thinned out by means of various methods by carrying out the zoom processing like this by altering a magnification smoothly in terms of time it becomes possible to obtain a moving image which is zoomed in or zoomed out the video signal in the memory 110 which is processed into a video of an appropriate magnification by the digital zoom circuit 111 is then subjected to processings such as a color correction processing and a white balance processing after that the video signal is outputted to a recording medium such as a semiconductor memory an optical disk or a magnetic tape or an external device such as a personal computer or a television monitor the microcomputer 112 reads a zoom command signal outputted from a zoom operation portion 118 which is operated in order to change an amount of zooming magnification here an explanation will be made as to a case where the microcomputer 112 carries out an optical zoom control in a rear focus type optical system as in this embodiment the lens cannot be focused by merely moving a variator lens 103 in order to perform zooming this is because the relationship between a position of the variator lens 103 zoom lens and the position of a focus lens 106 for keeping a focused state varies in a complicated manner depending on an object distance as shown in fig4 accordingly the microcomputer 112 detects the position of the variator lens 103 and the focus lens 106 by means of a zoom lens position detection.