Sony A7S IV rumors: what the WW261362 registration does and doesn't tell filmmakers

This is a rumor. Sony hasn't announced an A7S IV, and nobody outside Sony knows what the camera registered in China as WW261362 is. SonyAlphaRumors reported the filing on 28 September 2026 (Wi-Fi 6, applicant Sony Japan) and bets on an A7S IV in November. PetaPixel thinks an FX3 II makes more sense. As of 14 November there's no teaser and no date, and a second code has surfaced in California (see the update below).

The A7S III shipped in 2020 and it's still the low-light Alpha most video shooters ask about, so plenty of people are sitting on a purchase. We traced each claim to where it came from, put the rumored specs next to what Sony already sells in the A7S III, FX3 and FX5, and worked out who should hold off.

What's in the Sony registration?

A radio filing tells you a device has Wi-Fi or Bluetooth and who applied for it, and little else.

The Wi-Fi 6 line is the only hardware detail with a document behind it. Sony's spec sheets for the A7S III and the FX3 list IEEE 802.11ac, which is Wi-Fi 5, so WW261362 isn't a relabelled version of either.

Update, 14 November: a second code shows up in California

On 10 November SonyAlphaRumors pointed to an entry in the California Energy Commission's appliance database, added on 31 October. It lists an unreleased Sony camera under the code WW491229. The site says the code doesn't belong to any existing model, and that the battery in the listing is the NP-SA100, which it says only the FX5 and the A7R VI use today. We couldn't open the database ourselves, so everything below comes from SonyAlphaRumors' reading of it.

What changes for you: the battery points away from a small FX3-class body and toward the FX5 and A7R VI tier, which makes an FX3 II look less likely. It doesn't tell you whether the camera is an A7S IV. SonyAlphaRumors also rules out the new $80,000 medium format cine camera, because that one doesn't take this battery. If you were waiting for a cheap low-light body, nothing here says it'll be cheap.

Which A7S IV rumors hold up?

Our grading: strong means a document backs it, likely means it fits one, weak means one site with nobody named.

Nothing new has surfaced in the five weeks since. SonyAlphaRumors' posts from 5 to 7 November cover Tamron, sales figures and an A7S III that runs DOOM, with no word on a launch.

How would it stack up against the A7S III, FX3 and FX5?

The first three columns are Sony's published specs. The last one is the rumor, so read it as a guess.

We didn't find current official euro or sterling prices for the A7S III and FX3 on Sony's European stores for this piece, and street prices move every week before Christmas. Check two or three dealers before you decide.

What would a 16MP stacked sensor change on set?

If the rumor is right, you'd notice two changes on day one.

Readout speed comes first. A stacked sensor reads out faster, so pans, handheld work and the gimbal wobble you get walking with the camera skew less. That's the A7S III's weak spot next to the FX5, and it's the upgrade we'd pay for first.

The second is framing room. Run the numbers on a 3:2 sensor and 16MP comes to roughly 4,900 by 3,270 pixels. The A7S III's sensor is 4,240 wide, which is only about 10% wider than 4K UHD. At 16MP you'd have around 28% extra width over UHD for oversampling or a punch-in, and 16.6MP works out to about 4,990 pixels wide, which matches the FX5's 5K mode. That fits the idea of a shared sensor, though it doesn't prove it.

The open question is low light, the reason anyone buys an S. A third more pixels on the same area means smaller photosites. Stacked designs and newer processing can make up some of that, but only side-by-side tests will tell you whether the new body keeps the A7S III's clean high ISO. Until someone posts sample files, any low-light claim is a guess.

Should you wait or buy now?

If you're on an A7S III and miss shutter angle, read our piece on the A7S III shutter angle hack before you spend money. If the FX5 is on your list, our FX5 shipping date guide explains the delays, and the Sony timecode guide covers which bodies take a timecode input.

What to check if Sony announces it

• The megapixel count and whether Sony calls the sensor stacked. That settles the FX5 link.
• Rolling shutter figures from the first lab tests, then high ISO samples against the A7S III.
• Internal RAW, open gate and shutter angle. The FX5 has all three at least in part, the A7S III has none.
• Cooling. A fan or a heat-sink design decides whether it can replace an FX3 on long takes.
• Euro and sterling prices and the European ship date, which slipped by months on the FX5.

A7S IV questions people ask

Sources

• SonyAlphaRumors, the WW261362 registration (28 September 2026), and its follow-up on PetaPixel's view (7 October)
• SonyAlphaRumors, "Sony registered a new camera code in California!" (10 November 2026), the WW491229 entry. We could not open the California database ourselves
• PetaPixel, "Is a Sony a7S IV Coming? Fat Chance" (29 September)
• Imaging Resource (30 September), with the rumored spec list; Digital Camera World and DIYPhotography
• Sony specifications: A7S III product page and A7S III Help Guide; FX5 figures from Sony's press text and our FX5 article; FX3 launch price from Wikipedia
• Sensor widths: 4FILMMAKERS calculation for a 3:2 sensor, from the megapixel figures above
• Cover: Sony A7S III (the current model, not the new camera), photo by Henry Söderlund, CC BY 2.0 via Wikimedia Commons, cropped and graded by 4FILMMAKERS