Sorry, Dee, but you missed this one.
The YS-90 Auto is an attempt by Sea & Sea to offer some sort of automatic control to the digital market. It works something like the Ikelite TTL slave sensor, but not nearly as well -- for a couple of reasons.
Every digital camera maker uses a different quenching method. They all read the reflected light and turn off the flash, but none of them do it the same way. The Ikelite sensor reads, not the reflected light, but the camera's flash. It doesn't matter how the camera decided to turn off the flash, it did, and the Ike sensor turns off the external strobe at the same time.
The S&S Auto works like this. It has an eye in the head that reads the reflected light and turns off the strobe. It makes that decision based on the aperture setting on the back (where the power dial is on the DX). You set the dial to the aperture that you have set the camera to. When the proper amount of light hits the sensor, it shuts off the strobe. It does not have to be hardwired. It is designed to work with the fiber optic cable just like the DX
Here's the problem. The light reflected back to the strobe head does not necessarily equal the light reflected to the camera lens. If you're doing this right, your strobe head is way off to the side of your subject, and only partially pointed toward the subject. So, the distance and the angle of the light reflecting back at the strobe has no correlation to the light going to your lens. Also, Sea & Sea is guessing. Does f5.6 on a Canon G3 require exactly the same exposure as f5.6 on an Olympus C-5050? Not likely. The lens is different. The chip is different. The ISO sensitivity is different...you get the idea.
On top of all this, a leading Sea & Sea dealer today told me that Sea & Sea has not delivered the first of these strobes yet. It is in the catalog and on the web site, but no one has seen one yet.
