Thanks for the info. I had gone through this before using a leaf back and my main reason for going the hasselblad route was I supposedly did not need a one shot box for all hasselblad backs, looks like I might still need one.
For the best results at all shutter speeds you need a One Shot box.
The way the one shot box works is this.
The one shot has a release button on it and you have to use it to shoot. It also has a cable release you can plug into it.
So the camera is fired by the control box. The control box gets a 1/15th of a second closed circuit over the flash sync from the camera.
The instant this starts the back receives a closed circuit, but it is from the one shot box and is of the duration of the selected
expose time on the camera and box. (the two have to match).
The box also sends a wake up signal to the back the same time it sends the shuter release to the camera. As the mirror goes up the back
wakes up. This gives you the best quality the back can produce and better battery life as well as less heat in the sensor.
Kapture group just does things the best way with the One Shot 680 control box.