Camera
Rolling Shutter
A distortion effect in electronic shutter mode where fast-moving subjects appear skewed or leaning because the sensor reads pixel data line by line rather than all at once, capturing different parts of the frame at slightly different moments.
Rolling shutter is a distortion that occurs when a camera sensor reads pixel data sequentially — row by row from top to bottom — rather than capturing all pixels simultaneously. In a mechanical shutter, a physical curtain sweeps across the sensor at a fixed speed, but the exposure of the film or sensor is considered instantaneous. In electronic shutter mode, the sensor itself must scan through its rows to read the data, and this scan takes time. If anything is moving during that scan — the subject, the camera, or both — the top of the frame and the bottom of the frame reflect different moments in time.
The visual result depends on the type of movement. A car moving horizontally across the frame may appear to lean forward or backward rather than being vertical. A helicopter rotor may appear bent rather than straight. Panning the camera quickly while shooting a static scene can cause vertical lines to lean in the direction of pan. The severity depends on how fast the sensor reads out: a slow readout on a low-end sensor produces strong distortion; a fast readout on a stacked sensor produces almost none.
Rolling shutter is only relevant in electronic shutter mode. When using a mechanical shutter, the physical curtain limits rolling shutter to the curtain travel speed, which is fixed by the hardware and generally less problematic for still subjects. For video, all electronic capture is subject to rolling shutter, which is why sensor readout speed matters significantly in video-oriented cameras like the GH7 and Blackmagic Pocket Cinema Camera 4K. Stacked sensors with fast readout are the primary engineering solution to rolling shutter in modern cameras.