I recently tried the SB 800 speedlite flash to work wirelessly with my Nikon Z50 mirrorless.
The setup is like this
Pop up the flash on the Nikon Z50, Burst mode NOT on Extended High (H*)
On the Nikon SB800 speedlite flash, set it to work in SU-4 mode. To do this
1. Long press the SEL switch to get into custom mode and
2. Click on the wireless icon and
3. Scroll to SU-4 mode
4. Select it by pressing on it.
Then using the popped up flash on the Z50 fire away. The SB-800 will fire remotely as long as it is, in line of sight of the Z50’s flash. No TTL but one can work that manually on the SB-800. I use manual on the camera. First I get the background exposure on manual without the flash. Then I add the flash and work the aperture to taste to control the flash, or move the flash around to get the correct flash exposure.
Neat trick to use an off camera flash on the Nikon Z50. And you can use any mirrorless camera that supports wireless flash with the pop up flash as main and the off camera speedlight flash as the slave. I haven’t tested this on other brands but the same concept should work with any brand camera & flash as long as remote optical wireless flash is supported on the flash unit, (optical slave). The camera just needs any flash on it to trigger the remote optical slave.
Very innovative. Nicely done.