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 correct an image signal's dynamic range and output the picked-up image signal to the outside, and simulation correction parameters used in a simulation mode to correct image toning of a simulated post-production processed version of said image signal, wherein post-production processing comprises editing picked up image signals; a parameter setting section configured to select said simulation correction parameters if said simulation mode is set, 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 a non-simulation mode; a gamma correction processing section configured to perform gamma correction processing on an image signal input thereto based on either said output correction parameters or said simulation correction parameters selected by said parameter setting section; 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, thereby providing a simulated gamma-corrected post-production processed image signal ready for post-production processing; and a metadata storage section configured to store as metadata the simulation correction parameters used for gamma correction processing on the image signal input thereto for subsequent use of said metadata in post-production processing of the image signal picked up by said image pickup device.