Tadpole007

I used the recommendations from Splashdown Divers.com (Intermediate User Settings)  that recommended the AF Assist Light be switched to "Off."  It was in that mode that I could not get the camera to lock on many easy subjects (with the 18-70 mm lense and a +4 diopter).

When I was directed to change the AF Assist Light to "On" at my local SCUBA shop, the D70 was immediately able to lock onto a subject (at least in the pool).  During my next dive trip, I happily got the same results and my problem has been solved ever since.

Please give it a try to see if it works for you also.  Good luck!

Jim

I had the same exact problem and lost some wonderful shots of some large bat rays.  When I took my camera and housing into my local U/W photo pro, he told me to switch the AF-Assist Light from "Off" to "On."  While I don't understand all the technical apsects, this seemed to solve the problem.  Hope this helps!