Entocentric lens with a focal length smaller than the sensor diagonal, eg an f = 6mm lens on a 1/2″ sensor (the sensor size has 8mm).
When we use the word “wide angle lens”, it must be clear what sensor is used.
The same lens can, depending on the sensor, be wide-angle, telephoto lens and normal lens.
A lens of f = 8mm on a 1/3 “sensor (6mm diagonal) a slight telephoto lens.
On a 1/2 “Sensor (8mm diagonal) it is a normal lens and on a 2/3” sensor (with 11mm diagonal) a wide-angle lens.
On a 1/2 “Sensor (8mm diagonal) it is a normal lens and on a 2/3” sensor (with 11mm diagonal) a wide-angle lens.
see discussion under normal lens