A digital camera could be considered as a device which digitally samples a 2D signal. For correct sampling of consecutive frames in time, camera capture rate should be 2 times the display refresh rate ( ) unless there is a synchronization system in place to activate the camera shutter when the image is stabilized on the display (exactly between frame changes). As it is not normally the case, if the camera capture rate is for example Hz then the display refresh rate could not exceed 4 Hz.