I use my 20mm wide angle lens about 80% of the time. Not only for those wide reef scenes but mostly for wide angle close-up fish portraits. My 20mm does a fine job for whale sharks, wrecks and reefs. Besides, I'm not aware of lenses available in those other lengths available for your camera. Those choices are more common to SLR's.
As for taking it on and off, it depends on the dive sight. If I'm shooting macros along a wall where the possibility of something really big to come from behind or below, it's nice to know I can quickly add the WA to get the shot. Just because I have the ability to switch between lenses it doesn't mean I have to, but the ability to be able to do so has been priceless.
As for taking it on and off, it depends on the dive sight. If I'm shooting macros along a wall where the possibility of something really big to come from behind or below, it's nice to know I can quickly add the WA to get the shot. Just because I have the ability to switch between lenses it doesn't mean I have to, but the ability to be able to do so has been priceless.