FS7: S - Gamut3Cine V.S. S - Gamut3

Thanks Grug, that's definitly good to know until I actually have the time to understand the technical difference between the two.
 
In in Cine EI you can only use SGamut3.cine with SLog3 and SGamut with Slog2 so it's a moot point really.
 
Liam,

You are correct that SGamut is only available with SLog2, but I believe he is asking about the difference between SGamut3.Cine and SGamut3, both of which are available with SLog3.
 
S-Gamut and S-Gamut3 cover the same basic range of colours - a lot! Seemingly beyond what the F5 and FS7 are capable of resolving, and the reason why the F55 has a different CFA and can claim a wider range. In a recording, the practical consequence is that no matter how insanely vibrant a colour you point the camera at, on an F5 or FS7 in S-Gamut or S-Gamut3 it is not going to reach very far on the vectorscope. A bit like carrying a very large suitcase that you never more than half fill.

With 16-bit raw, not such a big deal, but at 10-bit (or, heaven forbid, 8-bit) when you expand that desaturated look into say colourful Rec709 it's not an efficient spread. Not necessarily bad, but wasteful.

S-Gamut3.cine is meant as a marginally smaller gamut, though still plenty wide enough for most cases (unless you are planning to remake Batman & Robin at a Hindu Festival of Colours ;-) ). The F5 and FS7 will fill it better, making better use of the recording range. The relationship between the primaries is also closer to a display look so is supposed to be less work to tart up into a finished product in post.

As for the difference between S-Gamut3 and S-Gamut, that's mentioned in the technical note linked to earlier and is, well, technical ;-). I could very well be wrong in my interpretation, but I'm reasonably confident it's not too far off the mark. If you are still interested, here be dragons:

In general with 'proper' log recording conversion from one colour space to another could be done through a transfer function (the equation representing what people tend to call the log gamma curve) to scene linear, followed by a simple (3x3) matrix operation to convert from one gamut to another then finally followed by a transfer function to the destination 'gamma'. In ACES the IDT performs the first two of those operations, as ACES works internally on linear data.

Sometimes - such as with the C300 which is designed to be simple, 8-bit and look nice without worrying too much about flexibility - the gamut part is more complex, but with S-Log/S-Gamut variants, LogC/Arri Wide Gamut and even Canon C-Log/Cinema Gamut on the C500 the simple 3x3 conversion holds true.

The thing is that the actual parameters in that matrix tend to change with colour temperature. Again, looking to ACES, there are different matrices for tungsten and below and for around daylight in relation to S-Gamut. The difference tends to be subtle, but there and if mixing cameras in an ACES workflow or correcting faults potentially important to factor.

So far so good, but this next bit is my interpretation of the technical note:

As I understand it, S-Gamut3 covers exactly the same basic gamut or range of colours as S-Gamut, but is explicitly designed to use the same conversion values at all colour temperatures. Makes consistency simpler, and should make it very amenable to LUTs and for a simple ACES IDT,

Ben
 
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cameramanben said:
S-Gamut3.cine is meant as a marginally smaller gamut, though still plenty wide enough for most cases (unless you are planning to remake Batman & Robin at a Hindu Festival of Colours ;-) ). The F5 and FS7 will fill it better, making better use of the recording range. The relationship between the primaries is also closer to a display look so is supposed to be less work to tart up into a finished product in post.
Click to expand...
This is the important point here.

S-Gamut and S-Gamut3 are designed to contain all the colour a camera can capture, and in order to do so have widely spaced red, green and blue primaries which do not line up with the Rec.709 primaries in terms of hue angle on a vector-scope*. So just adding an s-curve and some saturation will not be enough to make a good looking image from an S-Log3/S-Gamut3 one. You need a colour matrix, or a LUT which incorporates a matrix transform.

S-Gamut3.Cine, on the other hand, is a slight compromise for the sake of simplicity for the user. It can't contain every colour a camera may capture, but it contains most of them. And because the primaries line up more closely on a vector-scope with the hues of Rec.709 primaries, you can get a reasonable looking image from an S-Log3/S-Gamut3.Cine one just with an s-curve and a saturation boost.

*Hue angle on a vector-scope is not strictly accurate, but it's a good way of visualising what I am talking about.
 
Nick, that is the best, most concise explanation I've seen. Please save a copy and post it when this comes up again . . . and again.
 
Curveo's link to Sony's post is words directly from the horses mouth. http://community.sony.com/t5/F5-F55/S-Gamut3-vs-S-Gamut3-Cine/m-p/446476

This picture helps put things in perspective:

ScreenShot2015-01-20at44128PM_zps1b71ab7e.png


Sgamut and Sgamut3 are the widest, likely only the F55 can utilize it because of the CFA.

One crux here is that Sgamut is the color space in CUSTOM mode, and Sgamut3/Sgamut3.cine is available in CineEI mode. The Sgamut3.cine is easiest and fastest to grade, footage shot in CUSTOM mode which gets stuck with Sgamut color science, tends to get that "Sony" or "nuclear color" look.

For those really wanting to wrap their head around color space and color science of the Sony cameras, although I do hate chart shooting, I did do some extensive tests shooting a color chart in the various modes to see how they differ. I also played around with some MATRIX presets in Custom mode which are suppose to simulate the color science of those available in CineEI mode! (those matrix presets only available on the F55 unfortunately)

That first test and downloadable charts are available on DVINFO in an article of mine that they published; http://www.dvinfo.net/article/acqui...ng-cineei-mode-in-custom-mode-on-the-f55.html

As well I did a follow up to this test by then taking Sony's very two distinct set of 3D LUTS (one set meant for Sgamut/custom mode, and one set meant for Sgamut3.cine) and applying them to the respective color chart shot in the color science they were intended for to see how close they would look to one another. The short of it was that even by using the correct 3D LUT from Sony on footage shot in Custom Mode and CineEI mode, the results were different in color. I would have thought that LC709A from each respective camera mode would net out to the same color, nope.

Here is a link to that follow up article and results: http://www.hingsberg.com/index.php/2015/04/sony-3d-luts-test/
 
Ahhhh Dennis....
I think most posters in here really don't grok the technical details. They'd rather moan and fantasize, rather than understand. And those with the actual facts are passed over like yesterday's newspaper. 99% of the posts in here are opinions...not facts. Which points out that these are "opinion boards". Anything one reads in here needs to be taken with a huge glass of doubt.
 
This was great, and easily digested. Great explanation.

starcentral said:
Curveo's link to Sony's post is words directly from the horses mouth. http://community.sony.com/t5/F5-F55/S-Gamut3-vs-S-Gamut3-Cine/m-p/446476

This picture helps put things in perspective:

ScreenShot2015-01-20at44128PM_zps1b71ab7e.png


Sgamut and Sgamut3 are the widest, likely only the F55 can utilize it because of the CFA.

One crux here is that Sgamut is the color space in CUSTOM mode, and Sgamut3/Sgamut3.cine is available in CineEI mode. The Sgamut3.cine is easiest and fastest to grade, footage shot in CUSTOM mode which gets stuck with Sgamut color science, tends to get that "Sony" or "nuclear color" look.

For those really wanting to wrap their head around color space and color science of the Sony cameras, although I do hate chart shooting, I did do some extensive tests shooting a color chart in the various modes to see how they differ. I also played around with some MATRIX presets in Custom mode which are suppose to simulate the color science of those available in CineEI mode! (those matrix presets only available on the F55 unfortunately)

That first test and downloadable charts are available on DVINFO in an article of mine that they published; http://www.dvinfo.net/article/acqui...ng-cineei-mode-in-custom-mode-on-the-f55.html

As well I did a follow up to this test by then taking Sony's very two distinct set of 3D LUTS (one set meant for Sgamut/custom mode, and one set meant for Sgamut3.cine) and applying them to the respective color chart shot in the color science they were intended for to see how close they would look to one another. The short of it was that even by using the correct 3D LUT from Sony on footage shot in Custom Mode and CineEI mode, the results were different in color. I would have thought that LC709A from each respective camera mode would net out to the same color, nope.

Here is a link to that follow up article and results: http://www.hingsberg.com/index.php/2015/04/sony-3d-luts-test/
Click to expand...
 
Glad you found it understandable and easy to digest.

The basic take away is you will never get the same look from either mode easily, and for that I am seriously hoping Sony does something to address this in future firmware.

It causes other issues for camera operators when they want to chose custom mode because they want the ability to custom white balance for example. Tons of rants about this on the forums.

Too much confusion with the Sony cams, really they should make all 3 color spaces available in any mode, or just get rid of the original sgamut (although getting rid of it is likely to upset some folk)

cheers,
 
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