INON S-TTL Explained

The birth of digital fully compatible S-TTL (Courtesy of INON, INC)

INON Strobe Quick Start Guide by: Steve Philbrook

INON Z-240/D-2000/S-2000 strobe supports S-TTL auto exposure simply by setting their main dial to S-TTL position.

Whilst digital cameras quickly took over film cameras for land photography, spread among underwater photographers took longer. Main reason was incompatibility of underwater strobes with digital TTL Auto making hard to benefit fully automatic strobe shooting.
INON is among the first to support digital TTL auto system with S-TTL Auto mode equipped D-2000 strobe and Z-240 strobe.
The proper name of the S-TTL is Optical Synch TTL. The S-TTL enables the strobe to perform in TTL auto exposure as same as genuine TTL strobe from camera manufacture, based on camera’s built-in flash light to use as a signal to transmit it to the strobe. The S-TTL uses the built-in flash not as a light source but as like a controller to trigger the S-TTL strobe.
The built-in flash of a digital camera makes weak flash (pre-flash) before main-flash to calculate exposure. This pre-flash is transmitted through fiber optics to an S-TTL strobe to control the strobe to make pre-flash at a subject. The reflecting light from the subject goes through the camera’s master lens to an image sensor then a processor determines main flash light amount for correct exposure. Finally the built-in flash makes main-flash which is transmitted to the S-TTL strobe to cause main-flash of the S-TTL strobe.

Digital camera’s built-in flash lights are transmitted via an optical fiber to the
S-TTL strobe to make pre-flash and main-flash instead of the built-in flash.

High School Adventure Trip Reviews

High School Adventure Trip Reviews

turtle“I met my best friends and the people who mean the most to me!”
Jake McElmurry, Champlin Park High School

“My scuba instructor (Mark Oestreich) and marine biology teacher (Bob Ameli) not only taught me how to scuba dive, but how to love and care for the ocean.”
Becca Hyman, Chaska High School



“Going on the high school trips were far more than just going on vacation. It opened up my eyes to protecting the life in the water. It gave me a purpose and a passion for the ocean.”
Elle Hagstrom, Andover High School

“My decision to go on the high school trip changed my life. I walked into the airport with a group of strangers and having no diving experience and came back with a new passion and a group of lifelong friends. Five years later and I’m still diving! These trips are organized, educational, and eye-opening. Whether above or below the sea, you will be surrounded by beauty as well as trustworthy instructors.”
Lindsey Peterson, Andover High School