I have 3 camera setups that I’m using now, and I use them (or not) at different times. Like most things in life, it’s all a tradeoff between simplifying the dive, flexibility in photography, and image quality.
Action Cam: “Small and Wide”
I have a Paralenz and my wife has a later-model GoPro. They just clip onto your BCD and you don’t need to worry about it unless you find something to shoot. They’re good for wide-angle point-and-click shots and the GoPro with a Backscatter Flip magnifier means that you can take pretty decent macro video and OK macro stills if you add some torch light.
When to take:
Non-intense dive classes with minimal practice skills. Like Advanced Open Water or a deep diver specialty.
Group dives. You don’t have much time to take photos anyway. And the pictures you usually take are of other divers.
New gear where you feel OK with buoyancy and trim but still want more practice dives.
Protip: most divers have pictures of everybody else. Try diving with other photographers and make a “photo sharing pact”.
Olympus TG5: “The Recon”
I had been borrowing my wife’s TG4 with Olympus housing (OK, it was originally mine but then I traded her for her EM-10II because it has a fully manual mode). Now I have a TG5 with a Nauticam housing and light ring. Both of the TGs are pretty cool cameras and if you have the experience and skills you can take some really good pictures. In fact, a good photographer with a compact camera can blow away lesser photographers with a $25000 camera setup.
When to take:
Learning a new area or looking for new critters. The name of the game is covering more distance underwater to learn the layout. You’ll swim more than take photos, and you’ll swim faster if you’re not pushing a large camera through the water.
Lobstering, trash removal, or other activities where photography is secondary but you know that there are good photography subjects in the area.
Dives with heavy current or surge.
Areas where you’ll be taking both wide-angle and macro on the same dive.
Trips where you have a long flight and don’t want to carry a heavy suitcase full of camera gear.
Solo dives where you want to minimize weight getting in to and out of the water. For example, in cold water I have a drysuit, 30+kg of weight, 14L HP cylinder, and a 5.5L stage cylinder. That’s heavy for a shore entry.
Protip: take a SMB, tie it down where you find a good subject, and come back on the next dive with the big camera.
Dives where the main purpose is macro photography.
Tiny subjects perfect for supermacro where you need the magnification that 15x worth of wet diopters will give you.
Times when you need bigger resolution for cropping or printing.
Dark and deep conditions where you need all the flexibility in lighting that you can get: dual strobes, focus light, video light, etc.
Dives where you have a spotter and you can get as much “trigger time” in as possible.
Easier diving conditions. Low current and surge. Shorter swims. Shore or boat crew to assist with entry and exit.
Don’t Take a Camera: “Enjoy the Dive”
There are even some times when I don’t take a camera. *gasp* *cue shock and awe*
When to not take:
Serious dive classes. You can’t do drills and carry another diver out of the water if your hands are full of camera.
Your first 30 dives. Learn buoyancy first, OK? That way you’re not killing coral or animals on the bottom.
Major adjustments in gear or environment. For example, going from tropics to drysuit in cold water. Times where your buoyancy and trim are going to be messed up and you need to focus on that for a handful of dives and the less extra gear you have the better. It reduces your task-loading and stress. Later on, I’ll switch to the TG5 if I’m more comfortable and once I know that I can dive in that setup without problem, I’ll start carrying the G9.