The picture above was taken at about 60' underwater, about 1500-2000 feet from the main entrance. Brad Reynolds used a Nikon D-70 with twin Ikelite Substrobe 400's to light the foreground. If you look closely you'll see that a 3rd Substrobe 400 is strapped between my tanks and illuminates more depth of the cave... also making my fins stand out to look like I have a blue tail. My own camera which you can see in the picture (a Canon 300D with two Sea&Sea YS-90's) was malfunctioning that day; I later discovered the problem was a flooded connector which shorted out the TTL flash adapter card. This problem alone took me about 2 months and 30 dives to figure out.
If you're a certified Cave Diver and are going to be in Cozumel during the winter months October '07 thru January '08, drop me a message.. Hot-doggers take note: I'm more interested in safety and good planning than I am in extreme distances, longest bottom time or unwarranted risks.
Cheers! Safe diving to you...
--Alexander