Nikon COOLPIX W300 Reference Manual page 71

C
Focus and Exposure When Shooting with the Self-timer
n10s, n2s: The focus and exposure are locked when you press the shutter-release
button all the way down.
r5s: The focus and exposure are set right before the shutter is released.
C
The Self-timer Setting
The setting may not be available with some shooting modes (A62).
Shooting Features
Self-timer
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