Guys, you are missing what I'd consider a more important point. Without bantering
the concepts of burning coral or damaging fish eyes, consider these points.
1. To go on a night dive one typically wants to see nocturnal critters. "Most" night
hunters will run away from bright lights. You will most likely see less of the
nighttime critters with a brighter light. (The opposite side of this coin is the
hunter that takes advantage of your light and hunts with you.)
2. If your eyes get used to seeing "bright" light, then your peripheral night vision
will be diminished. Sure, you'll see what is in the beam of your light, but you'll
miss a lot of movement in the fringes. Again, you'll most likely see less nighttime
critters.
... and finally, fish often use a lot of resources to create a sleeping environment
that will make them (reasonably) invisible to the nocturnal hunters. If using a
bright light disturbs these fish, or attracts a hunter to them, then you will have
shortened the life of a sleeping fish.
I'm not as experienced in night diving as a lot of members on this forum but I do one
every chance that I can. And, we all have our preferences/experiences.
Pesonnally, I've never felt the need for more than a Mini C light in a blue water
night dive.
So, don't condemn the DM for suggesting a lower intensity lamp. His suggestion
to use smaller light is based on experience and knowledge of the sealife which
you seek.
