LOG recorded images are very similar to Raw recordings in the sense that they both are created to protect as much of the dynamic range as possible. What makes LOG different from Raw and a regular video file? In this movie, author Patrick Inhofer explains what LOG recorded images are and how they are used.
- Log recorded images are very similar to Raw recordings in that their end goal is the same, to preserve as much dynamic range as possible and giving the colors as much flexibility in post-production as possible. But Raw images never burn in exposure and color balance settings. We can change settings like ISO using Raw controls in our software. Log, not so much. At the time of recording an image, the camera takes the Raw signal, processes it with the current white balance and ISO settings and saves the resulting image into a specific codec with a specific Log curve.
In other words, our digital negative is instantly developed right inside the camera and our job is to take what we're given as our starting point. Log images are video. We can try to fix problems with color balance or exposure but we can't get back to that sensor data and manipulate those settings like we can in Raw. On the other hand, since it's simply video, Log images are much easier to use and much easy on our computers.
The history of Log recorded images is actually very interesting. It started in the film world when Kodak tried to capture the wide dynamic range of film negative into a computer. They developed the Cineon scanning system that took a much wider dynamic range on film and put it into a much smaller container but they kept all the really important image details. It did this by converting the image using a Logarithmic scale that mimics human perception.
It records less detail where human perception is poor and allocates more bits which means more detail in areas where we are extremely perceptive. In other words, Log recordings throw data away but they do it selectively, smartly, based on how we actually see. In fact, it's such a smart solution, this method of recording digital video has taken the industry by storm.
All the major players have their own flavors of Log recordings. Some have multiple flavors optimized for their centric technoLogy and the codecs they use to store the final video. As I quickly bounce between these three different slides, notice that they're all shots of the same exact grayscale, yet they record the image differently because they're using slightly different math to do that recording. Also notice on this waveform how the true black square in the middle, it's lifted well above pure black and the pure white bar on the right is well below that 100% level.
This is a defining feature of Log recordings. Your DP will try to preserve significant blacks and significant highlights resulting in a very flat-looking image. Here's a shot from a series by business partner, Robbie Carman, worked on, notice that it's flat, it's lifeless, not only does it look dull, it actually feels a bit soft. With a few tweaks of a few knobs, here's his final image. It's popping, has color, sharpness, depth.
All of these was already in this image but it was stored in a way that our eyes can't make sense of. Part of the job of a colorist is to take Log footage and make it look it should for human eyes. Let's recap. Log and Raw have the same goal, preserve maximum dynamic range to let us do the final printing of the image later in post-production. And one nice by-product is they both give the DP a little more room for error and they both give the colorist a nice starting point.
The advantage of Log is the computer doesn't have to process the image since it's already video. This will give you more real-time playback even when you're adding additional effects on it and frequently, the media files are smaller and they're usually much easier to share. The problem is, since it's normal video, mistakes in the original capture will leave forever. We can correct many of the problems but if extreme enough, sometimes you just going to throw a shot away.
The flat look can confuse and annoy our clients and there's no way to judge sharpness looking at a flat image. Finally, Log footage can be very confusing to color correct but then, that's why we're here today and we'll solve that problem very, very shortly.
Once you're familiar with the differences between log, raw, and flat recordings, explore two different methods for color correcting that footage. First, Patrick shows you how to color correct manually, using the traditional tools in DaVinci Resolve. Then, he explains how to use lookup tables (LUT), and discusses LUT strengths and limitations.
- Differentiating between raw and log recordings
- Differentiating between cameras that record flat vs. log
- Setting project-wide raw and LUT preferences
- Applying LUTs to footage
- Exporting LUTs from Resolve
- Color correcting raw footage
- Color correcting log footage
- Using LUTs with log, raw, and flat footage
- Importing, exporting, and managing LUTs in Resolve