Professional Color Grading Workflow for Sony S-Log3 and S-Gamut3.Cine Footage in DaVinci Resolve

DaVinci Resolve Tutoriais

Summary:

Color Grading Sony Footage: This tutorial explains how to professionally color grade Sony S-Log2/S-Log3 footage in DaVinci Resolve.
Understanding Color Space & Gamma: It emphasizes the critical importance of knowing the footage's specific color space (e.g., S-Gamut3.Cine) and gamma curve (e.g., S-Log3), distinguishing them from camera presets (like PP7 or PP6).
Recommended Sony Settings: For optimal quality, S-Log3 and S-Gamut3.Cine are the recommended settings, though S-Log2 might be better for 8-bit footage due to shadows.
Common Mistake: Directly applying contrast and saturation to flat log footage is a major error, as it discards valuable image information.
Professional Workflow with CST: The correct approach involves using the Color Space Transform (CST) tool in DaVinci Resolve to convert log footage (S-Gamut3.Cine/S-Log3) to a display-referred standard (Rec.709 Gamma 2.4).
Correction Placement: Primary color corrections (exposure, white balance) should be done before the CST node to utilize the full dynamic range of the log footage.
Creative Grading: After the technical transform, creative LUTs can be applied to achieve desired looks. It's crucial to use LUTs designed for the correct color space (e.g., Rec.709).
Benefits: This workflow ensures maximum image quality, professional results, and efficient creative control.

Introduction to Sony Color Grading [0:27]

This tutorial targets users of Sony cameras (a7S, a7IV, FX3, ZV-E1, ZV-E10, etc.) who film in S-Log2 or S-Log3.
The video's main goal is to teach a professional color grading workflow, highlight common mistakes, and provide practical tips for maximizing the quality of Sony footage.

Understanding Color Space and Gamma Curves [1:01]

Footage Examples:
- The presenter uses sample footage from a Sony FX3 (basketball scene) and a Sony a7SIII (surfing scene).
Relevance Across Sony Models:
- It's noted that the image science, sensor characteristics, color space, and gamma configurations are consistent across different Sony camera models.
- Therefore, the grading process remains largely the same, regardless of the specific Sony camera model (e.g., high-end vs. entry-level).
Essential Information for Grading:
- Identify Camera Settings: The most crucial piece of information is knowing which color space and gamma curve were used during recording.
  - How to Find This: Users should check their camera's menu for these settings. If unsure, online resources like Google, YouTube, or even ChatGPT can provide quick tutorials on configuring color space for specific camera models.
- Recommended Sony Settings:
  - Sony generally recommends using S-Log3 and S-Gamut3.Cine for optimal sensor utilization, dynamic range, and color gamut.
  - Bit Depth Considerations: For cameras recording in 8-bit, S-Log2 might be a preferable option as it is less aggressive with shadow details compared to S-Log3, which is better suited for 10-bit or higher recordings.
Clarifying Presets (PP7, PP6, PP Off) [3:18]:
- These are camera presets, not actual color spaces.
- Behind each preset lies a specific configuration of color space and gamma (e.g., Rec.709, S-Log3, S-Gamut).
- It's the underlying technical configuration that matters for color grading, not the preset name itself.

Common Color Grading Mistakes [4:29]

Direct Adjustment of Log Footage:
- The most common error is directly applying contrast, saturation, and other adjustments to "flat" log footage.
- This approach is often taught in unverified online tutorials, leading to suboptimal results.
Why Direct Adjustment is Incorrect:
- Loss of Quality: Directly manipulating log footage (which is designed to capture a wide range of information) without proper transformation leads to a significant loss of potential image quality. It essentially "burns" the data.
- Non-Professional Workflow: This method does not align with the professional color grading workflows used by top colorists.
Technical Explanation (Visual Reference: Color Gamut and Log Curves) [6:31]:
- Display Color Space:
  - Most monitors, TVs, and mobile devices (around 99%) display images within the Rec.709 color space (represented by a smaller triangle in the CIE 1931 chromaticity diagram shown at [6:31]).
  - This is a standardized convention for consistent image display across various screens.
- Camera Color Space (S-Gamut3.Cine):
  - Professional cameras, like Sony's with S-Gamut3.Cine, capture a much wider range of colors (a larger triangle/gamut in the diagram at [7:50]) than standard displays can show.
- Gamma Curves (Log Encoding Curves):
  - S-Log (e.g., S-Log3) dictates how the camera's sensor records luminance information. It compresses the dynamic range into a flat curve to maximize detail retention in highlights and shadows (visualized at [9:40]).
  - This "flat" appearance in log footage is a consequence of these technical specifications, not a flaw to be "fixed" with simple contrast adjustments.
- The Problem: Directly adjusting log footage ignores the underlying technical differences in color space and gamma, failing to properly map the rich camera data to the display's capabilities. It's like trying to "develop" unrevealed film (log) without the correct chemical process, leading to a suboptimal final image.

Professional Workflow: Color Space Transform (CST) [10:20]

Purpose of CST:
- The goal is to accurately transform the image from the camera's native color space and gamma (scene-referred) to a standard display color space and gamma (display-referred) that monitors can properly interpret.
- This mathematical transformation, provided by camera manufacturers, ensures that the maximum quality is retained and correctly represented.
- The term "revealing the log" is used, drawing a parallel to developing photographic film in a lab.
Using Color Space Transform (CST) in DaVinci Resolve [12:01]:
- Locate the "Color Space Transform" effect in the Effects Library.
- Input Settings:
  - Set "Input Color Space" to Sony S-Gamut3.Cine.
  - Set "Input Gamma" to Sony S-Log3.
- Output Settings:
  - Set "Output Color Space" to Rec.709.
  - Set "Output Gamma" to Gamma 2.4 (standard for most monitors).
- Immediate Result: Applying these settings instantly transforms the flat log image into a vibrant, correctly contrasted image suitable for display, without any manual contrast or saturation adjustments.
Correction Placement: Before CST [15:18]:
- Crucial Step: Any primary corrections (e.g., exposure adjustments for images that are too dark or too bright) must be performed in a node before the CST node.
- Why: Working on the log footage before the transform allows you to manipulate the full dynamic range captured by the camera. Adjusting after the CST means you're working on an already compressed and transformed image, limiting your control and potentially degrading quality.
- Troubleshooting: If, after applying CST, the image still appears too dark or bright, it indicates an exposure error during filming, which should be corrected in a preceding node.

Creative Grading with LUTs (after CST) [17:35]

Applying LUTs for Creative Looks:
- Once the technical transform via CST is complete, you can apply creative LUTs (Look Up Tables) in a node after the CST node.
- Demonstration: The presenter demonstrates applying a "Split Tone" LUT from his "LUT Lab" pack to the transformed basketball scene [18:50].
- Result: The LUT quickly applies a stylized look, enhancing the image's aesthetic with ease.
Important Considerations for LUTs:
- LUT Specificity: Each LUT is designed to be applied to footage in a specific color space and gamma. Applying a LUT meant for log footage onto Rec.709 footage (or vice-versa) will produce incorrect or undesirable results.
- Beyond Basic Application: There are advanced techniques for working with LUTs, such as combining multiple LUTs, using them for specific colors or contrast adjustments, and leveraging blending modes.
- Professional Resources: Access to high-quality LUTs and proper training on their advanced application can significantly enhance your color grading capabilities.