Triggering sharp images can be tricky. Here are three ways to improve the quality of your images:
1. Push the camera against some other teeth for stabilization
2. Images can also be triggered by touching the screen.
3. Using voice control

Here's how it works

Setup voice control

Go to "voice control" settings,
press "customise commands"

Press "custom"

Press "Create New Command..."

Enter phrase "take image", press "action"

"Select "Run Custom Gesture"

Press in the middle, 
press "Save"

That's it!