Sony DSC-RX100M4 Instruction Manual page 194

When the Electronic Viewfinder is pushed down, the images are always displayed on the
screen regardless of the [FINDER/MONITOR] setting.
[146] How to Use
Release w/o Card
Sets whether the shutter can be released when no memory card has been inserted.
(Custom Settings) → [Release w/o Card] → desired setting.
1. MENU→
Menu item details
Enable:
Releases the shutter even if no memory card has been inserted.
Disable:
Does not release the shutter when no memory card has been inserted.
Note
When no memory card has been inserted, the images shot will not be saved.
The default setting is [Enable]. It is recommended that you select [Disable] prior to actual
shooting.
[147] How to Use
Shutter Type (still image)
You can set whether to shoot with a mechanical shutter or an electronic shutter.
1. MENU→
(Custom Settings)→[
Menu item details
Auto:
The shutter type is automatically switched based on the shooting conditions and shutter
speed.
Mechanical Shut.:
Shoot with the mechanical shutter only.
Using shooting functions
Using shooting functions
Setting the other functions of this product
Setting the other functions of this product
Shutter Type]→desired setting.