the D-180 Advanced Cancel Circuit (patent pending) effectively reduces the internal strobe’s main flash output with the following benefits:
Conserves the internal strobe’s condenser energy so the internal strobe’s recycle time is shortened, allowing quicker follow-up shots.
Reduces energy consumption so more images can be taken per set of batteries.
The Advanced Cancel Circuit reduces the internal strobe’s second main flash by first telling the D-180 to reproduce (in real time) the camera’s pre-flash, but at a multiple of the actual camera pre-flash output. (e.g., In the case of the C-3030/3040 pre-flash, the D-180 emits its own pre-flash but at 22 times higher intensity.) The actual D-180 pre-flash strength corresponds to the particular camera model’s internal strobe pre-flash intensity.
The purpose and design of the camera’s pre-flash is to illuminate the subject in air, in order to calculate the main flash duration. The camera’s pre-flash intensity and main flash exposure calculation method were not designed to be used in water, where much of the pre-flash’s light is absorbed in the water between the camera and subject. The camera, receiving little reflected light back from the subject, thinks “Oh my, it is really dark out there.” and tells the internal strobe to emit a full discharge, hoping to sufficiently illuminate the subject. So the internal strobe fires a full “dump” of light and releases all the built-up energy stored in its capacitor. It then takes a few seconds for the energy to build up again before another image can be taken.
In contrast, in addition to the internal strobe’s pre-flash intensity, the D-180 calculates its pre-flash based on the fact that the pre-flash must pass through water (not air) on its way to the subject and back again to the camera. When the camera receives more light from the D-180 pre-flash, it does not “think” it is so dark and fires its main flash at reduced output, conserving stored energy in the internal strobe’s capacitor, enabling the strobe to recycle faster, shortening the interval between shots and allowing more shots per set of batteries.
Reference No. 7 “Clear Photo System”The Inon “Clear Photo System” helps produce clearer better images, shortens the camera’s internal strobe re-cycle time for quicker follow-up shots, and prolongs the camera’s battery life.
No Backscatter: The most important function is to minimize incidence of “marine snow” (backscatter). Backscatter is when particles suspended in the water in front of the lens are illuminated by the camera’s internal flash, resulting in a “blizzard” effect of white specs in the image. Or, if the particles are very small, the resulting image may look hazy or out of focus. Clear Photo System works by first placing a visible light cut filter (“Clear Photo Filter”) over the camera’s internal strobe. This filter only lets the non-visible wavelengths pass through. Accordingly, there is no visible light coming from the camera to illuminate the particles and cause backscatter. The D-180 does not need a visible light signal from the master strobe to function.
