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C-LOG to Rec.709 Exposure Correction LUTs for CANON R5/R6

Note: This post was updated on July 9, 2021 to incorporate information about EOS R6 firmware v1.4.0.

Every videographer and filmmaker strives for perfectly exposed footage in camera. In reality, footage often turns out a little over or underexposed. Some videographers purposely overexpose C-Log for better looking skin tones and highlight detail retention.

Adjusting exposure is a simple fix when editing one or two videos, but slow and potentially inconsistent when editing anything more.

The 60 custom LUTs in this pack convert Canon C-Log and C-Log 3 footage to the Rec.709 color space and adjust exposure using the proper C-Log gamma curve. The LUTs are designed for use with Log footage captured using the Canon EOS R5 or R6, and function similarly to exposure compensation on a camera.

Footage overexposed by 1 stop? Use the -1 Stop Rec.709 LUT. Footage underexposed by 2/3 a stop? Use the +.66 Rec.709 LUT.

These LUTs not only save considerable time and effort when importing and prepping C-Log footage, but they correctly adjust brightness and contrast to match Canon’s native C-Log to Rec.709 LUTs. Under and overexposed footage (within 2 stops) are instantly corrected, and appear as if you nailed their exposure in-camera.

Let’s take a look at before and after examples to see the C-Log to Rec.709 Exposure Correction Luts in action.

Example footage

Below are keyframes from three videos shot using C-Log 3 / Cinema Gamut on an EOS R5. The left is underexposed by 2/3 a stop, the middle is exposed correctly, and the right is overexposed by 2/3 a stop.

Underexposed 2/3 (Left), Correct Exposure (Middle), Overexposed 2/3 (Right)

Now let’s convert these C-Log 3 videos to Rec.709 using Canon’s C-Log 3 Cinema Gamut LUT.

Same Canon C-Log 3 Rec.709 LUT applied to all three videos

They look okay, but as you can see, the left video is darker while the right is brighter. You’d now need to spend time manually editing the exposure of the left and right videos to match. This not only slows down editing, but there’s a chance your brightness and contrast edits may not correctly adjust their blacks, whites, and midtones.

Imagine having to edit an entire project full of footage without this way!

Let’s remove Canon’s LUT from these three videos and use the C-Log to Rec.709 Exposure Correction Pack LUTs instead. The left video below is now using the +0.66_Stops Rec.709 LUT, the middle is using the Native LUT, and the right is using the -0.66_Stops Rec.709 LUT.

Exposure Correction LUTs applied / +0.66 (Left), Native (Middle), -0.66 (Right)

As you can see, the videos now appear nearly identical! No additional color grading or adjustments have been made. All three videos have been converted to Rec.709 and their underlying exposure issues have been resolved.

What’s included in the pack

The C-Log to Rec.709 Exposure Correction Pack includes 60 customized LUTs, plus Canon’s official Rec.709 LUTs for convenience. Each LUT uses Canon’s own C-Log to Rec.709 LUT as a baseline, with additional adjustments to account for under or overexposed brightness and contrast values.

The pack includes the following:

  • 1D / Canon C-Log to Rec.709 (13 Luts)
  • 1D / Canon C-Log 3 to Rec.709 (13 Luts)
  • 3D / Canon C-Log to Rec.709 (13 Luts)
  • 3D / Canon C-Log 3 Cinema Gamut to Rec.709 (13 Luts)
  • 3D / Canon C-Log 3 BT.709 to Rec.709 (13 Luts)
  • User Guide PDF

1D LUTs affect brightness, contrast and black/white values. 3D LUTs affect the same, but also interpolate color. If you’re not sure which to pick, I recommend using the 3D LUTs. They will most likely transform footage the way you are expecting.

LUTs inside each pack are organized like so:

[Lut]_-2.00_Stops.cube
[Lut]_-1.67_Stops.cube
[Lut]_-1.33_Stops.cube
[Lut]_-1.00_Stops.cube
[Lut]_-0.67_Stops.cube
[Lut]_-0.33_Stops.cube
[Lut]_Native.cube
[Lut]_+0.33_Stops.cube
[Lut]_+0.67_Stops.cube
[Lut]_+1.00_Stops.cube
[Lut]_+1.33_Stops.cube
[Lut]_+1.67_Stops.cube
[Lut]_+2.00_Stops.cube

Similar to exposure compensation on a camera, If footage is overexposed, apply a negative LUT. If footage is underexposed, apply a positive LUT. The LUT in the middle has no exposure correction and provides a good starting point.

These LUTs can’t fix clipped blacks or whites (nothing can, really), but as long as your C-Log footage is within 0-109% IRE, it should convert fine.

Compatibility

These LUTs are compatible with the Canon EOS R (C-Log only), EOS R5 and EOS R6. If you don’t see C-Log 3 as a menu option on your EOS R5 or R6, your camera firmware is out of date. Download firmware from Canon through the following links:

Canon EOS R5 Firmware
Canon EOS R6 Firmware

Purchase

The C-Log to Rec.709 Exposure Correction LUTs are affordably priced at $15, and may be purchased by clicking the button below.

Video

Here’s a video where I introduce and demonstrate these LUTs.

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