Step 1: Open camera app in your device
Step 2: Tap Settings gear icon at upper right corner
Here you can see Huawei P20 Pro camera settings such as enable Master AI, GPS tag, capture smiles, 4D predictive focus and other settings.
Step 3: Scroll down up to end of the page and tap ultra snapshot
Step 4: Choose take a quick snapshot
Step 5: Now press volume down button two times when screen is off to quickly capture snapshot in your Huawei P20 Pro
Camera > Settings > Ultra snapshot > Take a quick snapshot / Open camera / Off
Automatically take photos when your face detected as smiles in your device.
4D Predictive focus
Show the point of focus on moving objects in real time.