S-Gamut3 or S-Gamut3.Cine?

We’ve written extensively about the benefits of shooting RAW but once you’ve picked up your Ninja V, you might still be wondering which color space to use.

For HDR acquisition, we recommend:

Format

  • ProRes RAW HQ or ProRes RAW

Quantization

  • 16-bit linear

OETF

  • S-Log3

Color Space

  • S-Gamut3 or S-Gamut3.cine

Dolby writes, “Where content is going to be color graded, it is recommended to use source material that best retains the native color gamut and original dynamic range of the content at the time of its origination in order to create high quality Dolby Vision content”. S-Gamut3 is nearly camera native color space, which meets Dolby’s criteria and it would appear to be ideal for ACES and ITU-R BT.2020. Whether the sensor in the a7s III can even see the full color range that S-Gamut3 is capable of recording is another story altogether. When recording ProRes RAW, the camera is capturing sensor native data and no color space or log curve is applied – only the color space metadata is saved. The color space is applied to the RAW data during the de-Bayer process, so perhaps it’s not a life or death matter which of the two gamuts we choose for recording – but which one is optimal for HDR grading isn’t entirely clear. What do DPs shooting Netflix Originals prefer? The Camera Production Guides that spell out the settings and best-practices for capture with Sony cameras on Netflix 4K Originals from the Venice on down, whether XAVC or RAW, recommend either S-Gamut3/S-Log3 or S-Gamut3.cine/S-Log3, adding that S-Gamut3.cine/S-Log3 is the most common color space used on FX9, F55, FS7, F5 and FX6 productions. We’ve also been informed that key mastering engineers at Sony Pictures in Culver City recommend selecting the S-Gamut3.cine/S-Log 3 settings in Resolve. As for S-Log3, it is recorded as full range and there is no option to select legal range. RAW video is recorded as 16-bit linear which is then compressed and recorded in the Ninja V as 12-bit ProRes RAW.

Note: Virtually every custom LUT developed for Sony S-Log3 is for S-Gamut3.Cine, including those created by Technicolor and Picture Shop in collaboration with Sony for their flagship cinema cameras, the Venice and Venice 2, so that might be something to consider when deciding which gamut to shoot.

Art Adams had this to say about choosing gamut:

“While the temptation to use full SGamut3 is probably overwhelming to some, it’s best to ask yourself (1) when will the extra color be displayable, (2) will your project still be marketable when that happens, (3) are you shooting anything that takes advantage of that color space, and (4) do you have the talents of a professional and expert colorist at your disposal. If not, SGamut3.cine is clearly the better choice. If your project has a long shelf life and would look great with rich saturated color then SGamut3 will protect all that, but you won’t be doing the Rec 709 or P3 grades yourself: you’ll need skilled professional help.”

Then there’s this advice from Sony Professional:

”There is a lot of confusion regarding S-Gamut3 and S-Gamut3.Cine. Essentially the difference is S-Gamut3 is the native (very wide) color space of the camera, and is wider than REC-2020. It is very good for archiving as a digital camera negative, as transcoded / debayered up to16 bit code values. However, it is much more involved to grade footage than if shot using S-Gamut3.Cine. Whereas S-Gamut3.Cine is natural color reproduction with minimum grading needed in comparison to SGamut3, it is still a wide color space, beyond DCI-P3, and much wider than REC-709. We recommend shooting S-Gamut3.Cine most of the time. The Look Profiles, and 709 3DLUT’s provided in the camera, and in Sony’s RAW Viewer are designed specifically for S-Gamut3.Cine, not for S-Gamut3. If you choose to shoot S-Gamut3 you need to convert to S-Gamut3.Cine with the 3DLUT provided below, “SLog3SG3toSG3Cine.cube”, then in addition apply Look Profiles or other type 3DLUT provided with the camera and in Sony’s RAW Viewer. In other words you need to apply two 3DLUT’s. If you are experienced at Color Grading, you can indeed shoot S-Gamut3, but as mentioned above it is much more work than if shooting (and thus grading) S-Gamut3.Cine”.

Lastly, here’s a comparison between S-Gamut3 and S-Gamut3.Cine with color correction.

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