ST-E3-RT won't fire remote flashes when triggered on 1DX

[kmggdc]

My first post to this forum, hopeing to find an answer.

Had a photoshoot yesterday and ran into problems.  Set up was 1DX with ST-E3-RT transmitter firing 5 remote 600EX-RT's.  This was for headshots so all the speedlites were within 12' of the camera.

After about 60 shots, I started to get intermittent flash firing.  I'd have to trigger the camera several times to get the speedlites to actually fire.  I just figured the transmitter batteries were getting low.  However then the speedlites stopped firing completely, no matter how long I waited.  So started looking at what was wrong.  The ready lite was on the transmitter, so I manually pushed it and all flashes fired.  However, when I triggered the camera shutter, nothing.  I removed the flash and reinstalled it; cycled power on and off on both the trans and camera.  Out of frustration and no ideas what to do, I slipped the transmitter off my 1DX (which is only a year old and gets used once every couple weeks) and put on my 5D mkIII and all started working.  

When I started successfully and consistently reshooting I did notice that one of my speedlites was not firing and those batteries had gone dead.  So I replaced them and finished the shoot.  

After packing up and wondering what the issue could be; I wondered if the 1DX somehow can detect a remote flash battery being dead and thus not fire the flashes (some sort of built-in) safety or warning.  However I can't find anything about this or any idea what could have gone wrong.

Any suggestions or ideas is welcome.

Thanks

[diverhank]

Hmm...that's a mystery. I don't have a 1DX so I really don't know whether it would prevent the flash firing.  But if the shutter goes off and the flashes don't then I don't think it's the case that it smartly prevents anything

At any rate, you should be able to see on camera and on the ST-E3-RT if all 5 are linked...maybe one or more dropped off the link due to various reasons (in this case at least one was low on battery --> deduction battery is low on other ones too).  Devices with low battery do funny things...the 5DIII might be a coincidence

[kmggdc]

Thanks, but I could fire manually with ST-E3-RT.   Not sure how the 1DX would know if a speedlite has low or dead batteries.  The more I think about it, I had no flash on "E" channel; only A, B, C, and D were being used.  On the ST-E3 "E" was active but simply no flash on the unit.

Guess I could try and dig into 1DX manual but just haven't found anything about it via internet.

[Waddizzle]

Wild, wild guess. 

What shooting mode were you in?  Was anything set for AUTO?  If so, maybe the camera felt it had enough light?  Or, maybe it was light flicker?

[kmggdc]

without flash the lighting was very insufficient.  I even took a photo of the dark grey carpet to test that.  Images with no flash were essentially black.  Thanks for the thought though.

[Waddizzle]

---

@kmggdc wrote:

without flash the lighting was very insufficient.  I even took a photo of the dark grey carpet to test that.  Images with no flash were essentially black.  Thanks for the thought though.

---

Ah, okay.  They ALL stopped firing.  I had thought it was just the one flash that had stopped.

[diverhank]

There is a possibility that you have simply encountered the auto-power off features of the flashes and didn't know what to do with it.  

Just in case you don't know, each flash has internal settings regarding auto-power off.  For the 600EX-RT, in normal mode, it goes to sleep after 90 seconds.  As a slave, the default time for it going to sleep is 10 minutes.  After they go  to sleep, you need to press the ST-E3-RT test button to wake them up before you can activate them again.  This is per design.  This might be what you encountered.

Changing to the 5DIII is just coincidence. You might have already awaken them at that point so they would work with either the 1DX or 5DIII.

You can go into the flash menu and 

1. turn auto power off all together (C-Fn-01) - not recommended or

2. Change the sleep time to 60 minutes (C-Fn-10) - rechargeable batteries are cheap. I'd go this route.

or you can use the test button to wake them all up after a break from shooting...

[kmggdc]

diverhank, I'll double check that, but I pressed the manual fire button on the transmitter, then tried cycled the 1DX shutter.  Back and forth a few times, went around and reset all the flash sync's and channels (even though they appeared to be working).  The one flash I didn't check was on setting on the floor for a back light and that is the one that ended up having dead batteries.

So to rephase my question; does the 1DX have some sort of detection built in to sense a flash with dead batteries?  Vs the 5Dmk III does not?  If the 1DX does have such a detection, then that would explain the intermitent firing could have been due to that flash cycle time taking longer, before ultimately going totally dead.  If not I'm worried I have a flash shoe issue.

I have another shoot this Friday (I typically use my 5Dmkiii for interior work); but I'll put the 1DX into the set up and try to put some dead batteries in it so see how it reacts.  I like the concept if it does work that way.

In fact when I switched over the 5DmkIII I was a few head shots down the road before I realized that my backdrop flash was indeed dead; so I had to reshoot all those people.

My real hope that nothing is wrong with the camera body.

Thanks

[PLee]

I would just suggest that you clean off the hotshoe on your EOS-1D X. The symptoms you were experiencing are almost certainly related to how the camera body is communicating with the ST-E3-RT.

[kmggdc]

Had kitchen photo shoot yesterday and that was using my 5d Mk III.  Ends up I had the same issue.  Maybe I never noticed it before.  But it seems that when one of the flashes is dead or batteries are slow to recharge; the ST-E3-RT won't fire the rest of the group (at least most of the time).  The camera fires, but not the flashes.

Seems occassionally it will fire because I may have flash that didn't fire (which shows up in my image review); but that could be attributed to communications issues (which does occur from time to time). 

But when this occurs, I put new batteries in the flash and all is good again.

As to my original post claiming that switching camera bodies resolved the issue?  Perhaps since one of the flashes was alread dead, then when I switched camera bodies it only recognized the flashes that were active?  Don't know, but typically I'm on a time constraint and racing against the clock with people waiting for me, so my last 2 events have not been a good environment to experiment.  However I will continue to observice this issue and when time permits in the future, but for now I'm convinced that when a flash is dead in the group; the ST-E3-RT won't fire the group.

I wish someone at Canon could confirm this.  I've read through the manual and don't see any reference to this issue.