High speed sync

churin

I set the control for manual mode, wide opened f stop, cranked up shutter speed for way above 1/250 (1/2000~5000) and triggered the shutter and strobe.
It resulted in over-exposure. It appeared that when I adjusted the shutter speed higher, exposure compensation was automatically pulled down to minus side and that the actual shutter speed is much slower. I noticed that the shutter speed was reset to 1/50 or so after firing the shutter which appeared to be the speed actually used.
Model is D850.

Ton14

Nikon Z6 - with the Yongnuo YN685 triggered via YN622N-TX, no problems with HSS. The maximum Nikon Z6 syncspeed is 1/200 and in the menu set to 1/200s (Auto FP)

As you describe it, it seems that this setting in your d850 is not correct, be sure it is set to AUTO FP.

churin

Yes, that setting - in my case 1/200s (Auto FP) - is included in my initial settings.
I wonder what else could be wrong.

Ton14

Strange, I try to think along. What happens if you put the camera in S mode with a HSS shutter speed. My flash did not switch to HSS and gave a black image, but switched to HSS the second shot. I set the flash and trigger on ITTL.

Pistnbroke

You need to select FP (flash programme) 1/250 in the menu on a D 850. Leave it like that for all situations

TriShooter

Pistnbroke said:

You need to select FP (flash programme) 1/250 in the menu on a D 850. Leave it like that for all situations

I echo selecting FP is essential. Nikon, unlike other manufacturers cameras, does not require tweaking of HS. If you set the Flash to FP and select "Manual Mode" all should be fine. If you use Program, Shutter or Aperture Modes, over-exposure will result because the camera is setting itself to shoot in the light it sees before you fire the camera with the additional light from the flash.