Reddit
reddit.com › r/cinematography › what are s-log, c-log, etc?
r/cinematography on Reddit: What are S-log, C-log, etc?
October 16, 2013 -
Probably an amateur question, but reading American Cinematographer, I occasionally come across mention of "gamma function," S-log, C-log, and other logs. I was wondering what exactly these are, and what purpose they serve and so on? Thanks!
Top answer 1 of 3
26
S-log is referring to an uncorrected sensor output that is flat and low in contrast. This image is taken into a color corrector where the colorist has more control over what colors he chooses to accentuate and the detail in the blacks and highlights is preserved. On most video cameras a Gamma Curve called REC709 is applied which brings the image levels close to what we see with our eyes, this is great for the average user, but for those who want more control, it is better to bypass the default in camera processing. C-log just refers to Canon's "log" shooting mode.
2 of 3
3
Log is a format that compresses data very efficiently into the storage available. Every stop of dynamic range gets the same perceptual storage space, as opposed to linear gamma which is how the sensor sees the world and is very inefficient. (Someone here linked to my article that explains why.) The reason log looks flat is because you're often cramming 10-14 stops into the Rec 709 HD spec, which was only meant for about six stops initially. That means every two stops is crammed into a space meant for one, which lowers contrast considerably. Log refers to a logarithmically-encoded gamma curve. Gamma controls contrast and is separate from color space, which is something completely different although most log curves are meant to work within a specific color space (such as Sony's S-Log2 and S-Gamut). Log is not meant to be viewed directly: it is a storage medium only. You need to apply a LUT or some sort of gamma correction so that it looks proper on a Rec 709 display. (Rec 709 is the standard for HD broadcast that enables an image shot on a Rec 709-complaint camera to look normal on a monitor.) Viewing it directly results in a flat, colorless image. Log is NOT uncorrected sensor output. You'll never actually see that. Even viewing "raw" in cameras like REDs isn't raw, because raw is just Bayer pattern information that isn't viewable at all by humans on any device without some kind of processing. (If a camera manufacturer says they are showing you "raw" they are not being entirely truthful. They are showing you some representation of raw that has been processed to be viewable on a Rec 709 display but you are not seeing true raw.) Log is a way of processing raw data in such a way that the same information can be encoded in fewer bits. The rule of thumb I've heard is that you can capture the dynamic range of 12-bit raw in 10-bit log. Log is definitely not a replacement for raw as there are things you can do with raw that you can't do with log, such as go back to the same footage years later with a different deBayering algorithm and pull even more information out of it. It's the next best thing, though, and most TV series shoot log because it's a very efficient way to capture a lot of information for grading. (Features tend to capture raw more often than log.) Every manufacturer has their own flavor of log that works slightly differently. In particular, they each put middle gray and 100% white at different points on the gamma curve. It's important to know this as it helps with determining exposure and judging how much dynamic range you are getting above middle gray. Edit: wrote raw instead of log in last paragraph. Ooops.
Canon Europe
canon-europe.com › professional photography & video › stories
Enhance your filmmaking with Canon Log - Canon Europe
Canon Log was first introduced in 2011 for the Canon EOS C300 and through the years different versions of Canon Log have been added to an ever-increasing number of Canon cameras including (but not limited to) the EOS C400, EOS R5 Mark II, EOS R50 V, PowerShot V1 and EOS R5 C (pictured).
Videos
How To Expose And Colour Grade For Canon C LOG 2 ...
04:55
Canon C-Log Color Grading – Fast, Simple LUT Workflow - YouTube
05:19
C-Log 3 on Canon: What It Is, How to Use It, and Why It Matters ...
11:32
Mastering C-LOG 3: The Ultimate Guide to Cinematic Exposure - YouTube
34:05
C-Log Color Grading - Easy Techniques (Including FREE) - Premiere ...
Canon C-LOG Vs C-LOG3 Comparison | What’s The Difference? - YouTube
What is the difference between Canon Log, Canon Log 2 and Canon Log 3?
The original Canon Log delivers a dynamic range of approximately 12 stops, Canon Log 2 up to 16 stops, and Canon Log 3 up to 14 stops. Canon Log 2 retains more detail in darker areas than Canon Log 3 but also features an elevated noise floor. Canon Log 3 is easier to grade thanks to producing a cleaner image and retains the same amount of highlight information as Canon Log 2.
canon-europe.com
canon-europe.com › professional photography & video › stories
Enhance your filmmaking with Canon Log - Canon Europe
What is Canon Log used for?
Canon Log is used to capture video footage that has a wider dynamic range and exposure latitude than standard video. The Canon Log tone curve is applied at the point of capture to retain more details in the highlights and shadows compared to standard video.
canon-europe.com
canon-europe.com › professional photography & video › stories
Enhance your filmmaking with Canon Log - Canon Europe
How does Canon Log help with colour grading in post-production?
Canon Log helps with colour grading as it is recorded at 10-bit colour depth and provides a flat image with low saturation that is an excellent foundation for colour adjustments and HDR workflows. It is easier to match footage shot on different cameras that have been set to Canon Log, enabling clips from Cinema EOS and EOS mirrorless cameras to be combined and colour matched to give a consistent look on a multi-cam shoot.
canon-europe.com
canon-europe.com › professional photography & video › stories
Enhance your filmmaking with Canon Log - Canon Europe
Foliovision
foliovision.com › 2020 › 01 › how-to-grade-canon-c-log
How to Grade Canon C-Log: Three Step Workflow - Foliovision
January 15, 2020 - When Carey asked for some tips on how to improve the grade on Canon C-Log, Henry Eckstein stepped up and delivered a three part class on how to grade Canon C-Log step by step, including adjusting exposure, white balance and sharpness.
Canon Community
community.usa.canon.com › t5 › EOS-DSLR-Mirrorless-Cameras › EOS-R-Why-use-C-Log3 › td-p › 474476
EOS R: Why use C Log3? - Canon Community
December 15, 2024 - Using C-Log3 or any Log profile for that matter is most important if you want to get the most out of the cameras sensor to get the most DR (Dynamic Range) which basically means the most highlights and shadows of the image can be retained at the same time in the image.
Fstoppers
fstoppers.com › video-editing › explaining-most-things-about-canon-log-c-log-get-started-filmmaking-684752
Explaining Most of the Things About Canon Log (C-Log) to Get You Started in Filmmaking | Fstoppers
November 23, 2024 - Each camera has its own native ISO value that yields the best dynamic range, and some cameras even have dual native ISO, with one optimized for low-light scenes and another one optimized for bright scenes. For the Canon 5D Mark IV, Canon recommends using ISO 400 when shooting in C-Log to achieve the best dynamic range.
ARRI
arri.com › en › learn-help › learn-help-camera-system › image-science › log-c
Log C | Image Science | Learn & Help
Images encoded with Log C (C is for Cineon; the original Cineon log encoding is based on the density of color film negative) can be identified by their flat and desaturated nature.
EOSHD
eoshd.com › news › eoshd-c-log-and-film-simulation-picture-profiles-for-canon
EOSHD C-LOG and Film Simulation Picture Profiles for Canon - EOSHD.com - Filmmaking Gear and Camera Reviews
May 6, 2024 - EOSHD C-LOG is designed to expand dynamic range and give Canon DSLRs without official “Canon LOG” the same capabilities. With C-LOG you gain a professional LOG colour grading workflow, and more dynamic range in post.
CINECOLOR
cinecolor.io › products › canon-c-log
CANON C-LOG – CINECOLOR
CANON C-LOG is backordered and will ship as soon as it is back in stock.
EOSHD
eoshd.com › store › eoshd-c-log1
EOSHD C-LOG and Film Profiles for Canon DSLR and mirrorless cameras - EOSHD.com - Filmmaking Gear and Camera Reviews
November 29, 2023 - The EOSHD C-LOG and Film Profiles pack installs a “Canon LOG” picture style on cameras previously without it, plus a range of film simulation modes.
GitHub
github.com › rxi › log.c
GitHub - rxi/log.c: A simple logging library implemented in C99 · GitHub
A simple logging library implemented in C99. Contribute to rxi/log.c development by creating an account on GitHub.
Starred by 3.4K users
Forked by 683 users
Languages C
Programiz
programiz.com › c-programming › library-function › math.h › log
C log() - C Standard Library
The log() function computes the natural logarithm of an argument.
W3Schools
w3schools.com › c › ref_math_log.php
C Math log() Function
The natural logarithm is the logarithm with base e. The value of e is approximately 2.718282. Some implementations of the <math.h> library include a constant M_E but it is not guaranteed to be available.
Hingsberg
hingsberg.com › 2013 › 01 › canon-c-log-exposed-literally
Canon C-LOG exposed, literally
Whether it’s S-LOG, C-LOG, LOG-C or any other flavour of the LOG gamma curve they all have one common goal and that is to preserve as much data information over the entire dynamic range of the camera sensor as possible.
Wikipedia
en.wikipedia.org › wiki › Log_profile
Log profile - Wikipedia
January 7, 2026 - In early times of digital cinematography, professional video cameras were only capable to capture linear sensor image up to 10-bit color depth even in HDCAM-SR format, but resulted in "video-look" compared with film stock cinematography even in the same 24 frames per second and shutter speeds. The log gamma profile began gaining industrial popularity since 2005, when Arri released Arriflex D-20 which provided original Log-C gamma through HD-SDI video output, and further in 2008, when Sony released CineAlta F35 camera (and its 2005 Panavision Genesis sibling) with S-Log video recording on HDCAM-SR tape.
GeeksforGeeks
geeksforgeeks.org › c language › c-log-function
C log() Function - GeeksforGeeks
June 26, 2024 - log() function in C programming is a mathematical function provided by the math.h header file and is used to calculate the natural logarithm (base(e)) of a given number passed as parameter.
Calculator.net
calculator.net › home › math › log calculator
Log Calculator
When the argument of a logarithm is the product of two numerals, the logarithm can be re-written as the addition of the logarithm of each of the numerals.
Top answer 1 of 6
24
You can use this
File logger.h
#ifndef LOGGER_H
#define LOGGER_H
void logger(const char* tag, const char* message);
#endif /* LOG_H */
File logger.c
#include "logger.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void logger(const char* tag, const char* message) {
time_t now;
time(&now);
printf("%s [%s]: %s\n", ctime(&now), tag, message);
}
It's probably not perfect, but it does satisfy the needs as you have presented them.
2 of 6
11
I suggest the log library which is written by myself --- zlog!
The way to fit your need in zlog is:
$ vi /etc/zlog.conf
[formats]
simple = "%D %c %m%n"
# don't know what the tag mean in your question, so put category of zlog instead
# log level is also available here, add %V means level
[rules]
my_cat.* "xxx.log"; simple
$ vi hello.c
#include <stdio.h>
#include "zlog.h"
int main(int argc, char** argv)
{
int rc;
zlog_category_t *c;
rc = dzlog_init("/etc/zlog.conf", "my_cat");
if (rc) {
printf("init failed\n");
return -1;
}
zlog_info(c, "hello, zlog");
zlog_fini();
return 0;
}
It will generate xxx.log in current directory as
2012-09-30 07:22:50 my_cat hello, zlog
Links:
Download: https://github.com/HardySimpson/zlog/archive/latest-stable.tar.gz
UsersGuide: http://hardysimpson.github.com/zlog/UsersGuide-EN.html
Hompage: http://hardysimpson.github.com/zlog/
Canon Asia
snapshot.canon-asia.com › article › eng › videography-faq-what-is-canon-log
Videography FAQ: What is Canon Log?
September 15, 2023 - It is known as "log" as it encodes along a logarithmic scale instead of a linear one. The resulting footage contains more information on tone variations that are visible to us, which is also why they appear to have less contrast straight out of the camera.
Conan.io
conan.io › center › recipes › log.c
log.c - Conan 2.0: C and C++ Open Source Package Manager
github.com/rxi/log.c · 2023-02-11 · ab41f3f0917832b9de0... Linux · Windows · macOS · macOS Apple Silicon · Windows ARM64 · Add the following line to your conanfile.txt: [requires] log.c/cci.20200620 ·
Reddit
reddit.com › r/programming › github - rxi/log.c: a simple logging library implemented in c99
r/programming on Reddit: GitHub - rxi/log.c: A simple logging library implemented in C99
February 13, 2022 - Announcing iceoryx2 v0.7: Fast and Robust Inter-Process Communication (IPC) Library for Rust, Python, C++, and C ... Take a Look at My Old Thread-Safe Logging Library "clog"!