If you’re just starting out shooting films or videos, you may have heard of log profiles.
We all know that shooting stills in raw enables far more post-processing latitude than JPEGs. However, the situation is a bit different from video, which is where log comes in.
What is a log?
Log is short for “logarithmic,” referring to the mathematical curve in use.
Recording using a log profile preserves more of the image’s dynamic range and tonal values by redistributing exposure across the entire image.
It provides full control and flexibility on the image quality and the final results.
Why shoot on Log Profile?…And why not?
|Shooting Log||Shooting Normal|
|Detailed Shadows and tonal range||Shadows blackened out|
|Flexible – Easy for post-production to recover contrast, saturation, and using LUTs.||Limited – Can’t change colour profiles get desired while post-production|
|Improved image quality with great tonal and dynamic range||Compromised Image quality|
Mostly cameras record exposure in a linear fashion within the picture itself. But exposure can never be linear! Each exposure stop either doubles or halves the amount of light, meaning that exposure doesn’t change by the same singular amount on a scale.
So the exposure line for an 8-bit video will look like something like this.
As we know, the brightest whites with the value of 256 and blacks on 0. Problem lies is when the system overloads values at the top of the line meaning that all 256 exposure values won’t be evenly spread
You can easily see that the low and mid-range values are pushed up into the upper part expanding our dynamic and tonal range. However, it also completely washes out the image.
This curve is applied before the video is compressed and recorded.
What to do if your camera doesn’t have log ?
Technically, one can tune it up manually to produce a flat image since the log feature is just a colour profile. The idea is to completely desaturate image, lower the contrast and lower the sharpening as well, lower your highlights and shadows by the same amount. Try to get it as flat as possible so that it can be recovered in post.
- In order to get the right final exposure, footage has to be over exposed. So make sure to use all the tools like histogram and zebra lines to get good exposure. If the right exposure the image is not set it can be very grainy and unusable. (varies in different light situations)
- Also, requires a tremendous amount of tweaking time and post-production to get the desired colour and final grade for the footage to be presentable.
Panasonic – Vlog
Sony – Slog
Canon – Clog
Experiment with camera to works and what doesn’t. But all in all, log setting is a great feature and one that is more than welcome to staple all filmmakers and videographers. So Learn, and keep Practicing!