The cameras provide automation that allows TTL strobes to simplify underwater photography by preventing overexposure by the strobe. When the camera sees enough light for proper exposure, it instructs the strobe to stop flashing.

Flash exposure depends on subject distance and reflectivity. Manual strobes require estimating this correctly and setting power accordingly for each photograph. TTL strobes allow the camera to do this automatically while you concentrate on available light exposure and composition.

The ratio of flash to available light can be changed with the exposure compensation feature of the camera. Setting the exposure compensation applies this preference to all subsequent photos.

TTL systems work very well underwater, and are certainly easier and less frustrating than constant trial and error manual exposure. Our DS-50, DS-51, DS-125 and DS-160 strobes duplicate the automatic exposure dictated by both digital and film type cameras.

Manual Strobes and/or a manual controller do offer certain advantages. Some of the digital cameras feature a pre-flash of such short duration that duplication by an underwater strobe is difficult. If the pre-flash of an underwater strobe is too different, the camera may not provide proper exposure.

Maximum intensity will be obtained with a manual controller. When the small camera flash has produced its maximum output and stops flashing, the TTL Sensor will quench the underwater strobe. This will usually occur before the more powerful underwater strobe has produced its maximum intensity.