1. An imaging device for capturing an image of a scene, comprising: an image sensor; an optical arrangement operable to focus light from a portion of the scene onto the image sensor whilst preventing light from other portions of the scene from being focused onto the sensor; a controller configured to cause the optical arrangement to focus light from a sequence of portions of the scene onto the sensor so that the sensor captures the said sequence of portions of the scene; and a processor configured to use the captured portions of the scene to construct an image of the scene.