Press the MENU button on the back of the camera to display the Camera Set-up Menu.
Select "Preview Style" from the Set-Up Menu.
Press the OK button to open the sub menu and select "No CF card".
If "ON" is selected, it will be possible to release the shutter even if there is no CF card in the camera. Selecting "OFF" will disable the shutter release if there is no CF card in the camera.
*Once the firmware update is complete, the "No CF-Card" option will default to "OFF".