Originally posted by pschlute
When using wirelessly do not use Contrast control sync mode. That is only for wired connection.
Originally posted by stevebrot
Are you sure? My understanding is that is only true when using a mixture of built-in and external flash when the built-in does not support P-TTL master. With a P-TTL external flash on the hot shoe and a second P-TTL external flash as remote, contrast control should be possible. (See K-1ii user guide, page 112.)
I did some more research on this as well as attempting to set up for contrast control on my K-3 using the on-board flash and my Sigma EF610DG Super. Yep, not an option for optical wireless on the Sigma unit. It was then that it dawned on me

that the contrast control has historically (pre-P-TTL) been "Contrast Control Sync" in the context of real-time quench for OOF TTL. In that context, the built-in flash and the hot shoe are to start together, but quenched differently to different exposures based on the TTL metering. The same strategy is inherited with P-TTL bodies with the Sigma flash that aimed to AF540FGZ emulation. That said, the rules might be different with two AF360FGZii using P-TTL optical wireless.
Steve