We were diving Bonaire the last two weeks. While there, I asked John Wall of the Buddy Dive Photo Center if he had any recommendations for settings for underwater video. I use 4K/30p video exclusively.
He surprised me by suggesting 1/125 shutter speed instead of the 1/60 I had been using.
The purpose, he said, was to reduce motion blur for moving subjects.
I wondered if that would reduce the light enough to cause problems, but the result with my AX100/Gates setup has been truly better in my amateur eyes. And not just a little bit - a lot!
Underwater video came out much better. I went back to using auto WB, auto GAIN/ISO and auto IRIS (F-stop), locking shutter speed at 1/125 and got some of the best video so far with that setup.
I tried it topside on flamingos and other subjects and was also well pleased.
I said to John well, if some's good more must be better, right? He said no, that if you increase the shutter speed beyond 1/125 you begin to get a "cathedral effect" where vertical light streaks appear in the video. I did observe this in shallow water at 1/125 when the top part of the scene was brightly lit, but the bottom area was darker.
There were a few circumstances where the visibility was poor that were not very good. Not sure how 1/60 would have done there as it was contrast that suffered. The camera still seemed to autofocus OK.
1/125 has now become my standard setting - I'm sure I will deviate back to 1/60 if circumstances require it.
This was news to me - I'd been using 1/60 for a couple of years.
Any comments or other advice?