Sony a7S III export settings
for a client review link.

Two things in that table decide your workflow. First, 4K 120p exists only in the Long GOP formats, XAVC HS and XAVC S; the Intra format tops out at 60p. Second, XAVC S is the one family with 8-bit 4:2:0 modes, and XAVC HS is the one without a 30p or 25p row in 4K: for a 29.97 timeline in 4K, the choice is XAVC S or XAVC S-I.

The camera’s log options are S-Log2 and S-Log3, with S-Gamut, S-Gamut3.Cine and S-Gamut3 colour modes; Sony’s Picture Profile presets pair S-Log3 with S-Gamut3.Cine (PP8) or S-Gamut3 (PP9). On system software Version 4.00 or later, the help guide also documents a Log shooting page with Log Shooting Setting and LUT options. Whatever you monitor with on set, the recorded file is log, and the log is what leaves the card.

Why the chroma matters is covered in 4:2:0 vs 4:2:2 chroma subsampling. The short version: 4:2:2 keeps twice the colour samples of 4:2:0, which shows up in keys, skin and hard colour edges once the grade pushes saturation.

Even where a device does decode the camera’s 10-bit 4:2:2 profile, an ungraded S-Log3 clip will look flat and washed out, because a browser shows the file as encoded and applies no LUT. The details of which devices decode what are in HEVC 10-bit 4:2:2 in the browser. For an a7S III shoot, the practical answer is simple: grade, then export.

The macOS app is built for a different job. Supported camera originals and Vault playback use the compatible macOS app; they are not universally playable in web browsers. XAVC is not among those originals, so do not plan an a7S III review around the app playing the card files.

Within a range, let the picture pick the number. Calm interview frames hold up at 40 to 50 Mbps. With a movie ISO range of 80 to 102,400 (extendable to 409,600), the a7S III is often shot in low light, and high-ISO grain, night rain, snow, water, foliage and fast pans are the busy frames that want 100 to 120 Mbps. A log grade that lifts shadows lifts their noise too, so err high on dark material.

For 120p, the Long GOP clip is almost always a slow-motion source: conform it to the 23.98 or 29.97 timeline and export at that rate with a constant frame rate. A 119.88 fps review file is not what the client is approving. Free export presets that carry these values for DaVinci Resolve, Premiere Pro, Media Encoder and Compressor are on the NLE page. Other Sony bodies share this logic with different recording tables: see the FX3 and FX30 pages.

The size gap is the reason for the export. A minute of XAVC S-I 4K at 600 Mbps is about 4.5 GB; the same minute as an 80 Mbps HEVC review file is about 0.6 GB (both computed: Mbps divided by 8, times 60 seconds). Replacing the file with a new cut keeps the link, notes and approvals, and colour or smoothness can still differ from device to device.