The Base ISO Shift: F-Log vs F-Log2
Unlike traditional video profiles where base ISO is 160 or 200, logarithmic curves require the camera sensor to distribute its analog gain differently to safeguard highlight rolloff:
Original F-Log: Native base ISO is ISO 640. It provides 12 stops of dynamic range, with 18% middle grey placed at 38 IRE. It is forgiving and clean straight out of camera, but clips early in specular clouds.
F-Log2: Native base ISO jumps to ISO 1250 (on the X-H2S stacked sensor) or ISO 1000. It expands dynamic range to 14+ stops, but remaps 18% middle grey down to a low 32 IRE. Because the baseline image appears darker on your monitor, beginners panic and push ISO to 3200, immediately introducing macro-blocking noise.
Always expose F-Log2 by +1.0 to +1.3 EV over nominal using your camera's exposure compensation dial or histogram. At +1.0 EV, middle grey sits around 42 IRE and caucasian skin tones rest safely between 50–58 IRE. In post-production, pull your offset or primary exposure down. The shadows become velvety clean, with zero chromatic noise.
Fujifilm Waveform Exposure Targets
Use the following IRE values when monitoring your shot via internal camera zebras or external Ninja V/Blackmagic monitors:
| Zone | F-Log (Nominal) | F-Log2 (Nominal) | Optimal Production Target (ETTR) |
|---|---|---|---|
| 18% Middle Grey | 38 IRE | 32 IRE | 42 – 44 IRE |
| Average Skin Tones | 50 – 55 IRE | 45 – 50 IRE | 52 – 58 IRE |
| 90% White Card | 73 IRE | 68 IRE | 75 – 78 IRE |
| Highlight Clip Boundary | 100 IRE | 100 IRE | Keep specular under 94 IRE |
How to Cure the Infamous "Fuji Green Cast"
Many editors notice that after applying the official Fujifilm Rec.709 or Eterna LUT, skin tones appear slightly jaundiced or greenish-olive under mixed lighting. This is rooted in the non-Bayer color filter array of X-Trans sensors, which gives preference to green spectral transmission for resolution.
In your camera's White Balance shift grid, set R: +1 to +2, B: -1 to -2. This balances warmth towards healthy pinkish-orange blood flow.
In DaVinci Resolve or Premiere Lumetri, nudge the Tint slider (+4 to +8) towards Magenta on your pre-LUT node to align with the vectorscope skin-tone line.
Explore 50+ Fujifilm Color Recipes & LUTs
Direct in-camera JPEG recipes and calibrated 3D .CUBE transforms for F-Log and F-Log2 based on real film stocks.