Originally posted by paulster The Acon R930 is the only wireless P-TTL transmitter on the market. The interface is horrible (morse code and flashing LED sequences), but it looks like in a simple one-flash situation where you're controlling it from the camera it would just work right out of the box.
I purchased the ACON. It took a bit of trouble to get it working with Pentax as it was delivered with the wrong firmware and it took many tries to get the correct version installed. Once in, however, the operation is relatively simple: 1) install transmitter on camera hot shoe; 2) install any Pentax-system pTTL flash* into the receiver hot shoe; 3) turn on the four devices this sequence: transmitter, receiver, camera; flash. Now, just point & shoot and you have radio-controlled wireless pTTL. If you want to change the basic pTTL operation, that is a pain involving blinking leds and a sequence of steps impossible to remember unless you do them daily.
* I experimented with a Pentax 360 II and several Metz units, and all seemed to work properly.