If you already own a Subal housing, you know that they are a stellar example of craftsmanship and thoughtful design. Their outstanding ergonomics and broad line of ports make them a joy to use and set a new standard for flexibility, no matter what your favorite discipline.
In addition to all of the well known features, Subal housings have a unique option, allowing the user to configure one and/or both strobe bulkheads for use with either manual strobes or TTL (conversion circuit required) strobes. Here's how to set this option up correctly:
Locate the bulkhead distribution circuit board located top-front-center inside the housing.
Note that on each side of this circuit board, there are two female connectors. Upon closer inspection note that the inner (nearest the center of the housing) female connector has 5 pins, while the outer (nearest the handles) female connector has only 3 pins.
Manual mode means that the user manually controls the output of the strobe via the output settings on the strobe. We often refer to this mode as TTB (thru the brain) strobe control. While not as sophisticated as TTL, manual mode often offers more finesse and control over the output and final image than TTL, and is not as difficult to learn as many would have you beileve.
If you are using strobes in manual mode (without an external TTL conversion circuit) connect the male connector from each bulkhead to the outer (3-pin) female connector on the distribution circuit board.
The three pins are all that are required to successfully fire your strobes in manual mode.
TTL (thru the lens) exposure control refers to the ability of a camera to analyze the lighting of a scene, communicate with strobes, and control their output to obtain proper exposure. In the dark (pre-digital) ages of photography, cameras had the ability to measure the light reflected from a subject as it was bounced off of the film plane. Not so with digital cameras, much more hocus pocus is needed, but the end result is the same: automatic exposure control.
TTL operation with most housings requires a conversion circuit to translate the camera's proprietary TTL flash output signal (i-TTL for Nikon and E-TTL for Canon) into the Nikonos protocol that underwater strobes understand. Popular options include offerings from Heinrichs Weikamp, Sea & Sea, and Ikelite. The conversion circuit that you choose will depend on a number of factors including budget, brand of strobes, and shooting style. Feel free to contact us for an evaluation of your setup and recommendations about TTL conversion circuits.
If you are using an external TTL conversion circuit (not included with Subal housings) to achieve TTL, connect the male connector from each bulkhead into the inner (5-pin) female connector on the distribution circuit board.