This is very preliminary, but wanted to get this out to the folks that are struggling getting EFCS and flash to play together.
My setup is a Stackshot controller running a modded THK 20 rail, I run the controller from Zerene. The D850 is triggered directly thru the Stackshot controller with a cable I made that goes from RCA plug (Stackshot side) to the standard Nikon multiple pin connector. I used an eBay remote button and added the RCA plug and cable to the connector. This was my standard cable I use for the D800, D500 and D850 bodies with the Stackshot controller.
My lighting setup is 5 manual studio strobes that are set for optical triggering for this experiment (they are normally also RF triggered but this was not used). A seperate Flashpoint XPLOR 600 studio strobe was used as an optical trigger (later I'll incorporate it into the actual setup, but for now just used as a trigger for the other strobes). The XPLOR was set to manual at 1/256 power and RF triggered from the Flashpoint R2 hot shoe transmitter. I used the delay mode in the XPLOR and set this to 0.38 seconds (after much experimentation). The R2 is not on the camera hot shoe and is triggered by a sync cable that is wired to the same cable that triggered the camera (Stackshot cable to Nikon connector), the cable is wired in parallel with the camera trigger from the Stackshot RCA plug.
The D850 is set to Live View with EFCS, Shutter Delay Exposure of 0.2 seconds and an shutter of 1/10 second.
The idea is that when an exposure trigger is issued from the Stackshot controller to the camera, this also triggers the R2 transmitter which sends a RF signal to the XPLOR strobe. The strobe waits a predefined amount (0.38 second in this case) and fires a flash which triggers the other manual flash for the exposure. I don't need to use the RF trigger except I don't have the right connector for the XPLOR external trigger now, but have the proper connectors for the setup as I described.
Lots more details on this, and why it works and so on, but for now this is all I can post.
The Yellow connector is the RCA plug for the Stackshot controller, the Black and Silver is for the Nikon, the other two are for triggering the RF transmitters I have. Thin barrel plug is for Neewer 433MHz and other is for Flashpoint R2 trigger (standard sync plug). Don't worry about the diode, this is for older Nikon bodies, not needed. Just simply wire up the cables in parallel with the Stackshot output and you are good to go. Be very careful you don't short out things and there isn't much space for all the extra cables (originally it only had the Nikon cable as it's a Nikon remote switch!), very tight wiring. This remote switch comes in handy since you can fire the camera and strobes by just pressing the button (shown locked in Red position) while fiddling with the setup.
More to come later.
Best & Happy New Year,
Mike



