Issues related to being underwater
The first and foremost problem of taking sphere images underwater is finding the correct location to center the sphere. This isn’t much different from selecting the center of a sphere on land other than you can’t see a prospective location from more than a few meters away if you are underwater and need to be able to guess at possible locations from aerial photographs or from the surface. The only real solution to this is to get really familiar with an area by exploration and have the camera rig ready to go in the boat when you find what you are looking for.
Your chances of arriving at an unknown destination, leaping in the water and shooting a spectacular sphere image are pretty slim. Local dive guides can suggest great “dive spots” but these may or may not be suitable for a sphere image. For example, dive operators like “drift dives” and “drop-offs” and almost always require swimming with a group that will vanish before you can get your sphere done. So you need to tell the guide you are looking for a dive spot where there is something visible in all directions and preferably not over 4 meters deep; a place where the sea life is abundant and colorful. Tell the guide you need a location where there is not much wave action or current.
The next problem is accessibility to the location. You need to be in a reasonably protected location. Taking a sphere image is difficult if there are significant waves or currents since you and the camera will be moving all over the place – especially in shallow water. You also need to be at the location on a sunny day. Since the wind direction and strength and cloud cover changes from day to day any one location might – or might not – be accessible when you can be there. So if you plan to take sphere images the best location is one you have been to before and can access easily over at least a week in the hope of having at least one day of nice weather.
You also have to be comfortable with the normal difficulties, dangers and pitfalls of diving or snorkelling so you can concentrate on your photography. You are not going to have much luck with a foggy mask half filled with water or fighting to submerge because you don’t have enough weights or inhaling seawater with every other breath. In short, sphere imaging underwater requires that you are completely at home in the sea. It also requires that you have a diving partner that shares this facility. Another consideration is that your diving buddy has to pay attention and when you start taking a sphere he or she has to either get out of the scene or stay in one place. You will be concentrating on the camera and won’t be able to keep an eye on what your dive partner is up to.