The macro nature of the diving around Australia’s largest two cities, also played to the strengths of the optical TTL system. I used the optical TTL system with a pair of Inon Z240 strobes. It worked well and the optical TTL gave accurate and reproducible exposures on typical macro subjects without the need for any exposure compensation. The test shots on the striated frogfish from Sydney Harbour show that the system produced consistent flash exposures, by varying the flash power, from f/20 to f/4.
However, I struggled to get the reliable exposure compensation with the system, which may have been user error! One click on the Inon gave a large under or over exposure. More importantly I was not able to get a significantly different strobe output from the two sides on TTL.
Of course, it is possible to switch over to manual shooting for full control. Initially, I did this by simply switching the strobes onto manual. Perhaps “simply” isn’t the best word. This means change both the mode and power dials on the Inons - annoyingly fiddly. However, when I spotted a seahorse giving birth I learned a lesson that you should also change the camera from TTL to manual. Leaving the camera on TTL slows the shooting rate significantly because with the strobes ignoring TTL pre-flashes, the internal flash fires on full. I missed the opportunity to shoot better images of the seahorse giving birth because I was unable to shoot when I wanted. Most frustrating when an opportunity is hard to repeat.
Thanks to advice from those more experienced than me with optical strobes (praise be, the Wetpixel forums) I learned to set the D700’s built in flash to minimum manual power (1/125th). This guaranteed high frame rates (although I didn’t need them again)! But manual gave me the chance to shoot any creative lighting I wished. Being quite a pain to switch between manual and TTL (four dials changes on strobes and a trip through the camera menu) I stuck with manual strobes, triggered by the optical cables for the rest of my time with the Nauticam. Ultimately I was very happy with the performance of the optical cables.
I feel that only providing the option for a single electronic synch socket is inadequate. I would recommend Nauticam make a dual socket adaptor (Y-shaped) for the single hole in the housing. Anyone wanting to shoot electronically synched strobes, will probably want to shoot two. The optical technology works well, it just does not work with all the strobes I, and many other photographers, want to use. Getting the right light is important in photography.