Log and negative film stock

[Robin R Probyn]

Tyler says that S-log is flatter than film negative, not that S-Log = RAW.

 

 

 

' MPEG based cameras have created a "FAUX" Raw format called S-Log."

 

Thats what he says.. seems pretty plain to me .. Slog is a Faux RAW.. its not.. its LOG ? its wrong info.. When is Sony ever saying Slog is anything but Log.. Is Arri LogC "fake " RAW?

Edited April 6, 2016 by Robin R Probyn

[Robin R Probyn]

That's right and nowhere did I say slog is raw. The word "faux" means fake.

 

Slog was developed specifically for cameras that don't record raw and record to rec709. If you shoot raw you don't need slog curve, it's irrelevant in fact.

 

Ohh and we've already had discussions on cameras that need special hardware to record properly. Most people won't invest unless it's necessary. In the case of the OPs question, film has no relationship to camera raw or slog.

 

 

 

Wrong again.. F5/55 65 all can record RAW. . even the Fs7..

Edited April 6, 2016 by Robin R Probyn

[Robin R Probyn]

"You will notice, S-Log is used on cameras that shoot MPEG. Cameras that DON'T shoot MPEG... Arri, RED, Blackmagic, AJA, don't have S-Log because they don't need it. "

 

Now I really wonder if you are not taking the piss and having a good laugh.. I sort of hope so in a way.. Slog is a Sony gamma.. guess what.. thats why its in Sony Camera,s..!! as Ive tried to tell you.. Arri LogC is very much the same as SLog3.. as is the AJA Cineon .. sorry man you really have no clue about Slog.. or LOG at all it seems..

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[Robin R Probyn]

 

 

Has nothing to do with MPEG compression though, just the limitations of 10-bit recording.

 

S-Log was not developed to deal with MPEG compression. It first appeared as a copy of Panavision Genesis' PanaLog but in the Sony F35, both of which recorded to HDCAM-SR tape in 10-bit 4:4:4 or 4:2:2 using a fairly mild MPEG compression scheme. PanaLog and S-Log were created to store dynamic range in a form closer to the 10-bit Cineon Log format that D.I. colorists were used to working with from film scans. They were fairly mild Log gamma curves because the cameras only generated about 12-stops of dynamic range (which is one reason why Canon's C-Log is also fairly mild.) You could get similar dynamic range using a different gamma curve like Hypergamma but it wouldn't have had the headroom range of Log, which puts white on an 1-step grey scale at something like 70 IRE in order to record a couple of stops of overexposure detail. Hypergamma curves didn't place white so low though you could have done that by underexposing. But the shape of the Hypergamma curve was also different than with Log.

 

S-Log is just a gamma curve, it could be recorded uncompressed, it could be recorded at 16-bits, RGB, YUV, 4:4:4, 4:2:2, whatever... it has nothing to do with MPEG compression. That's not why it exists. It exists to fall into the log workflows leftover from film's D.I. color-correction days and the colorists who are used to working with images that way. It exists to fit 12 to 15 stops of dynamic range into 10-bits, which again, has nothing to do with compression, you can have 10-bit uncompressed recording.

 

 

Ok now you heard it from someone who really knows what they're talking about.. not just my rantings :).. again.. please read up a bit about digital codec,s before you give duff advise .. over and out..

Edited April 6, 2016 by Robin R Probyn

[Robin R Probyn]

"That's right, S-Log is it's own LOG curve, incompatible with every other system and looks nothing like real LOG, which even looks nothing like color negative."

 

What are you talking about ? what is REAL LOG.. how is SLOG not real LOG..have you even seen it as a plotted curve.. do you know what Arri LOG C looks like.. your really going down the rabbit hole with this stuff now..

[Tyler Purcell]

Sounds to me like your real beef is with the implementation of log on the lower end camera systems. Again, S-Log/2/3 were intended for use on F23/35/65/55/5 with their 10/12/16-bit recording systems. Everything else was an unintentional bonus.

Actually the use of LOG was used way before those cameras were even contemplated.

 

S-Log in of itself is a way to compress the imagers data into a 8 or 10 bit package. Again, an "inferior" package because the end result is nowhere even close to the imagers actual dynamic range.

 

12, 14, 16 bit RAW capture is LINEAR not LOG. Sure you can apply a LOG curve to anything you want, but the imager is absolutely linear.

 

The point I was trying to make in my original clearly "offensive" but in my eyes, completely accurate statement is that Sony's S-Log format only exists due to the inferior camera recording formats.

This log graph shows the different formats compared to "ACES" which is liner.

 

 

This graph shows the lack of dynamic range with S-Log compared to Log C from the Alexa recorded in PRO RES... NOT RAW.

 

 

Clearly the Pro Res is greater dynamic range then the MPEG of the S-Log and C-Log cameras.

[Satsuki Murashige]

Actually the use of LOG was used way before those cameras were even contemplated.

 

Dude. From upthread:

< Log was created as a means of capturing the full dynamic range of the negative in a film scan to the Kodak Cineon format.>

 

12, 14, 16 bit RAW capture is LINEAR not LOG. Sure you can apply a LOG curve to anything you want, but the imager is absolutely linear.

 

Dude.

<S-Log and its successors were intended for use on cameras recording uncompressed 12-bit video like the F23 and F35. It was an improvement of the Hypergamma curves used on the F900 camcorders.>

 

<Again, S-Log/2/3 were intended for use on F23/35/65/55/5 with their 10/12/16-bit recording systems.>

 

The point I was trying to make in my original clearly "offensive" but in my eyes, completely accurate statement is that Sony's S-Log format only exists due to the inferior camera recording formats.

 

Inferior to what? Raw? S-Log was created for use with uncompressed video formats at a time when the only cameras recording raw were the Red One, Arri D20, and Dalsa Origin. Your choices at the time were either uncompressed raw, highly compressed .r3d files, or uncompressed video encoded with log gamma. The world has moved on since then.

 

In the second graph you posted, the Alexa in Log C shows more dynamic range because the Alexa sensor simply captures more than the Sony F55 sensor. It has nothing to do with Prores vs mpeg or Log C vs SLog3.

[Robin R Probyn]

""That's right, S-Log is it's own LOG curve, incompatible with every other system and looks nothing like real LOG, which even looks nothing like color negative."

 

Tyler.. what is "real Log" and what does it look like.. .. and what systems is Slog incompatible with.. please share..

[Robin R Probyn]

Tyler.. your mixing up Log and Slog.. Slog is a Sony gamma.. thats why its only in Sony camera,s..this is not a big surprise ..its recording are totally compatible with all NLE.. although still you have yet to actually explain what you meant by that comment .. its not in the c300.. neither is XAVC,again a Sony codec.. as you posted earlier..

 

You mix up dynamic range of a sensor.. with gamma curves.. and gamma curves with codec,s.. Slog or any log has nothing to do with MPEG compression..I mentioned this vey early on in this thread.. and you mix up 8 bit and 10 bit.. for the record Log C and Slog 3 are both 14 stop DR..

 

Can you explain what you mean by Slog being .."incompatible with every other system.".and "looks nothing like real Log".. don't go into any other rabbit holes as you usually do .. just explain point blank these two comments you made.. inquiring minds want to know..

Edited April 7, 2016 by Robin R Probyn

[Perry Paolantonio]

Pro Res XQ is the best standard recording format out there today. It actually doesn't work in REC 709, it has far more dynamic range then even the standard Pro Res codec's. I use XQ all the time, mostly to color Alexa shots.

 

The only difference between ProRes 4444XQ and ProRes 4444HQ is bit rate. Both are RGB, but XQ uses less compression than HQ, and in theory that will help with HDR images where there might be more high frequency information that the HQ compression would lop off.

 

The downside is that you can't easily play XQ files on Windows (you have to modify some bits in the Quicktime Header first to trick Quicktime into handling it), and the files are much bigger. On the mac, it only works in Mavericks or newer. I'm not convinced the gain is worth it for day to day use, to be honest. ProRes 4444HQ is a great format, and works in any application that supports ProRes.