Sony F3 SLOG Gemini 4:4:4 grading tests

Over on Filippo Chiesa posted one of the World’s first official Convergent Design Gemini 4:4:4 recorder tests and was also kind enough to make available some of the images from the shoot in DPX format. The footage was shot on the Sony F3 with the S-LOG Gamma option and recorded via dual link to the Gemini recorder in 4:4:4. The actual video itself can be watched here:

S-LOG is not all that new and described in Sony’s 2009 white paper on S-LOG as a “digital negative” which allows maximum tonal reproduction of the camera’s imaging sensor. Since the F3 S-LOG gamma option allows you to enable 4:4:4 out via dual link it has raised a few questions on the true benefit of 4:4:4 over 4:2:2 color sampling. Some are calling 4:4:4 overkill and dismissing the Gemini recorder all together claiming that recording 10-bit 4:2:2 is “good enough”. Others however are certain the true benefits of 4:4:4 aren’t noticeable when simply viewing de-slogged footage, but instead during post production for grading, green screen, and visual F/X work.

One area I’m very interested in is to see how well S-LOG can hold up in its ability to recover detail in the highlights. I’ve been told that it’s WYSIWYG and that S-LOG only improves dynamic range and is not the same as a “RAW” image, but newer test results are showing us that there is in fact some possibility of recovering detail in highlights that may otherwise be lost if blown out. For me at least, this is one of the most powerful aspects of shooting S-LOG if it is the case because for decades when shooting video we’ve struggled to retain detail in highlights and finally now we may have it on a price friendly camera like the Sony F3.

Highlight detail recovery abilities aside, below are some sample grades I performed in post as a result of playing with Philip’s images. The first image shows the image in its flat S-LOG state and the rest show the progression of being de-S-Logged and then finally some subtle color correction and very minor grading. These images were downsized to 1/4 size and yet the detail still stands clear and beautiful.



Grade #1

Grade #2

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