I know www.sagadive.com sells a system/housings to connect two sb800
Hi Ale,
If you want to use i-TTL then only one SB800 can be connected to the camera (with all 5-pins connected). The second SB800 can be fired as slave. However, the optical signals between the strobes can't travel through water, so you have to use an optical fibre for transferring the signals from the master (the one wired to the camera; and by placing the optical fibre in front of the flash head), to the slave (by pointing the other end of the optical fibre onto the signal receiving window).
This works well with transparent strobe housings such as the Fantasea ones.
Thanks a lot Edward and Davichin!!!!!!
Very helpfulll
By the way Davichin, I was in El Hierro covering the open fotosub (as a surface cameraman, the UW cameraman was Gorka Leclerq, from Lanzarote).