Sony DSC-RX100M4 Instruction Manual page 188

[137] How to Use
Long Exposure NR (still image)
When you set the shutter speed to 1/3 second(s) or longer (long exposure shooting), noise
reduction is turned on for the duration that the shutter is open. With the function turned on,
the grainy noise typical of long exposures is reduced.
1. MENU →
Menu item details
On:
Activates noise reduction for the same duration that the shutter is open. When noise
reduction is in progress, a message appears and you cannot take another picture. Select this
to prioritize the image quality.
Off:
Does not activate noise reduction. Select this to prioritize the timing of shooting.
Note
Noise reduction may not be activated even if [
following situations:
The shooting mode is set to [Sweep Panorama].
[Drive Mode] is set to [Cont. Shooting], [Spd Priority Cont.] or [Cont. Bracket].
The shooting mode is set to [Scene Selection] and [Sports Action], [Hand-held Twilight] or [Anti
Motion Blur] is selected.
The ISO sensitivity is set to [Multi Frame NR].
You cannot set [
[Intelligent Auto], [Superior Auto] or [Scene Selection].
Depending on the shooting conditions, the camera may not perform noise reduction, even
if the shutter speed is longer than 1/3 second(s).
[138] How to Use
High ISO NR (still image)
When shooting with high ISO sensitivity, the product reduces noise that becomes more
noticeable when the product sensitivity is high. A message may be displayed during noise
reduction processing; you cannot shoot another image until the message disappears.
Using shooting functions
(Camera Settings) → [
Long Exposure NR] to [Off] when the shooting mode is set to
Using shooting functions
Setting the other functions of this product
Long Exposure NR] → desired setting.
Long Exposure NR] is set to [On] in the
Setting the other functions of this product