iPhone 7 or higher may experience camera shake because of the camera lens. Using the included ND filter can help with this.
How to use an ND filter with ROV
Once connected to the ROV Motion app focus on your subject
Select "M" from the option menu on the right hand side of the screen
If your shutter speed defaults to more than 1/60th, you'll want to use an ND filter
To use your ND filter:
Hit the "ND" button on the left hand side of the screen. This will have on-screen instructions.
Attach ND filter over your phone's lens
Twist the variable ND filter until the the bar in the middle of the screen turns green, this indicates the proper exposure for most conditions. This will result in a cinematic effect when filming, alleviating shake and vibration by locking the shutter speed and ISO and controlling the incoming light instead.