Monday, May 29, 2023

The film look and Lumix S cameras

This is the third of four tutorials on optimising DaVinci Resolve for Panasonic Lumix footage. In the first article I conducted a practical test of Lumix S5 footage and stabilisation. The second article walked through an ACES workflow for DaVinci Resolve. This post will provide specific camera settings for you to use. The final article develops a Film Look PowerGrade that you can use in your Resolve projects.

We begin by asking what makes the film look in the first place.

What is the film look?

Back in analogue days, film-makers struggled to get clarity and dynamics into their footage, with deep depth of field being a signature of an exceptional cinematographer. Now that digital perfection is at our fingertips, it's common for film-makers to introduce errors, glitches, and other artifacts of optical film.  Thin depth of field is the rage. Irony aside, there is something appealing about a more organic aesthetic, since digital video can be too sharp, harsh, and revealing.

There are several characteristics of film that we can mimic in digital recordings.

First, the aspect ratio. The original film ratio of horizontal to vertical lengths was 4:3. But when television standardised on the same ratio, feature movies increasingly promoted a widescreen look. This began in 1953 with a trio of films from different studios, the most famous of which is Paramount's Shane (dir. George Stevens). Today it's become trendy to use anamorphic lenses even on domestic cameras. 

Second, the frame rate. While sports footage can benefit from rates at 60 frames per second, the film standard of 24 fps remains ideal for narrative and other work. By setting the shutter angle at 180 degrees, the blur between each frame has an appealing look similar to optical film.

Third, the exposure curve. The luminance of a digital video signal is normally mapped linearly from pure black to pure white, which is not at all how optical film works. One of the appealing characteristics of film is the soft roll-off of highlights, avoiding those horrid burnt-out white areas. Similarly the curve in the shadows has a "toe" that preserves detail. (Though film doesn't treat the darker regions as well as digital can.)

We get a film look by adopting a logarithmic curve that preserves more usable exposure information. This is especially important if we are trying to cram all that exposure information into only 10 bits per colour channel. In camera, log footage is low contrast and desaturated. But it offers much latitude in post-processing. (You can read Panasonic's own explanation.)

Setting up your Lumix camera

Using the Lumix S5, we can easily meet these criteria.

To set up your camera, ensure the PASM dial is set to the "video M" setting. Enter the menu and choose the first icon (video camera). In the second column, also choose the first icon (Image Quality 1). You will want to change "Exposure Mode" to "M" so we can control our exposure parameters explicitly. 

Now, change the second setting, "Photo Style" to "V-Log" in order to get Panasonic's version of the log exposure curve. This is also called Varicam log or some variation. It also changes the colour space to V-Gamut, though this is not explicitly acknowledged.

The third setting on this page is "SS/Gain Operation". Change this to "ANGLE/ISO" so that the shutter readout will be in angles and not fractions of a second. 

Now move to the third icon in the second column, "Image Format 1". Three settings need changing, but these are not provided in a logical order. First go to "Rec. File Format" and choose MOV, as this container gives you more options. Second, choose "Switch NTSC/PAL" and choose "NTSC". This determines the available frame rates.

Finally you can choose "Rec Quality" and set this to the highest possible quality at 24fps. This should be the fourth selection, labelled "C4K | 24p | 422/10-L". C4K is what Panasonic calls DCI 4K, a frame 4096 by 2160 pixels. This gives us a widescreen 17:9 ratio. The frame rate is actually 23.98 fps due to drop frame shenanigans.

This setting gives us 10-bit colour (4:2:2) using LongGOP compression. This is easy for software to handle, since the data rate is "only" 150 Mbps. At least on my computer there's no need for proxies in Resolve. But if you are using a laptop, you might have a different experience!

Here's a summary of the menu settings:

  • VIDEO > Image Quality 1 > Exposure Mode = M
  • VIDEO > Image Quality 1 > Photo Style = V-Log
  • VIDEO > Image Quality 1 > SS/Gain Operation = ANGLE/ISO
  • VIDEO > Image Format 1> Rec. File Format = MOV
  • VIDEO > Image Format 1> Switch NTSC/PAL = NTSC
  • VIDEO > Image Format 1> Rec Quality = [C4K | 24p | 422/10-L]

Besides these settings, I ensure that the front dial will control aperture. Though not explicitly stated in the menus, this assigns shutter angle to the back dial. Unfortunately there is no way to prevent this. I don't want shutter angle on any dial, since I would never wish to change it during a shoot. Mixing different visual flows is only needed if slow motion or some other special effect is required, in which case the entire recording mode and frame rate is changing anyway.

I consider this a significant deficiency of the Lumix S interface. I shouldn't be forced to have shutter angle on a dial! It's too easy to mistakenly touch and move this control. 

While it is possible to assign a button to lock the dials, this locks both front and back. There is no way to simply lock the rear dial.

OK, our camera is set up. We can now shoot footage similar to that in my demo videos. In the next article I will explain how to further the film look through colour grading. 


No comments:

Post a Comment