A Reddit user, CoupleMother1623, reports that Variable Shutter (flicker-frequency control) and the BIG6 menu item now work on a Sony A7S III. Sony Alpha Rumors covered the post on 3 November 2026. The work builds on a public GitHub research repository, leogenot/sony-a7iv-feature-research, which was written for the A7 IV on firmware 6.02. Menu items for both features exist in the firmware, but Sony hides them on some models through per-model visibility records and greyed-out flags.
The poster says the camera exposes a hidden update channel, called Jiritsu, over USB even in normal Mass Storage mode. A computer writes files into a temporary folder through it, including a library that the camera's own updater loads and runs with root rights inside the main application. From there the author patches the menu gating in RAM, so the items appear and the native settings screen opens. The post gives no A7S III firmware version. Variable Shutter and BIG6 are the only features reported.
Installation therefore needs a computer and a USB cable, not a card or an in-camera app. According to the poster, no firmware is modified and the RAM patches disappear on reboot. The camera's persistent Backup settings memory can also be written directly, and the poster says that one write makes the Variable Shutter setup permanent.
Risks: the claim comes from one user, and a follow-up article found no independent test as of 4 November. Related A7 IV shutter-angle experiments in October were reported to have left a camera unresponsive, although the researcher later said he recovered it. Writing to the settings memory can affect warranty. Back up the settings first and expect no support from Sony. Whether the method works on other Alpha bodies is untested.