in smaller sizes have been around for a while, but Sony is the first to develop a full frame sensor with the facility and the A9 III is the first mass-production digital mirrorless camera to be equipped with one. Sensor shutters typically make an exposure – and an image – progressively by scanning the scene line-by-line vertically which, while it can be done a lot faster than with a physical shutter, still has some limitations… chiefly
