Originally posted by Kenntak I would like the ability to use the flash off the camera, and remotely trigger the flash and the camera.
In terms of radio triggers, I recommend the
Cactus V5. They are slightly more expensive than the cheapest, but can be used with a vast range of flashes and allow some control over which flashes fire from the camera.
They work with Pentax, including the max. Sync speed, without any tricks required.
The Yongnuo 560 III has a built-in receiver, though, so either get a compatible trigger, or another (cheaper) flash.
You may not need radio triggers if you are only considering small setups, avoiding bright sunlight. I'm pretty sure the flash you are considering has an optical slave mode, so you can trigger it with the pop-up flash or an on-camera flash.