Hi Everyone: for macro photography I used my Nikon d800 with the 105mm lens, Nauticam NA-D800 housing with two S&S YDS1 strobes this August for the first time. The strobes were set to TTL, the flash mode was set to TTL, and the flash sync speed was set to 1/250 Auto FP . Many times the sync seems to be going wrong, with a shadow bar appearing in to lower part of the frame. To make it more annoying, it does not happen all the time, so you never know when your strobes are going to "fail" in this way. Anyone has had the same problem? is there any solution that does not imply going into "manual" flash mode? Thanks in advance for any help.