# Optical slave issues with Nikon SB-900 speedlights.



## dmac802 (May 12, 2014)

I'm having an issue getting my Elinchrom BX500ri strobes to trigger the speedlights using the optical slave feature.  I have 2 SB-900's and both are set with the SU-4 option to the "on" position.  The sb-900's trigger each other when one is set to the "on" position and the other to the "remote" position.  The sb-900 also can trigger the strobes via an optical slave feature in the strobes.  What I can't do is get the stobes to trigger the speedlights.  Any ideas?


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## table1349 (May 12, 2014)

Try this: Nikon CLS - SB-900 SU-4 Mode

The optical sensor is on the left side of the SB-900, by the battery  door, so make sure that the main body is arranged so that this is  positioned to receive the light from any other flash.


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## dmac802 (May 12, 2014)

gryphonslair99 said:


> Try this: Nikon CLS - SB-900 SU-4 Mode
> 
> The optical sensor is on the left side of the SB-900, by the battery  door, so make sure that the main body is arranged so that this is  positioned to receive the light from any other flash.



I did that.  Shot it right at the sensor and it didn't trigger


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## table1349 (May 12, 2014)

Are they in manual mode?


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## dmac802 (May 12, 2014)

yes.  The 2 sb-900's will work together...one triggered optically by the other one


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## table1349 (May 12, 2014)

Got me then unless the Elinchrom flash duration is to short for the SB 900's to detect.


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## WayneF (May 13, 2014)

dmac802 said:


> I'm having an issue getting my Elinchrom BX500ri strobes to trigger the speedlights using the optical slave feature.  I have 2 SB-900's and both are set with the SU-4 option to the "on" position.  The sb-900's trigger each other when one is set to the "on" position and the other to the "remote" position.  The sb-900 also can trigger the strobes via an optical slave feature in the strobes.  What I can't do is get the stobes to trigger the speedlights.  Any ideas?



Wow!  That all sounds very correct, and thus mysterious.  I have SB-800s instead of SB-900s, but SU-4 mode should be easy as pie (you will want its Manual setting instead of its Auto setting).   SB-900 seems to complicate the menus a lot, since there is actually no Master/Remote relationship for SU-4.  The way the SB-800 SU-4 works, if if sees a flash, it triggers.  If hot shoe or PC triggers it, it triggers.  SU-4 is always both master or slave.   I think SB-900 simply already had that visible switch they had to deal with.   

SU-4 is very sensitive, works at 120 feet or more  Since it is triggered from full working power level of others, then in a normal living room, it will trigger anywhere, regardless of blocking obstacles.

 I would double check that both actually were in SU-4 mode (custom menu, manual page C22).  Sounds like it is not acting as if they are?


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## dmac802 (May 14, 2014)

WayneF said:


> dmac802 said:
> 
> 
> > I'm having an issue getting my Elinchrom BX500ri strobes to trigger the speedlights using the optical slave feature.  I have 2 SB-900's and both are set with the SU-4 option to the "on" position.  The sb-900's trigger each other when one is set to the "on" position and the other to the "remote" position.  The sb-900 also can trigger the strobes via an optical slave feature in the strobes.  What I can't do is get the stobes to trigger the speedlights.  Any ideas?
> ...


  Thanks Wayne. I did just check and they both are on SU-4.


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