Originally posted by CPhoto I've read that with the Cactus V6, I would also need a V6 attached to my flash unit for them to communicate with each other. Is this the same with the PocketWizard?
Yes. Wireless flash of the radio frequency sort requires both a transmitter on the camera and a receiver on the flash. The Cactus units are actually transceivers, meaning they have both the transmitter and receiver in the same unit. You set one to 'transmit' and the other to 'receive'. Gives you a little more flexibility in some situations.
The Cactus v6 units also give you the ability to control flash power from the camera which I do not think the PocketWizards do. But in your situation that might not make any difference since you can just tell your assistant to adjust as you need.
Neither unit will be more 'compatible' with Pentax, they are just going to transmit the fire signal. The Cactus will likely be much cheaper, the PocketWizards are used in many studios so that might be a consideration if you use those facilities.
---------- Post added 03-13-16 at 09:35 PM ----------
Also if you go with the Cactus, consider the Cactus RF-60 flash which contains one transceiver unit and thus saves you the cost of a receiver on the flash.
Adorama is currently running a special with one V6 transceiver and one RF-60 flash for $169