If our current Mobile Movie of the Week “Submerged” makes you want to shoot underwater, here’s a BBC Earth Unplugged tutorial to help you get started.

While the 6-minute video offers a variety of clever, low-cost tips, the most interesting one is to use a small fish tank. This will enable you to get split screen shots—the bottom half of the frame underwater, the top half above.

The tutorial’s location is an aquarium, but we’ve seen the same approach used in a swimming pool.

The video does begin with a warning not to allow smartphones to get wet. That is good advice even if your phone—like the iPhone 11— is rated as “water resistant.”