The image pickup apparatus includes a lens barrel, and two barrier blade groups each configured to include a first barrier blade, a second barrier blade and a third barrier blade, each barrier blade group being movable between a closing position for covering a front face of the lens barrel and an opening position for opening the front face of the lens barrel. Alternatively, information for detecting the specified ground pattern is stored in a storage device, in order to detect the ground pattern with the stored information. The temporary storage accommodations may be units having a generally circular lading envelope, and an hexagonal optimal packing density. The input circuit is coupled to the second input of the second transistor.