INON D-2000 Underwater S-TTL Strobe User Manual
Newly developed “S-TTL” is TTL-AUTO. D-2000 is controlled by camera to obtain accurate exposue in which CCD measures D-2000 strobe light coming through camera lens. So S-TTL is free from influence of conversion lens or filters which affects angle of view or f -number of lens. Only the difference from genuine strobe of camera manufactures is that S-TTL employs optical signal instead of electrical signal. The optical synchronous signal is Infrared ray(lR) created by Clear Photo System by cutting visible light from built-in strobe light.
IR enables to catch optical synchronous signal “outside” of transparent housing so water-tight synch connector is not necessary like a strobe which requires electrical TTL signal. S-TTL transmit optical signal to D-2000 through durable multi-core fiber optics. All pre-flash type digital camera is compatible with D-2000 when using in transparent housing. Since S-TTL employs optical signal, in theory, it is possible to have numbers of strobes connecting via fiber optics in TTL-AUTO. S-TTL is ideal strobe system under severe condition since it can freely uninstall underwater, has wide compatibility and has accurate exposure even in multi strobe configuration.
S-TTL is compatible with pre-flash type digital camera. Pre-flash is faint flash measuring exposure value before main flash. In S-TTL system, D-2000 emits pre-flash and main flash same as genuine electrical signal based TTL auto-strobe, which acquires accurate exposure. *In principle, S-TTL is compatible with a non pre-flash type camera. However strobe light may be blocked before reaching to strobe light-sensor on a camera depending on housing shape or conversion lens and unable to calculate correct exposure.
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