1. An image pickup apparatus comprising: a plurality of imaging devices; a plurality of solid lenses configured to respectively form an image on the plurality of the imaging devices; a plurality of non-solid lenses configured to respectively form the image on the plurality of the imaging devices, and to respectively be changed a refractive index distribution thereof; a video composition processing unit configured to generate a video signal by composing image signals output by the plurality of the imaging devices; and a control unit configured to control an optical axis of a light entering at least one of the plurality of the imaging devices by changing the refractive index distribution of at least one of the plurality of the non-solid lenses such that an energy of first frequency for the video signal becomes greater than a predetermined threshold value, wherein the first frequency is higher than a second frequency, and the second frequency is maximum frequency imageable by the at least one of the plurality of the imaging devices.