S-Log, HLG and why you should be using them for your movies

[_J.G.M_]

Camera technology has evolved so much that the sensors in modern cameras are now capable of matching, or even surpassing, 35mm film quality. The problem is that existing video formats don’t support the vast amount of information captured by a modern camera, resulting in reduced dynamic range and colour.

S-Log and HLG are two solutions.

What is S-Log?

S-Log is a gamma curve designed to record and transmit as much of the information recorded by your camera’s sensor as possible. It has been specially optimised for digital motion picture cameras, so whilst cinematographers shooting in the current REC.709 standard must choose to sacrifice detail in either the highlights or shadows, S-Log allows you to retain all the information, giving you greater control over the final images in post-production.

When you use S-Log, the benefits are noticeable straightaway. You get:

• A wider range of tones - S-Log is especially effective when shooting in strong sunlight or dark shadows, preventing the loss of detail in overblown highlights and shadowy areas.
• Greater colour gamut - The wider the colour gamut, the more colour information can be recorded, making your images more vibrant and realistic.
• More control - With more information to play with during the edit, you have increased control over the final product.

When shooting in S-Log, post-production colour grading is essential in order to display the footage on a standard REC.709 monitor, but rather than an extra step, this should be recognised as an advantage because you’ll have far greater jurisdiction over the finished materials than you would if they were shot natively in REC.709.

Sony Look Profiles are designed to simplify the colour grading process. Supplied as 3D LUT (Lookup Table) files, they convert S-Log footage to REC.709, making it easy, even for beginners. Advanced users can use the Look Profiles as a base to build upon and further refine. 

What is HLG?

Hybrid Log-Gamma, or HLG, provides an instantaneous HDR (High Dynamic Range) workflow. That means movies recorded in HLG picture mode, which you’ll find on cameras such as the α7R III, will appear true-to-life without colour grading. And as HLG content is display-independent, it will work on SDR (Standard Dynamic Range) and HDR sets.

Shooting in HLG is particularly useful for projects requiring a fast turnaround. For instance, if you were covering a live event and wanted to get the footage online straightaway, you could reduce or completely eliminate the time you’d usually need for editing.

As more and more broadcasters favour HDR content, from the BBC to YouTube, it makes sense to produce videos in the highest quality possible. Think of S-Log and HLG as a way of enhancing the production value of your work and future-proofing it! Let us know your experiences of using them below.