Firing SB600 from SB900 commander mode off camera

<p>HELP!! I need to be able to fire my SB600 simultaneously with my SB900 OFF camera. I am using a sound trigger to fire the SB900 flash in commander mode but the SB600 does not also fire. Can anyone please tell me how two set the two flashes up for this function. If I place the SB900 ON the camera everything works as it should. I have tried reading the manuals but they only seem to give instructions for ON camera use, nothing specific for OFF camera. Any help would be greatly appreciated.</p>

<p>The SB-900 has to be the master in order to wirelessly control the SB-600. When the SB-900 itself is off camera and it is not connected by an SC-28/29/17 type cord, it is no longer the master.</p>

<p>When both are off camera, you need to use something else as CLS master to fire both. Which camera body do you have? Some Nikon bodies have a pop-up flash that can work as the master, or you can use an SU-800 as the master.</p>

<p>Hi Shun,<br>

Many thanks for the quick response. I have The D700</p>

<p>Shun, I should have explained the exposure is set to 6 seconds, that is why the flash is operated by a sound switch. (The exercise is to drop a balloon onto a spike, the sound of the balloon exploding sets off the flash - this of course happens in a darkened studio whilst the shutter is open on the 6 second exposure.</p>

<p>I am not sure how you use sound to trigger the SB-900, but can you do something similar for the SB-600? However, you may have trouble to get them to synchronise and cooperate together to provide correct exposure since they are no longer in the CLS mode.</p>

<p>Peter, the easiest way to accomplish what you want is to trigger the SB-600 directly from the sound trigger and use the SB-900 as a dumb optical slave. Dumb slave mode is called "SU-4" by Nikon for no good reason. Everyone else just calls it plain optical slaving. Page D-50 of the SB900 manual tells you how to set SU-4 slaving mode.</p>

<p>There's no need to get the flashes to "cooperate together to provide correct exposure". You take charge of the output power of each flash in manual mode and set the appropriate power ratio by Guide Number, flashmeter reading or trial exposure. All that's then needed is to set the camera aperture for the required exposure. Take one stop off the exaggerated maker's guide numbers BTW. True guide-number of the SB-900 is around 30 (metres/100 ISO) at the 50mm zoom setting.</p>

<p>CLS needs a coomunication between the camera and the master flash and you don't have that with sound trigger.<br>

Trigger your SB600 with the trigger and set your SB900 on the SU04 mode(if available), but you have to set verything manual.</p>

<blockquote>

<p>The exercise is to drop a balloon onto a spike, the sound of the balloon exploding sets off the flash</p>

</blockquote>

<p>The issue is that the two (or more) flashes must be perfectly synchronized. Otherwise, you are effectively doing a double (multiple) exposure catching the balloon bursting in different stages. Most likely the multiple exposure is not the effect the OP wants.<br>

If the control is manual instead of CLS, you can experiment around (without the balloon bursting) to get the flash ratio right beforehand via manual control. However, the perfect synchronization is the difficult part without CLS.</p>

<p>SU-4 mode is a bit more than a "dumb optical slave". It is named for the wireless remote TTL flash controller of the same name which has been around for years but is still available. In addition to a firing signal, it can also provide a quench signal, making the remote flash workable in the auto flash mode 'A'.</p>

<p>Lots of speedlight info in this Nikon brochure - http://www.nikonusa.com/en_INC/IMG/Assets/Common-Assets/PDF/FastTrack_To_WirelessSpeedlights.pdf</p>

<p>Thank you all very much for all your suggestions - I really appreciate your help and comments. I shall have to try them out now. I can see what is being said here re the CLS etc and now that I understand that better I think I shall be able to work something out.<br>

Really appreciate your time guys. Many thanks, Pete.</p>

<p>The SB600 does not have a built-in optical slave sensor and therefore does not have the SU-4 mode. The optical sensor on SB600 works only in the CLS/iTTL/DTTL/TTL mode. So, trigerring first SB600 via baloon or whatever (?), as already adviced, is your option.</p>

<p>If you could get the old SU4 unit, you could use SB600 as an optical remote slave in SU-4 - TTL mode, or in SU-4 Manual mode. Any other optical trigger, like old from Vivitar, Sunpak , Wein, and similar will trigger SB600 remotely, that would work as SU-4 - Manual mode.</p>

<p>Nikon web archives have all relevant manuals for the old SU-4 unit, and for SB600, SB900, and has the "SB800_Techniques.pdf" brochure that explains most/all possible combinations for CLS flashes.</p>

<p>Thanks Frank, I will look into the possibility of getting an old SU-4 but in the mean time will try triggering the SB600 and using the SB900 in the Slave mode.<br>

Regards, Pete.</p>

<p>Just a follow up to all who have contributed. I have tried what Rodeo Joe has suggested and guess what? . . . IT WORKS!!! Many thanks Joe. As they say . . . sorted!!</p>

<p>Thanks again to all.<br>

Pete.</p>