Stacked and global-shutter sensors
2017 (Sony α9); 2023 (Sony α9 III global shutter)
Placing memory and processing layers directly under the pixels lets the sensor read out very fast, nearly ending the distortions of electronic shutters.
How it began
CMOS sensors read out row by row. With an electronic shutter this takes long enough to skew moving subjects. From 2012 Sony made stacked sensors for phones, and in 2017 put one in a full-frame camera, the α9.
How it works
The pixel layer is bonded on top of separate chips for circuitry and memory, connected through millions of tiny links. Data can be read out and buffered very fast. A global-shutter sensor goes further, capturing every pixel at the same instant.
Why it mattered
Cameras could shoot silently at 20 to 120 frames a second without a mechanical shutter, and phones could merge many frames quickly for computational photography.
Limits and what replaced it
Stacked sensors are expensive, and global shutters have so far had less dynamic range. Both are improving fast.
Today
Top cameras and most phones use stacked sensors; global shutters are spreading.