One-inch Type Sensor
A sensor measuring about 13.2 by 8.8 millimetres, with a crop factor near 2.7×, common in premium compacts and drones.
Formula / rule
Crop factor ≈ 2.7
Measured in
mm
In depth
The name is a legacy of vidicon tube sizing and has nothing to do with any actual dimension of the sensor, which measures about 16 mm diagonally. It became the standard for serious compacts because it is roughly four times the area of a phone sensor while still allowing a pocketable body and a usefully fast zoom.
Examples in practice
A drone with a one-inch sensor delivers clean aerial files at ISO 400 where a smaller module would already be noisy.