Originally posted by BarryE ... I'm planning to use this flash wirelessly using a K-1 for interiors/real estate.
So what are the current options for off-camera wireless triggering of the AF-540FGZ IIso I maintain full auto communication. ...
Another possibility is
the Godox system. They haven't fully fleshed out Pentax P-TTL support with their older models, but all the newer models of gear are coming out in Pentax flavors. The big drawback is you can't use the AF-540FGZ ii in TTL in this scheme, and at the moment, there are no full-sized speedlights for Pentax (the
V1-P is probably going to be the first one) that can do P-TTL on-camera. The only on-camera flash you can use at the moment in P-TTL is the TT350-P mini speedlight.
But here's the good news.
The
XPro-P radio transmitter is $70, and an
upcoming X2T-P will probably be $60.
And you could also use a V1-P or TT350-P as an on-camera transmitter unit. All the speedlights in the Godox system have a built-in radio transceiver.
You can use this on-camera to get TTL/HSS/remote power control from the TT350-P minispeedlight, a V860II speedlight, AD200 bare bulb flash, and AD400 Pro, AD600, and AD600 Pro monolights. You'll get HSS/remote control over the TT600 and V850II speedlights, and the AD600M and QTII monolights. And remote power control over the SKII, DPII, GSII, DSII series plug-in monolights. You also get modelling light control over the monolights. The AD lights are battery-powered, the other monolights are AC-powered.
And the cheapest unit, the Godox TT600 manual speedlight, is US$65, new. Which is less than a Cactus V6II transceiver.
Unlike the Cactus system, there are no P-TTL receivers in the Godox system. And if there were, they and the 350 mini speedlights do not do cross-brand TTL support.
But the Godox system does have TTL on-camera speedlights in it, as well as larger lights. The Cactus RF60x speedlights are single-pin, so cannot do TTL on-camera; and Cactus doesn't make any bigger lights. And the built-in transceivers in the V860II (and the V1) speedlights and the built-in receivers in the bigger AD lights do cross-brand TTL switching that includes P-TTL.
If you need off-camera P-TTL right now, or you have you to use the AF-540FGZ II off-camera, then the Cactus V6II system is probably your best choice. If you can wait, need the expansion option of bigger lights, or you're okay with just having power control and HSS, then Godox may be a decent path.