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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
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.
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.
INON D-180 Manual
Version 1.
October 4, 2003
Copyright 2002, 2003 by INON America, Inc. All rights reserved.
"Clear Photo System"
This filter only lets the non-visible wavelengths pass through.
17
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