Log recording is a video camera recording mode in which sensor data is encoded with a logarithmic transfer curve instead of a display-ready gamma, so that the widest possible dynamic range fits into the limited code values of a video file. In video cameras, log modes such as S-Log3, V-Log, C-Log3, LogC and Blackmagic Film are the standard way to capture a flat, grade-ready image without the data size of RAW video.
A log image looks low in contrast and saturation on a normal monitor because it is not meant to be viewed directly. It must be transformed to a display standard such as Rec. 709 or an HDR format, using a LUT or a color-managed pipeline, before it looks correct.
How log recording encodes light
Camera sensors respond linearly to light: doubling the light doubles the signal. In a linear encoding, half of all code values describe the brightest stop, while the darkest stops receive very few. A logarithmic curve instead assigns a roughly equal number of code values to each stop, which matches how exposure is measured and how the eye perceives brightness.
The practical result is that a 10-bit log file can hold 12 to 15 or more stops of scene dynamic range with usable precision, depending on the sensor. A standard Rec. 709 gamma would clip highlights and crush shadows to fit the scene into a display range of about 6 to 7 stops.
| Encoding | Distribution of code values | Typical use |
|---|---|---|
| Linear | Half the values in the brightest stop | RAW sensor data, VFX compositing |
| Display gamma (Rec. 709) | Optimized for a viewing display | Finished video, live broadcast |
| Log | Similar number of values per stop | Acquisition for grading |
| Hybrid curves (HLG) | Gamma in shadows, log in highlights | Live HDR broadcast |
Common log formats and their characteristics
Each manufacturer defines its own log curve and matching color gamut, so log footage from different cameras is not interchangeable without the correct transform. The table summarizes widely used formats; exact values depend on camera model and firmware.
| Log format | Manufacturer | Paired gamut | Notes |
|---|---|---|---|
| S-Log3 | Sony | S-Gamut3 or S-Gamut3.Cine | Middle gray placed near 41 percent signal level |
| V-Log | Panasonic | V-Gamut | Designed to match VariCam color science |
| C-Log2 and C-Log3 | Canon | Cinema Gamut | C-Log3 trades some range for easier grading |
| LogC3 and LogC4 | ARRI | ARRI Wide Gamut 3 or 4 | LogC4 accompanies newer sensors with extended range |
| Blackmagic Film | Blackmagic Design | Blackmagic Wide Gamut | Generation-specific curves |
| N-Log and F-Log2 | Nikon and Fujifilm | Rec. 2020-based gamuts | Common in hybrid mirrorless cameras |
Log curves differ mainly in where they place middle gray and white, and in how much headroom they reserve for highlights. Grading software and ACES workflows provide manufacturer-specific input transforms that convert each curve into a common working space.
Log recording compared with RAW video and standard profiles
Log recording sits between a finished standard profile and RAW video. It preserves far more grading latitude than Rec. 709, but unlike RAW the image has already been debayered, white balanced and compressed in camera.
| Capture option | Grading latitude | File size | Fixed in camera |
|---|---|---|---|
| Standard profile (Rec. 709) | Low | Small | Gamma, white balance, sharpening, look |
| Log recording | High | Moderate | White balance, debayering, compression |
| RAW video | Highest | Large | Very little beyond sensor settings |
| HLG | Moderate | Small to moderate | Display-ready HDR look |
Log footage benefits strongly from 10-bit or higher recording. In 8-bit codecs, the flat image spreads too few code values across each stop, and grading can reveal banding in skies and skin tones. Many crews use an external recorder to capture log in ProRes or similar 10-bit formats.
Exposing correctly in log
Exposure in log follows different rules than in a display profile. Because the monitor shows a flat image, operators rely on waveforms, false color and exposure indexes rather than on how the picture looks. Many log modes also impose a minimum ISO, often the camera’s base or higher native ISO.
Most modern sensors reward slight overexposure in log, often by one stop or less, because it lifts the shadows away from noise. The amount depends on the sensor and the scene, and pushing too far risks clipping highlights that cannot be recovered.
| Tool | What it shows | How it helps |
|---|---|---|
| Monitoring LUT | A display-ready preview of the log image | Judging contrast and composition |
| Waveform monitor | Signal level across the frame | Placing middle gray and highlights precisely |
| False color | Color-coded exposure zones | Fast check of skin tones and clipping |
| Zebras | Stripes above a chosen level | Warning of highlight clipping |
Limitations and common mistakes
Log recording is not automatically better than a standard profile. It moves work from the camera into post-production and adds risk when the workflow is not prepared for it.
- Underexposing log produces noisy shadows that become worse when contrast is restored in grading.
- Using the wrong LUT or transform for the camera’s log curve and gamut causes incorrect contrast and color shifts.
- Recording log in 8-bit on consumer codecs invites banding and blocky gradients.
- Choosing log for quick turnaround work such as news can waste time when no grading is planned.
- Relying on a flat monitor image without a viewing LUT leads to poor focus and exposure decisions.
Used correctly, log recording delivers maximum flexibility at a manageable data rate, which is why it remains the default acquisition mode on most cinema cameras and on many hybrid cameras used for professional work.
In simple terms
Log recording is a way of filming that keeps as much detail as possible in both the bright and dark parts of a scene. The video looks gray and washed out straight from the camera, which surprises many people the first time they see it.
Think of it as packing a suitcase very efficiently so nothing is left behind. The contents look crumpled at first, but after unpacking during color grading, everything is there to be arranged into the final look.
A practical example
A small crew films an interview inside a dim workshop, with a bright window behind the subject. In a standard profile, the window would turn pure white while the face stayed correctly exposed. The camera operator switches to log recording in 10-bit 4:2:2 and monitors through a Rec. 709 viewing LUT.
Using false color, she places the face slightly above normal exposure and confirms that the window stays just below clipping. In grading, the colorist applies the matching camera transform, brings back the trees and sky outside the window, and lifts the shadows without visible noise. The finished interview shows a natural face and a detailed exterior in the same shot, without additional lighting or window filters.