Sony a7 IV Shutter Angle Hack Explained – Service Mode, Hidden LUT Code, De-Squeeze and 5K 3:2 Scan Mode

How ToCamera Hacks

by Nino LeitnerToday

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A community research project has switched the Sony a7 IV to shutter angle by changing one stored setting through Sony’s USB service mode, with no modified firmware involved. The same project documents custom LUT code, a de-squeeze display and a full-height 5K 3:2 sensor mode inside firmware 6.02, and explains why most of them stay out of reach.

This is part three of our series on camera firmware hacks. In the overview article, I described how AI assistants have made it much easier to take camera firmware apart. The Sony a7 IV feature research project on GitHub is a good example of how far that goes, and also of where it stops. Its author opens the documentation with a clear line: “Use this at your own risk, I am not responsible for any damages.” I would add that this is a tool for people who are comfortable with a terminal and who keep a backup of everything before they start.

The project works with the Sony ILCE-7M4 on firmware 6.02. Sony sells the a7 IV as a hybrid camera, and it gives shutter angle, de-squeeze display and Log Shooting with custom LUTs to its Cinema Line bodies such as the FX30 and FX3 instead. That separation is exactly what this research project looks at.

How the method works

The a7 IV has a USB service mode that Sony uses for repairs. The open-source tool Sony-PMCA-RE, maintained by developer ma1co, can switch the camera into that mode and open a shell. If the name sounds familiar: ma1co is the same developer whose work removed the 30-minute recording limit on Sony Alpha cameras in 2016, which we covered at the time.

In the service shell, the camera’s settings are stored as numbered backup properties, and the project documents commands to read, write and save them. Nothing in the firmware is replaced. The procedure the developer recommends is strict: save a complete backup of the settings first, change one property at a time, save, switch the camera off, disconnect USB, remove the battery for ten seconds, and only then test. The original value goes back before the next experiment. According to the project, the backup it created was 2,369,436 bytes and passed Sony’s own checksum, and it should stay private because it can contain camera identifiers.

Shutter angle on the a7 IV

Shutter angle is the one feature that is verified on a physical camera. The property that selects shutter speed or shutter angle exists in the a7 IV backup, and setting it from 00 to 01 made the camera show the shutter-angle icon and 180° in Movie mode after a cold boot. A second property holds the angle itself, and the project lists values from 360° down to 5.6°, including 172.8°, 144° and 86.4°, which can be written directly through the service shell. The FX3-style Shutter Mode menu does not appear, but it only chooses between speed and angle, which the stored setting already does.

There is a catch that the documentation is open about. The main README says that the a7 IV on firmware 6.02 still routes the touch and dial controls away from the angle setter, so adjusting the angle with the camera’s own controls is not fully solved. The step-by-step guide describes a dial setup in Movie mode with Manual Exposure or Shutter Priority, while the status table lists the adjustment as “still gated”. In my opinion, that means you should treat this as a fixed 180° shutter with the option to set other angles over USB, until the developer confirms more. Restoring shutter speed is the same procedure with 00.

Custom LUTs: the code is there, the menu is not

The finding that surprised me most is the LUT code. The a7 IV firmware contains the full software side of Sony’s Log Shooting feature, according to the project: S709, R709 and S-Log3 built-in LUTs, 16 user LUT slots, parsing of 17 and 33-point .cube files, import and edit functions and the display path. The developer set the Log Shooting property to Flexible ISO, the camera accepted it and kept it after a cold boot, and nothing changed. No menu appeared.

The reason is in what the project calls the product class. The a7 IV runs Sony’s shared camera application as a product class called LS, while two other classes in the same code, LAX and ALCIN_UUD, are marked as Cinema Line. The rule that makes Log Shooting available names 14 product classes and leaves out LS. So this is not a missing switch but a product decision written into the firmware tables, and the documentation says so plainly. An earlier version of the notes had identified the a7 IV as LAX, and the developer corrected it publicly, which I find reassuring.

De-squeeze and open gate

The de-squeeze display is the most promising candidate. The a7 IV has no De-Squeeze Display menu, while the FX3 and other Cinema Line bodies offer 1.3x and 2.0x. The project found a stored setting with exactly those values and traced its path to the image and display blocks, with no product check on the way. Because it changes only the display, not the recorded file, it would be a low-risk change. But the project grades it a “strong candidate” and says clearly that nothing has been tested on a camera yet.

Open gate is a different story. The shared application contains a 5016 x 3344 resolution, which is exactly 3:2, and scan-mode names for full-frame 5K 3:2, 16:9 and 17:9. The developer points out that Sony uses the same set of modes on the Sony FX5, where open gate records in X-OCN only. On the a7 IV, the encoder profiles go no further than 4096 x 2160, and no recording path for the 3:2 mode was found. The conclusion in the documentation: “No tested backup-property change enables Open Gate recording.” I am almost 100% certain that this code is simply shared with Sony’s cinema cameras, but that’s just my guess.

Older Sony bodies: PlayMemories apps return

Owners of older Sony cameras have a simpler route. Bodies such as the original a7, a7R, a7S, a7 II, a6000, a6300, a5100, NEX-6 and RX100 III to V supported Sony’s PlayMemories Camera Apps, small official apps that added features like multiple exposure, Light Painting, Star Trail, Digital Filter and Touchless Shutter. Sony closed the store, but Sony-PMCA-RE can still install the apps over USB, and several photographers have now done this with an AI assistant guiding them through the setup. Not every app runs well on every body: apps made for newer cameras can crash on older ones.

What Sony could take from this

Most of what this project found is not a missing feature but a deliberate line between product families. Sony puts shutter angle, de-squeeze and custom LUTs on the FX30 and FX3, and keeps them off the a7 IV. From a business point of view, I understand that. But the a7 IV is one of the most popular hybrid cameras for video work, and these are menu items, not hardware. (Sony, if you are reading this, a shutter-angle option and a de-squeeze display on the a7 IV would cost you one firmware update, and nobody would buy an FX3 less because of it.)

Price and availability

The Sony a7 IV feature research project and Sony-PMCA-RE are free and open source on GitHub. The research repository contains no Sony firmware, keys or camera backups; users have to get the official firmware update themselves. Using service mode is at your own risk and outside Sony’s support. The Sony a7 IV body costs $1,998 at B&H and €1,941.32 at CVP (plus tax). For more information, please visit the Sony website.

Would you use a service-mode change like this on your own a7 IV? Which feature from the FX line would you like Sony to bring to it? Let me know what you think in the comments below!