# 7D built in flash as master showing up in pictures.



## Valvebounce (Feb 23, 2016)

Hi Folks. 
Today I had a task to photograph some paintings / prints with a closeup of the signature to enable easier reconciliation with the valuation catalogue. Some of them were really dark, some behind glass with bright backgrounds causing strong reflections. This was supposed to be a quick and easy task! Hah! : 
So I thought that some might respond to a flash off to one side to enable the picture to be brighter than the background, ideal tool 7D MKII master flash controlling a 550ex flash as slave set to have the only contributing flash be the slave. Page 266 bottom image of the menu, selected the 3rd option starting with disable as option one, or perhaps more accurately the middle graphic symbol. See attachment. My understanding is that the information is transmitted in the pre flash then only the slave flash fires to illuminate the shot, I'm now confused as I was getting light from the master (built in) flash, confirmed this by shooting a mirror and having light from the camera flash plus the slave. 
I also tried my 7D MKI as I was sure I'd used this function successfully previously with the same result. 
Have I missed a setting, or misunderstood the implied notion that the master is not included. 
Any help on this would be most appreciated. 

Cheers, Graham.


----------



## NNature (Oct 19, 2016)

I have the same problem.
It worked on the 7D but not with the 7D mk2...


----------



## Pancho (Oct 19, 2016)

I think that even in this mode, the built-in flash needs to fire to trigger the external flash at the correct sync. Otherwise, how would the external flash know when to fire? A pre-flash before exposure and a delay inside the external flash may be not enough accurate for a 1/250s exposure time...
The power of the built-in flash can be minimum.


----------

