Abstract: The Ikelite iTTL controller works great. But if you prefer, just press two buttons and the controller switches to manual mode. Either way, it's super easy to use.

This TTL system really rocks! I get perfect lighting under almost every imaginable condition e.g. shooting under reefs, against the sand, against the sky, with cloudy skies, sunny skies, etc. without changing any camera settings during the dives!

New photographers should be able to get good shots without knowing a whole lot about what they are doing i.e. use the recommended D70 settings, point, and shoot.
Experienced photographers should be able to spend more time finding and composing subjects and get more keepers.

And I REALLY like the right angle bulkhead connector. I didn't think there was a real problem with the design as it was. But turns out, I was wrong. Wrong in the sense that my updated rig looks tougher and more professional and I feel better about it.

Description: The following information is from the Ikelite web site.

Conversion circuitry in the housing allows the latest Ikelite DS-50 and DS-125 SubStrobes to provide real iTTL flash control as dictated by the Nikon D-70 camera, providing standard iTTL for matrix, center-weighted and spot metering. All of these settings work well. The circuitry is powered by the SubStrobe which must be attached with a single #4103.51 or #4103.52 dual sync cord.

The circuitry powers up automatically when the strobe is turned on, lighting the yellow LED beside "TTL" on the label indicating the system is ready to use.

The arrow buttons beside "Mode" on the label provide four 1/3 f/stop increments of over or under flash compensation. This compensation is added to or subtracted from any compensation entered into the camera. Plus 1/3 f/stop is shown in this photograph.

Push both buttons simultaneously for one second to change from iTTL to Manual strobe control. The yellow LED beside "M" on the label illuminates, and the red LED shows "F" indicating full power. The arrow buttons access the eight manual power settings in half/stop increments.

Photograph shows sync cord attached to the new right-angle bulkhead.

Note: The iTTL circuitry requires the latest level of DS-50 and DS-125 strobes to work properly.

DS-50 SubStrobes with Serial Number below 63,850 can NOT be updated to operate correctly with the latest TTL conversion circuitry. DS-50 SubStrobes with Serial Number between 63,850 and 69,999 operate well with the latest TTL conversion circuitry, but require a $50 update to provide optimum performance.
DS-125 SubStrobes with Serial Number below 2,500 require a $150 update to operate with the latest TTL conversion circuitry. DS-125 SubStrobes with Serial Number between 2,500 and 4.999 operate well with the latest TTL conversion circuitry, but require a $50 update to provide optimum performance.

Settings: I started with the settings I used for about a year while waiting for iTTL. But I quickly realized that I wasn't getting the most from my strobes this way. So I increased my F stop from F8 to F11 to put more punch in my pictures since with iTTL I can use more aggressive lighting.

When using the Ikelite iTTL controller, set the strobes to TTL mode for use in either TTL or manual mode.
TTL Mode - Use Center Weighted Metering set on the camera and -1/3 EV to -2/3 EV Flash Compensation set on the housing. When shooting, I leave Flash Compensation on the housing set to -1/3 EV unless I am shooting highly reflective subjects e.g. white sand and shiny fish. Then I use -2/3 EV or even -1.0 EV. Here your best guide is the LCD monitor set to highlights mode where you can easily see if you are blowing out the highlights.
Manual Mode - Leave metering set to Center Weighted though it has no effect in manual mode. Then, as a starting point, set the manual controller on the housing to - 1.0 EV which is equivalent to 1/2 power on a DS 125 strobe. From here you can increase or decrease the power to your strobes with the up and down buttons on the housing. As with iTTL, your best guide is the LCD monitor set to highlights mode where you can easily see if you are blowing out the highlights.