Hi @m_ocean !
You’re going to need to adjust the focus manually - this is a bit tricky, and may take a lot of guess / check - in air the focus will be blurry, but in water it will be clear… Creating a small mark on the rotating and stationary point before you begin can be a great reference!
For the Blue Robotics low-light camera, if things are a bit blurry underwater the lens is rotated about 1/2 to 3/4 of a turn counter clockwise to correct. You’re shooting to get the focus on objects very very close to the dome - see this calculator.