imaging signals from the imaging unit 310 the external interface 325 includes various encoders a d a converter and the like transmitting and receiving various control signals or data with respect to external elements in the embodiment a display 360 a memory medium 340 and an operation panel unit 350 connected to the system control unit 320 the display 360 is a small display such as a liquid crystal panel incorporated in the camera apparatus displaying the imaged pictures in addition to the small display incorporated in the camera apparatus it is possible to apply a configuration in which image data is transmitted to an external large display device to display the data the memory medium 340 is capable of appropriately storing taken pictures for example in various kinds of memory cards and the like which can be exchanged for example with respect to a memory medium controller 341 as the memory medium 340 in addition to various memory cards disc media and the like using magnetic or light can be used the operation panel 350 is provided with input keys for performing various instructions by the user when taking pictures by the camera apparatus the cpu 321 monitors input signals from the operation panel unit 350 and executes various operation controls based on the inputted contents the embodiments of the invention are applied to the above camera apparatus thereby providing an imaging apparatus having high quality which performs proper power supply at the time of activation of the apparatus or at the time of sudden load change and which realizes speed up of activation operation and suppressing load change in the above configuration the combination of unit devices or unit modules to be components of the system or the size.