1. An imaging apparatus for performing predetermined image signal processing on an image signal picked up by an image pickup device in order to convert the image signal for recording and display purposes, said imaging apparatus comprising: a parameter storage section configured to store output correction parameters used to output the picked-up image signal to the outside, and simulation correction parameters used in simulation mode subsequent to imaging; a parameter setting section configured to select said simulation correction parameters if said simulation mode is set based on an externally designated input, and to select said output correction parameters if said simulation mode is canceled, the selected parameters being retrieved from said parameter storage section, said parameter setting section further changing the parameters for gamma correction between said simulation mode and non-simulation mode; a gamma correction processing section configured to perform gamma correction processing on the input image signal based on either said output correction parameters or said simulation correction parameters set by said parameter setting section; and a display-ready signal conversion section configured to convert into a display-ready signal said image signal having undergone the gamma correction based on said simulation correction parameters when said simulation mode is set.