Nikon D750 and off-camera SB-700 intermittent firing

<p>Hello there,<br>

I'm hoping someone can help me diagnose a problem I had the other night. Here's my setup:</p>

<ul>

<li>Nikon D750</li>

<li>SB-700, off camera in a cold shoe, with (new) Energizer AA Alkaline batteries</li>

<li>Shooting in manual mode, at 1/200 at f5.6 or f8</li>

<li>Flash output was 1/8 to 1/16 depending</li>

</ul>

<p>Now here's what's strange.<br>

I'd be shooting and the flash would be firing, then it would suddenly stop. In looking though the viewfinder, the lightening bolt would go away and I could no longer communicate with the flash. I'd push the shutter and nothing. I had to wait for the lightening bolt to return before I could resume shooting. This might be anywhere for 10 to 15 seconds. Then I could take two or three shots and again before the problem repeated.<br>

Some other notes:</p>

<ul>

<li>I was not shooting anywhere near capacity of the flash</li>

<li>I was always in line of sight of the flash, never being more than 2 or 3 feet away from the unit</li>

<li>The batteries were new</li>

</ul>

<p>So my question is this. Have any of you experienced this before? And if so, how did you solve the problem?<br>

Thank you.</p>

It could be one of a number of things.

1) The flash going into "sleep" mode. There's no AF

wake up signal in a cold shoe.

2) The flash simply having to recycle after 3 or 4 part-power shots. If you're using disposable alkaline cells it doesn't take much use before the recycling time extends into many seconds.

3) Overheat shutdown. I'm not sure if the SB-700 has this "feature", but if so it's a likely explanation.

4) A fault in the D750 that's switching it out of flash mode intermittently.

Having said that. I'm puzzled how the D750 knows the flash isn't available by the lightning symbol disappearing. Optical CLS communication is one-way from camera to flash. In a cold shoe the flash has no way of telling the camera its ready state.

Anyway, what's needed is further investigation to eliminate some of the above possibilities. I suggest you disable sleep mode and overheat protection in the speedlight menu and fit fully charged rechargeable NiMH cells. See if that cures the problem.

You could just keep an eye on the ready light of the flash too. If the flash is taking a long time to recycle then the ready light will show that.

P.S. Check that nothing is accidentally pushing the popup flash down on the camera. That would cause the lightning symbol to disappear too.

<p>If you are controlling the off camera flash via the built-in flash of the D750, then the built-in flash and its recycle time or possibly its overheat protection may be limiting factors.<br>

The flash icon in the viewfinder tells the status of the attached or built-in flash.<br>

They are recommending a separate devise (su-800 or another master flash) for situatuions where a faster recycle time is needed.</p>

<p>Thanks everyone for taking the time to get back to me.</p>

<p><br /> @Rodeo Joe Thanks for the tips about what to do. Perhaps the flash is going to sleep. I will take a look at disabling the sleep option. Off the top of your head, do you know how to do this? I don't ever recall enabling this function in the first place. As for the strobe overheating, I wish it was that simple. But it isn't. I took the flash off the cold shoe and held it close to the camera. I'd fire off two pictures, maybe three, then the strobe would stop working. About 5 ~ 10 seconds later, the strobe would fire again.</p>

<p>In looking at the back, the temperature meter never rose or moved. Also, at first I thought you might be right about the popup flash being accidentally pushed down a bit, but when I took did my test of holding the flash close to the camera, and still experiencing the same issue, I realized that couldn't be the case.</p>

<p>@Kari Oinonen Thanks for the help. Interesting about the flash icon in the viewfinder relating to popup flash. Now I'm wondering if the issue isn't the SB-700, but rather the recycle times on the popup flash. But that doesn't make sense as I have the power on the popup flash turned way down.</p>

<p>What has happened to me a least once: I was in a hurry trying to take that shot. The buil-in/ popup flash did not fire. I tried several times with no luck. Finally I turned my hat backwards and it worked. - The peak of my cap was tilting the popup a bit to make it unactive :-)<br>

Anything can, and will happen.<br>

And one another thing to consider. The master flash mode - unless using a flash value lock (which can be recommended where relevant) - uses much more juice than just the indicated flash output value. This is because master flash is telling the other flash (groups) what to do before each exposure. This communication uses somewhat juice.</p>

<p>@Kari Oinonen<br>

<br />What is this 'master flash mode' you speak of? I am not familiar with it. Right now I am using the pop-up flash as a commander to command the SB-700.</p>

<p>What is strange though is that I was able to repeat the issue while on-site by taking the flash out of the cold shoe and firing my D750 in close proximity to the flash. The flash would go off two or three times before shutting down for 5~10 seconds. Then the lighting bolt would return to the camera viewfinder and the flash would fire two or three time before the whole process would repeat. In this instance there was nothing interfering with the pop-up flash.</p>

<p>Sorry, I was not using the proper Nikon term. Master = the unit that controls other units = commander in Nikon terminology.<br>

Test what you can do with the suggested FV-lock. It seems - based on your tests - that the pop-up flash needs too much power and thus recycle time in commander mode. Unfortunately I do not currently have an possibility to make that test.<br>

If you set the FV-lock, the systems makes only one preflash-measure -cycle when activated. Then the measured values are used for the the following exposures. Additional preflashes are not needed, you get less flash blinking before following exposures, delay due to commander preflashes is eliminated and power is saved too.</p>

<p>@Kari Oinonen<br>

Thanks for the help. I do have a follow up question though. What is the FV-lock? I am not familiar with this term.</p>

<p>To date, what I have been doing is using the pop-up flash on my D750 to act as the commander. I am under the impression that if I turn this flash way down that it can be used to trigger the SB-700.</p>

<p>But in writing with you here, it does sound like the pop-up flash is drawing too much power, thus preventing the SB-700 from firing. That would explain the issues with the cycling time and the flash/lighting bolt I'm seeing inside the display. I'll have to see about turning the on-board flash down to nothing. Or at least as having it output as little power as possible.</p>

<blockquote>

<p>a flash value lock (which can be recommended where relevant) - uses much more juice than just the indicated flash output value.</p>

</blockquote>

<p>= FV lock. See the manual if needed. FV lock should be available with your setup.<br>

It helps - somewhat - if you turn down the popup output, but still the commander flash pulses may take too much juice. When you use FV lock you do the commander-measurement (preflashes) action only once and the following pops of the SB700 are based on those values.<br>

Overall you are using the popup less, so energy is saved and the preflashes are avoided.</p>

Thanks Kari.

I haven't been doing any off camera flash recently so I'm not sure if we have managed to solve the issue. I turned off flash

going sleep feature, so hopefully that will solve my problems.

What I need to do is try some off-camera shooting again to see everything is working fine.

Hi guys,

I've got the same kind of issue with my D750 + SB-900 in CLS

But for me, the camera just don't shutter at all oO

Sometimes I have to wait 10-15s and I can't even shutter...

I used the CLS for long time on my D7000 with SB-700 and I never got this problem...

I've spent the last hour testing and apparently it's caused by the overheating security on my built-in flash !

I usually set the built-in flash so it doesn't affect the final picture (it's firing a tiny bit before the actual picture to don't appear), bu I think this make it fire at full power.

When I simply set it in Manual mode and on 1/128, I can shot much more before I get the same issue.

I have to try again with my FM transmitter to test it, but I guess I won't have the same problem (only SB-900 not firing when it's recycling)

If you're only interested in manual flash control, then forget CLS/AWL altogether and use a set of cheap radio triggers.

After losing a couple of what should have been good pictures through the off-camera slave not firing, I gave up on CLS years ago. Cheap radio triggers have never lost me a single shot - AWL (Amateur Wonky Lighting) has lost me several too many.