As a cinematographer, you’re often bombarded with technical terms like RAW, log, compression, and LUTs. These are essential concepts in digital filmmaking, but they can get confusing.
In this guide, I’ll break them down for you in simple terms so you can understand how each one works and when to use them.
Let’s get started. Watch the video first:
What is RAW?
When we talk about RAW (always in all caps), we’re referring to the unprocessed data that comes directly from the camera’s sensor.
This data hasn’t been processed into an image yet, which means you have a lot of control over how it looks later in post-production.
Cameras with RAW capabilities might not show you a final image right away.
Instead, they collect data from the sensor’s color filter, called a Bayer filter. This filter separates light into red, green, and blue values, but the data itself is just raw light information. To turn this data into a viewable image, it has to go through a process called debayering.
The Importance of RAW
RAW files give you the highest quality image possible because nothing has been altered yet.
You can adjust things like white balance, exposure, and color grading without losing quality. For professionals, this is the best format because it offers the most flexibility.
However, RAW files are usually large, and you might special software like Adobe Premiere Pro or DaVinci Resolve to open and edit them.
Log: The Digital Version of Film
Cinematographers who started working with digital cameras wanted a workflow similar to film workflows. This is where log comes in.
Log is designed to mimic the way film captures images, giving you a “flat” image that holds a lot of detail in highlights and shadows.
When you shoot in log, the footage might look dull and flat on your monitor. This is because log preserves a wider dynamic range (the difference between the darkest and brightest parts of an image), allowing you more flexibility when color grading.
Why Use Log?
The main reason to use log is to preserve as much information as possible for post-production. You don’t want to lose detail in the bright or dark areas of your shot, and log helps you avoid that.
Most high-end cameras allow you to shoot in log, and this format has become the industry standard.
However, because log footage looks flat and unappealing to the naked eye, you’ll need to apply a LUT to preview what the final image will look like.
What are LUTs?
LUT stands for Look-Up Table. A LUT is essentially a preset that adjusts the color and contrast of your footage, transforming that flat log image into something more visually appealing.
Think of it like a filter that gives you an instant idea of how your final image might look.
How LUTs work
LUTs take your log footage and apply a set formula to it.
The formula tells the software how to adjust the brightness, contrast, and color so that the footage looks more like what you’d expect in the final product.
Many cameras come with pre-installed LUTs that you can use while shooting, and you can also create your own or download others.
There are LUTs for various color standards, like Rec. 709 (which is a standard for HDTVs and Internet Video) or DCI-P3 (the standard for theatrical projection).
A LUT can help you get a consistent look across all your footage, whether you’re shooting for TV, film, or online content.
How Compression fits in
Compression is simply the process of reducing the size of your video file. Cameras can record in either uncompressed or compressed formats, depending on your needs and storage capacity.
Read this article to learn more about how compression works:
Why Compress video at all?
Video files, especially RAW files, can get enormous. To save space, cameras compress the data, removing unnecessary information without losing much visible quality.
The level of compression varies. Today, most cinema cameras offer compressed RAW formats that still maintain high quality.
The downside to compression is that too much of it can lead to a loss of detail. You might notice artifacts, color banding, or other unwanted effects if the video is over-compressed.
Now let’s make sense of it all.
RAW, Log, LUTs, and Compression: A Cinematographer’s Guide
Let’s break down how these elements work together:
- Shooting in RAW: When you shoot in RAW, you’re capturing all the unprocessed data from the camera’s sensor. This gives you maximum control over the image but requires more storage space and processing power. However, you still need a way to see the image.
- Debayering and Log: After shooting in RAW, the camera or software will debayer the footage, converting the raw data into an image. Log is one way to present this image. Shooting in log helps preserve the dynamic range and detail in your image, giving you flexibility in post-production. Remember this: When you’re shooting in RAW, you’re most likely also recording the image in Log. They are not mutually exclusive. Even if the camera will show you an image in Rec. 709 or HDR, while it is recording RAW, the image is still being written in Log.
- Using LUTs: On set, you might apply a LUT to see how the flat log footage will look after grading. This helps you make quick adjustments to lighting or exposure during the shoot.
- Compression: Depending on your camera and storage, you might be able to choose a compression setting for your footage. Some cameras allow you to shoot in compressed RAW, which balances file size and quality.
Workflow Example: The Arri Alexa
The Arri Alexa is a great example of how all these tools come together.
When you shoot on an Alexa, you have the option to record in ARRIRAW, which gives you uncompressed data. This data is then converted to LogC, Arri’s log format, preserving the dynamic range of the footage.
When recording RAW, the footage written on cards is always ARRIRAW+LogC.
To preview the final image on set, cinematographers use an official Arri LUT, which converts the log footage to Rec. 709 or DCI-P3, depending on the project’s final delivery format.
This workflow is the gold standard for all cinema cameras because of its simplicity and effectiveness.
As a cinematographer, your goal is to capture the best image possible, whether you’re shooting RAW or compressed video, log or standard footage. The key is to understand how each tool works and when to use it.
If you want the most control over your image, shoot in RAW. If you want flexibility in post-production, log is the way to go. Use LUTs on set to preview your footage and ensure your look is consistent. And finally, don’t forget about compression when managing your file sizes.
At the end of the day, great cinematography is about knowing your tools and making them work for your vision. So, go out there and shoot something amazing!
Bravo, perfect explanations
Thank you!
Good, fast and with nice examples – as always. Thanks!
You’re welcome!
Nice video, thank you for taking the time to explain this crucial workflow. As a longtime content creator, semi pro cinematographer, this is very important for me to know as I keep shooting RAW, and color grade my own projects.
You’re welcome!
fantastic, something new to learn.