1. A method of controlling an operation of an electronically controlled camera, a system of the camera including a first memory for storing a program to control the camera, a second memory for storing parameter data representing an operational status of the camera, and a rewritable memory for storing at least one auxiliary process, flag data used for determining whether the at least one auxiliary process is to be executed and operational data including information related to a bit manipulation of the parameter data stored in the second memory, the method comprising the steps of: reading the flag data; determining whether the at least one auxiliary process is to be executed based on the flag data; and executing the at least one auxiliary process when it is determined, in said determining step, that the at least one auxiliary process is to be executed, wherein the at least one auxiliary process comprises the steps of: reading the operational data stored in the rewritable memory; and performing bit manipulation of the parameter data in accordance with the operational data.