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Sony a7S III

Real Sensor Data

Brand
Sony
Sensor Format
Full Frame
Resolution
12.1 MP
Pixel Pitch
8.45 microns
Circle of Confusion
0.0288 mm
Crop Factor
1.00x
Announced
2020

Every other full-frame body on this site's reference has climbed toward higher resolution over successive generations; the a7S III, released in 2020, deliberately went the opposite direction, holding its sensor at just 12.1 megapixels — a genuinely low figure by current standards, chosen specifically because larger individual photosites gather more light per pixel, which is exactly what a camera built primarily for video and extreme low-light stills needs.

Sony a7S III sensor specs

Sensor
Full Frame
Resolution
12.1 MP
Pixel dimensions
4,260 × 2,840 px
Aspect ratio
3:2
Pixel pitch
8.45 µm
Crop factor
1.00x
Circle of confusion
0.0288 mm

Full Frame sensor · DoF & Hyperfocal Calculator · Astro 500/NPF Calculator

Sony also gave the a7S III a fully articulating screen, a first for the a7S line, alongside a completely redesigned menu system that later became the template for every Sony full-frame body since.

See these numbers used live in the DoF & Hyperfocal Calculator by selecting the Full Frame sensor format.

Frequently Asked Questions

Why would anyone choose a 12-megapixel camera in the current market?

For video and extreme low-light stills specifically, where larger individual pixels gathering more light per pixel matters more than resolution — the a7S III is a deliberately specialized tool, not a general-purpose high-resolution body, and photographers who need large prints or heavy cropping should look elsewhere in Sony's lineup.

Is the a7S III good for astrophotography?

Yes, genuinely — its unusually large pixel pitch gives it one of the longest maximum shutter speeds before star trailing becomes visible under the NPF rule of any full-frame camera on this site, a direct benefit of the same low-resolution sensor that helps its video and low-light performance.