about workflow want uncompressed RAW. DPs shooting for the highest level productions want uncompressed RAW. I understand that. But they comprise an infinitesimal percentage of actual users. Most people want the advantages of capturing all that dynamic range while not having the burden of uncompressed RAW workflow. For a petite and inexpensive camera such as the Sigma FP I would argue that the vast majority of people considering its use, compressed Log video is far more attractive than uncompressed RAW. 

Mitch Gross

New York

 

On Dec 26, 2020, at 6:46 PM, Pawel Achtel ACS <pawel.achtel@...> wrote:

[Mitch Gross] I would expect that Log encoding is more useful to a vast number of CMLers and DPs in general than Uncompressed RAW recording.

Why?

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