Canon's logarithmic gamma curve preserving maximum dynamic range for color grading.
Technical Details
C-Log operates with a gamma curve of 0.45, shifting the 18% gray tone to 32.8% of the video signal. The current version, C-Log3, captures a dynamic range exceeding 1600% (equivalent to 14+ stops) while utilizing the BT.2020 color space. C-Log2, as a compromise variant, offers 12 stops with improved noise characteristics in the shadows. The profile reduces contrast to approximately 1:1.2 (compared to 1:100 for standard profiles) and lowers color saturation by about 60% to preserve maximum image information.
History & Development
Canon introduced C-Log in 2012 with the EOS C300, inspired by Kodak's Cineon Log format from the 1990s. In 2014, it was integrated into DSLRs starting with the EOS 5D Mark III via firmware update. C-Log2 debuted in 2016 with the C700 series, and C-Log3 arrived in 2018 with the EOS R series. The development aimed to digitally reproduce the grading potential of Super-35mm film while ensuring compatibility with established post-production workflows.
Practical Use in Film
Series like "House of Cards" (Season 6) and "The Crown" utilize C-Log for consistent color correction across different lighting conditions. The typical workflow involves recording in C-Log, applying a LUT (Look-Up Table) for set monitoring, and final color grading with specific C-Log-to-Rec.709 LUTs. Advantage: 2-3 additional stops in highlights and shadows. Disadvantage: Mandatory post-production and 10-15% larger file size compared to standard profiles.
Comparison & Alternatives
C-Log directly competes with Sony S-Log (14+ stops), Panasonic V-Log (12+ stops), and RED R3D-Log. While S-Log works more aggressively in the shadows, C-Log exhibits more natural skin tones without extensive correction. For budget productions, standard profiles with manual contrast reduction offer 80% of C-Log's benefits with direct usability. C-Log is primarily suited for high-end productions with professional post-production, while standard profiles suffice for broadcast or online content without complex lighting setups.