As part of what is believed to be a huge firmware update in April, Canon Rumors is reporting that their sources are confirming that C-Log will be added to the Canon platform and that an announcement will be made at NAB to hype the news.
A popular choice with those shooting on the Cinema EOS platform, as well as various other flavours of Log by ARRI, RED and others, the C-Log gamma curve is able to capture as much data information over the entire dynamic range of a camera sensor. C-Log is able to do this by remapping your image brightness values and exposure levels. For example, 18% middle grey, which is normally 50%IRE, moves down to around 32-33%. 90%IRE (white) will appear on your waveform monitor at only 62-63%. Using new values like this will enable you to maximize the dynamic range your sensor is designed to capture.
The result is an extremely flat looking image with very little contrast. This can make it a challenge for all but a well-trained eye to expose properly, but the result is the ability to pull expose in the darkest of corners and the brightest of images and still pull out a workable image in post when you perform a standard “d-log” of the footage and begin colour grading.
Shooters are well advised to keep grey cards, a light meter, and a working knowledge of their camera’s ISO and lenses so that they can expose for it properly. You can also check out Canon’s white paper on C-Log here.
The bottom line is that if Canon does bring C-Log to the 5D Mk IV platform, it will go a long way towards closing the gap with both Sony’s a7 and the Panasonic GH5 platforms.