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Explanation of Gamma Transfer 1D LUT (1D Look-Up Table) and Gamut / Gamma Transfer 3D LUT (3D Look-Up Table) for cameras.

Article ID: ART170391 | Date published: 05/18/2018 | Date last updated: 06/21/2019
 

Description

Explanation of Gamma Transfer 1D LUT (1D Look-Up Table) and Gamut / Gamma Transfer 3D LUT (3D Look-Up Table) for EOS C700, EOS C300 Mark II, EOS C200, EOS C300, EOS C100 Mark II, EOS C100, ME20F-SH, ME200S-SH, XC10, XC15, and XF705

Solution

Gamma Transfer 1D LUT (1D Look-Up Table, Version 2.2
  • LUT Category
    Viewing LUT
 
  • LUT Overview
    A 1D LUT that converts from Canon Log / Canon Log 2 / Canon Log 3 gamma
 
  • File Format
    .cube format
 
  • Applicable Models
    Different 1D LUTs are used because different products have different gamma settings.
    Check the correspondence table below before use.

    [Group 1]
    EOS C700, EOS C300 Mark II, EOS C200

    [Group 2]
    EOS C300, EOS C100 Mark II, EOS C100, ME20F-SH, ME200S-SH, XC10, XC15

    [Group 3]
    XF705
 
  • Correspondence Table
Input Output Group
Gamma Range Bits Gamma Range 1 2 3
Canon Log Full 10/12/2016 BT.709 (Gamma
2.2)		 Full,
Narrow		 ✔ ✔  
Canon Log Full 10/12/2016 Wide DR Full,
Narrow		 ✔ ✔  
Canon Log Full 10/12/2016 Cineon Full ✔ ✔  
Canon Log Full 10/12/2016 DCI (Gamma 2.6) Full ✔ ✔  
Canon Log Full 10/12/2016 Linear Linear ✔ ✔  
Canon Log 2 Full 10/12/2016 BT.709 (Gamma
2.2)		 Full,
Narrow		 ✔    
Canon Log 2 Full 10/12/2016 Wide DR Full,
Narrow		 ✔    
Canon Log 2 Full 10/12/2016 PQ Full,
Narrow		 ✔    
Canon Log 2 Full 10/12/2016 HLG Full,
Narrow		 ✔    
Canon Log 2 Full 10/12/2016 Cineon Full ✔    
Canon Log 2 Full 10/12/2016 DCI (Gamma 2.6) Full ✔    
Canon Log 2 Full 10/12/2016 Canon Log 3 Full ✔    
Canon Log 2 Full 10/12/2016 Linear Linear ✔    
Canon Log 3 Full 10/12/2016 BT.709 (Gamma
2.2)		 Full,
Narrow		 ✔   ✔
Canon Log 3 Full 10/12/2016 Wide DR Full,
Narrow		 ✔   ✔
Canon Log 3 Full 10/12/2016 PQ Full,
Narrow		 ✔   ✔
Canon Log 3 Full 10/12/2016 HLG Full,
Narrow		 ✔   ✔
Canon Log 3 Full 10/12/2016 Cineon Full ✔   ✔
Canon Log 3 Full 10/12/2016 DCI (Gamma 2.6) Full ✔   ✔
Canon Log 3 Full 10/12/2016 Linear Linear ✔   ✔
  • File naming convention
    [Gamma]_[BitNum]-to-[Gamma]_[Range][Range]_[Version].cube
         (1)           (2)                (3)            (4)        (5)          (6)
  • Example:CanonLog_10-to-BT709_FF_Ver.2.0.cube
  1. Input gamma
  2. Input bit depth
  3. Output gamma
  4. Input range (N: Narrow, F: Full)
  5. Output range (N: Narrow, F: Full, L: Linear)
  6. Version
  • Explanation of the data format
    Example: Canon Log 2 to Cineon 10-bit version
     
    Lines beginning with the pound sign (#) Comments about the 1D LUT file
    LUT_1D_SIZE_1024 Size of the 1D LUT
     
    0.000000 0.000000 0.000000
    0.000510 0.000510 0.000510
    0.001728 0.001728 0.001728
    0.002946 0.002946 0.002946

     
  • Explanation of Linear LUTs
    -0.016363 -0.016363. -0.016363            Indicates the data are Scene Linear values
    -0.016298 -0.016298 -0.016298   Example: 0.200000 = 20% (18% Grey)
    -0.016234 -0.016234 -0.016234   1.000000 = 100% (90% White)
    -0.016169 -0.016169 -0.016169    

     
  • LUTs for conversions to Wide DR
    The Narrow range version of Wide DR is a curve that was used into the super-whites
    (outputs over 100%), whereas with the Full range version of Wide DR, this curve is
    compressed in a format to fit within 100% output.
     
  • Nominal signal levels of conversion LUT from Canon Log 2/3 to PQ/HLG
    These LUT are used to convert to the perceptual quantization (PQ) and Hybrid Log-Gamma (HLG) defined by Recommendation ITU-R BT.2100-2.
    Conversion is performed to achieve the signal levels described in TABLE 1 of Report ITU-R BT.2408-1.

     
  • Reference: Gamma data values at different brightnesses
    Gamma Range Scene Linear % (Reflection %)
    0%
    (0% Black)    		 20%
    (18% Grey)    		 100%
    (90% White)    		 800% 1600% 6400%
    Canon Log Full 0.1251 0.3434 0.5998 0.9929  -   - 
    Canon Log 2 Full 0.0929 0.3983 0.5623 0.7792 0.8518 0.9971
    Canon Log 3 Full 0.1251 0.3434 0.5645 0.8872 0.9971  - 
    Cineon Full 0.0928 0.4697 0.6691 0.9325  -   - 
    DCI
    (Gamma 2.6)    		 Full 0.0000 0.4622 0.7938 1.0000  -   - 
    Wide DR Full 0.0000 0.3963 0.7294 0.9927  -   - 
    Narrow 0.0625 0.4340 0.7463 0.9931  -   - 
    BT.709
    (Gamma 2.2)    		 Full 0.0000 0.4337 1.0000  -   -   - 
    Narrow 0.0625 0.4336 0.9182  -   -   - 
    PQ Full 0.0000 0.3790 0.5679 0.8216 0.9048 -
    Narrow 0.0625 0.3868 0.5485 0.7655 0.8367 0.9734
    HLG Full 0.0000 0.3781 0.7291 - - -
    Narrow 0.0625 0.3861 0.6864 - - -


Gamut / Gamma Transfer 3D LUT (3D Look-Up Table), Version 1.1
  • LUT Category
    Viewing LUT
     
  • LUT Overview
    A 3D LUT that converts from Cinema Gamut / DCI-P3 Gamut / BT.2020 Gamut / BT.709 Gamut and Canon Log / Canon Log 2 / Canon Log 3
     
  • File format
    .cube format
     
  • Applicable Models
    Different 3D LUTs are used because different products have different gamma settings.
    Check the correspondence table below before use.

    [Group 1]
    EOS C700, EOS C300 Mark II, EOS C200

    [Group 2]
    EOS C300, EOS C100 Mark II, EOS C100, ME20F-SH, ME200S-SH, XC10, XC15

    [Group 3]
    XF705
     
  • Correspondence Table
Input Output Applicable Group
Gamut Gamma Range Gamut Gamma Range Grids 1 2 3
Cinema
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 BT.709
(Gamma 2.2)		 Full,
Narrow		 17,33,65 ✔    
Cinema
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔    
Cinema
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full DCI-P3
Gamut		 DCI
(Gamma 2.6)		 Full 17,33,65 ✔    
Cinema
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.2020
Gamut		 BT.709
(Gamma 2.2)		 Full,
Narrow		 17,33,65 ✔    
Cinema
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.2020
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔    
Cinema
Gamut		 Canon Log 2
Canon Log 3		 Full BT.2020
Gamut		 PQ Full,
Narrow		 17,33,65 ✔    
Cinema
Gamut		 Canon Log 2
Canon Log 3		 Full BT.2020
Gamut		 HLG Full,
Narrow		 17,33,65 ✔    
DCI-P3
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 BT.709
(Gamma 2.2)		 Full,
Narrow		 17,33,65 ✔    
DCI-P3
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔    
DCI-P3
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full DCI-P3
Gamut		 DCI
(Gamma 2.6)		 Full 17,33,65 ✔    
BT.2020
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 BT.709
(Gamma 2.2)		 Full,
Narrow		 17,33,65 ✔   ✔
BT.2020
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔   ✔
BT.2020
Gamut		 Canon Log
Canon Log 2
Canon Log 3		 Full BT.2020
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔   ✔
BT.709
Gamut		 Canon Log Full BT.709
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔ ✔  
BT.709
Gamut		 Canon Log 2
Canon Log 3		 Full BT.709
Gamut		 Wide DR Full,
Narrow		 17,33,65 ✔   ✔
BT.2020
Gamut		 Wide DR Narrow BT.709
Gamut		 Wide DR Narrow 17,33,65 ✔   ✔
 
  • File naming conventions
    [Gamut]_[Gamma]-to-[Gamut]_[Gamma]_[GridNum]_[Range][Range]_[Version].cube
        (1)            (2)               (3)           (4)             (5)            (6)         (7)           (8)
Example: CinemaGamut_CanonLog-to-BT709_BT709_17_FF_Ver.1.1.cube
  1. Input gamut
  2. Input gamma
  3. Output gamut
  4. Output gamma
  5. Grids
  6. Input range (N: Narrow, F: Full)
  7. Output range (N: Narrow, F: Full, L: Linear)
  8. Version
  • Explanation of the data format
    Example: 17 Grid version
     
    Lines beginning with the pound sign (#) Comments about the 3D LUT file
    LUT_3D_SIZE 17 Table size (17 x 17 x 17)
     
    0.000000 0.000000 0.000000   Data (R G B, red fastest)
    0.000026 0.000000 0.000000    
    0.079094 0.000000 0.001118    
    0.205855 0.000250 0.000000    
 
 
  • LUTs for conversions to Wide DR
    The Narrow range version of Wide DR is a curve that was used into the super-whites
    (outputs over 100%), whereas with the Full range version of Wide DR, this curve is
    compressed in a format to fit within 100% output.
     
  • Nominal signal levels of conversion LUT from Canon Log 2/3 to PQ/HLG
    These LUT are used to convert to the perceptual quantization (PQ) and Hybrid Log-Gamma (HLG) defined by Recommendation ITU-R BT.2100-2.
    Conversion is performed to achieve the signal levels described in TABLE 1 of Report ITU-R BT.2408-1.
     
  • HLG-Vivid
    This HLG corresponds to the traditional colour described in section 6.5 of Report ITU-R BT.2390-4.
    This results in expression with higher saturation than that of the BT.2100 compliant HLG.

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