What the CST node does
Cameras record LOG to fit more of the range from dark to bright into the file, which is why the image looks flat until it is converted. The CST node reads each color with the log formula of the camera profile you pick, turns it into linear light, applies exposure, then applies the Rec.709 gamma curve.
Before the Rec.709 curve there is a highlight roll-off. Values above the roll-off point are eased down, so very bright highlights do not clip hard. The whole calculation is baked into a 33×33×33 3D LUT and rendered through the FFmpeg lut3d filter on your computer, like the other color nodes.
Supported profiles and how to choose
The Camera (log) dropdown lists Sony S-Log3, Panasonic V-Log, Canon Log, Apple Log and ARRI LogC3. Pick the same profile you recorded with. With the wrong one, contrast and skin tones look off right away. Check the waveform in the right panel to see whether shadows and highlights sit in a sensible range.
Canon Log here is the original Canon Log. Other profiles, such as Canon Log 2 or 3, S-Log2, F-Log, D-Log or LogC4, are not in the list yet. For those, download the official .cube LUT from the camera maker and load it in a LUT node, then grade as usual.
Limits to know
HookWise's CST converts the log curve to Rec.709 gamma. The camera's color gamut, such as S-Gamut3 or V-Gamut, is not mapped to the Rec.709 gamut as a separate step. Colors can look slightly less saturated or shifted, so add a Primary or HSL node after CST, or use the camera's official LUT when you need exact color.
The grade is processed in 8-bit RGB per channel, and the result is SDR Rec.709 video. HDR grading and Rec.2020 output are not available yet. If you push LOG footage hard, check skies and plain walls for banding before you export.
