It should only pop up in Auto or certain scene modes, that's regardless of anything else.
I think he's using it to trigger the Nissin remotely - is there a way of it doing that without popping up?
It appears so..So this isn't about the surprise popping up of the flash and it's about why does it flash?
Another "why does my onboard flash go off when using a flash in slave mode?" thread!
I'm using the flash off the hot shoe away from the camera and the pop up is still flashing. I'm using man mode and ap setting.
The flash, both on board and Nissin are flashing in sync. There is no issue with it when on the camera hot shoe. I'm going to try it in manual mode with the power on the Nissin at various strengths. Sorry to cause all this trouble fellas, all I want to do is use the Nissin to create effects under arches, doorways and bridges.
When firing an off cam flash using Nikon's CLS, you do need the on board flash to trigger, unless you stick a wireless trigger onto the hotshoe and receiver on the flash, or use a hot-shoe cord to connect both. Otherwise the camera is trying to help you fire that off cam flash by popping the built on flash. You can go to the flash menu and set the on board flash to "--" - so it has no effect on the shot.
Sounds like you need some flash triggers.
I have the nissen and a d7000, when in Creative Lighting mode the manual states the inbuilt flash has to be in the raised position even if its turn off in the menu, ie commander mode only.