I was diving with two advanced photographers. The big rig heavy duty cameras were impressive. I don’t use one. It would break my heart if I got water damage. So I am content to use my Canon G12 and natural light. We were headed back. Suddenly one of the photographers pointed and then twisted and turned into position to shoot. I white balanced and peered into the blue. There were two fish circling. The loss of detail made them hard to identify. Tuna? No jacks. They were jacks. Predatory fish, they were circling but we couldn’t see why. Meanwhile I just shot instinctively. At this distance no amount of flash was going to make to much difference. Photoshop enhancement and it is easy enough to make out. They are jacks because I was told so.