topic Re: 600ex-rt slave flashes randomly stop firing - please help! in Speedlite Flashes

600ex-rt slave flashes randomly stop firing - please help!

PhotoMouse — Tue, 07 Mar 2017 02:02:46 GMT

I've scoured the interent trying to find a solution for the problem I'vve been having and I can't find any posts where people are having the exact problem I am. I'm hoping maybe someone on here has had this problem and might be able to propose a solution. Thanks in advance for any help!

I have 4 Speedlite 600EX-RTs I've been using for about the last 2 years with very few issues until recently. When shooting events I typically use two on cameras (5d Mark III's) and two as slave flashes for room lights. Everything will be working fine and then at some point I look down and realize my room flashes are not firing. The on camera flash will work and the link light will still be green but the slave flashes won't fire until I power off the master flash, then they will start working again for a while until they randomly stop firing. Usually during something important like a speech or the hora.

Just for clarifcation, the ID #'s are all set the same, I keep them all on auto channel, I'm using newish eneloop batteries and I feel like the problem starts too early in the day for it to be battery related. 99% of the time I am on manual across the board and my power on the slave flashes is never more than 1/32 or so.

Any suggestions would be greatly appreciated!

Re: 600ex-rt slave flashes randomly stop firing - please help!

diverhank — Tue, 07 Mar 2017 04:26:40 GMT

I haven't encountered this problem myself. There are a couple of things I can think of:

1. Not sure why you choose to use Auto Channel. I'd manually set the channel for your 4 flashes. This eliminate one potential problem with communication. A middle channel seems to be a safe bet. You can also check for an optimum channel ahead of time.

2. Cfn 10 specifies the time the slaves would auto shut off - either 10 minutes or 60 minutes. I'd choose 60 minutes. Cfn 11 allows either 1 hour or 8 hours as the time the slave units will wake up from auto power off when you press the Test button on the Master unit. Once a slave goes asleep, you need to wake it up by pressing the Master Test button or risk failure on the first shot.

Re: 600ex-rt slave flashes randomly stop firing - please help!

PhotoMouse — Tue, 07 Mar 2017 13:40:03 GMT

Thanks for the reply! I've already got both those custom functions set and it happens in the middle of shooting so I don't think the slave flashes are going to sleep.

I've been using auto channel bc according to the manual they are supposed to automatically choose the best channel when you use auto. I've always used the flashes in this manner and have never had any problems until recently which is a why I'm at such a loss.

Any other thoughts?

Re: 600ex-rt slave flashes randomly stop firing - please help!

RobertTheFat — Tue, 07 Mar 2017 13:55:55 GMT

@PhotoMouse wrote:
Thanks for the reply! I've already got both those custom functions set and it happens in the middle of shooting so I don't think the slave flashes are going to sleep.

I've been using auto channel bc according to the manual they are supposed to automatically choose the best channel when you use auto. I've always used the flashes in this manner and have never had any problems until recently which is a why I'm at such a loss.

Any other thoughts?

I wonder whether the fact that there are more rf devices in play than are ever simultaneously used might confuse the external flashes about which channel is in use. Why not run some tests with the channel manually set, just to rule out the possibility.

Re: 600ex-rt slave flashes randomly stop firing - please help!

TCampbell — Wed, 08 Mar 2017 16:26:58 GMT

You can ask the flash to 'scan' and provide a report of what it thinks is the best channel (it generates a graph showing how much chatter is on various channels). I usually use this to try to find a relatively clear channel and set all the devices to use those.

One other thing...

You mentioned you have two on-camera flashs and two off-camera flashses... is it always the very same on-camera flash unit that you have to reboot to clear the problem? e.g. if you swapped on-camera flashes with the other camera, does the probelm go away?

It's entirely possible that there is something flakey about that particular flash unit.

It's easier to fix when you have something that can reproduce the problem on-demand. When it happens randonly (nothing you can find will make the problem occur) then those are more difficult to trouble-shoot... which is why I might suggest just trading flashes with your other camera to see if the problem follows the specific flash unit.

If the problem happens regardless of which flash is the 'master' then my guess would be it's environmental (radio frequency interference, etc.) But if the problem follows just one specific flash then of course that would point to a flakey flash that should be serviced or replaced.

Re: 600ex-rt slave flashes randomly stop firing - please help!

kvbarkley — Wed, 08 Mar 2017 17:22:55 GMT

Could it be getting confused having two masters? Does it happen if the other camera is off?

Re: 600ex-rt slave flashes randomly stop firing - please help!

georgezinser — Mon, 22 Jan 2018 13:45:27 GMT

dont know if you figured it out but i have the issue as i found that it was the djs wireless dmx lighing as they are 2.4GHZ on the same band as the flashes. this is the 3 time i ran into this and i had to break out my pocket wizards and everything was fine with them as thy are on the 300MHZ band

Re: 600ex-rt slave flashes randomly stop firing - please help!

RobertTheFat — Mon, 22 Jan 2018 14:18:42 GMT

@georgezinser wrote:
dont know if you figured it out but i have the issue as i found that it was the djs wireless dmx lighing as they are 2.4GHZ on the same band as the flashes. this is the 3 time i ran into this and i had to break out my pocket wizards and everything was fine with them as thy are on the 300MHZ band

Wouldn't using a different channel in the 2.4GHz band have had the same effect?

Re: 600ex-rt slave flashes randomly stop firing - please help!

georgezinser — Mon, 22 Jan 2018 14:29:43 GMT

I tried this but the output power for the dmx lighing is more powerfull and you get inerferance. i also had this happen when a powerfull acess point system was at a hotel venue as the wifi is on 2.4GHZ. 2.4GHZ is very congested frequency in the US. im starting to run into inerferance more and more. when they do work thy work great.

Re: 600ex-rt slave flashes randomly stop firing - please help!

RobertTheFat — Mon, 22 Jan 2018 14:50:52 GMT

@georgezinser wrote:
I tried this but the output power for the dmx lighing is more powerfull and you get inerferance. i also had this happen when a powerfull acess point system was at a hotel venue as the wifi is on 2.4GHZ. 2.4GHZ is very congested frequency in the US. im starting to run into inerferance more and more. when they do work thy work great.

My WiFi expertise is a bit dated. but it used to be the case that most consumer devices were set to default to one of two or three channels (I believe 6, 11, and possibly one other). Since most users wouldn't bother to change from the default, those channels would be very congested. So the trick was to choose a channel in the trough between two of the defaults, thereby minimizing interference. You might try that if you haven't already.

Re: 600ex-rt slave flashes randomly stop firing - please help!

marco9394 — Mon, 03 Sep 2018 17:33:49 GMT

Unfortunaly I'm on the same boat. I use a 5d4 with a 600ex-rt and 6D with ST-E3-RT, 2x 600ex-rt as slaves. I run channel scanning and select the best channel at the site everytime. Sometimes they would work an entire wedding without a problem but sometime I would set them up at the reception and they would work for a few series of firing then stop working completely on both cameras. Usually is right after taking a few mins break, they wont fire at all until I cycle the masters on/off. I do noticed it happened more often with one particular DJ who has multiple wireless systems running at the same time like mics & LEDs.

It is so frustrating and makes me thinking about other system that would do better with interference.

Re: 600ex-rt slave flashes randomly stop firing - please help!

Pranabyjonesie — Tue, 18 Sep 2018 14:28:14 GMT

This absolutely happens to me quite often during an important shoot. Sometimes when it starts working again there seems to be no rhyme or reason. I thought maybe it was the zoom setting but yesterday that didn’t help. I had to forgo using the flashes and it was very disappointing. New batteries. Same manual channel. Same wireless. Green light, but won’t trigger. Tried camera in manual or AV mode. Nothing. Manual trigger works. I hope we find help! I’ve also looked all over the web and watch the same tutorials on how to “easily” set up - and I get it, but something is wrong here.

Re: 600ex-rt slave flashes randomly stop firing - please help!

wq9nsc — Fri, 05 Oct 2018 14:57:00 GMT

Canon's wireless flash control operates on 2.4 Ghz. which is a VERY heavily used part of the RF spectrum. Although the IEEE provides more detail about the spectrum, Wikipedia is sufficient to provide an idea of the level of pollution and crowding in this part of the spectrum: https://en.wikipedia.org/wiki/List_of_2.4_GHz_radio_use

Unfortunately this is a problem for many devices and it is one of those undesired side-effects of using political appointees instead of scientists and engineers in the various world regulatory agencies. Courtesy of a new garage door opener I now have to drive my Cadillac ATS a few hundred feet down the driveway so that the TPMS system will properly reset when I change between summer and winter wheel/tire sets because of co-interference between the door opener and tire pressure monitoring system. It is a problem that has continued to get worse instead of better especially because it is coupled with a rapid increase in the number of unintentional RF radiators (i.e. switching power supplies, digital controllers, etc) which produce RF pollution as a byproduct of their normal operation. In addition to specific interference between two devices operating on exactly the same frequency there is the more general problem that the sensitivity of receiving devices is reduced by the number of transmitting devices in the same general location and frequency range. And while your flash is frequency hopping to try and find a clear spot other devices are doing the same so results during a single event are likely to be somewhat random as a formerly clear spot is suddenly being shared with other devices that have chosen your frequency as a possible solution.

Wireless flash control is so time critical that typical measures used to handle communications interference (like multiple retries) are unworkable. At this point for a critical event I wouldn't count on a wireless flash system being practical unless you have a chance to pretest in that location under the exact conditions that you will shoot and that isn't practical for a wedding reception or similar event where entertainment AND guests are likely to bring in stuff that creates a problem. Think of how many guests are carrying around Bluetooth enabled devices which are operating on the same slice of spectrum as your wireless flash. The old infrared system was limited and also experienced some interference but it may well be more reliable in many venues than the more modern RF system.

You can improve your chances of success by locating the controller and slaves as close together as possible. The smart controllers in most wireless devices will transmit at their maximum design power but this will drop as battery voltage drops so it will also help to keep the voltage supply to the various components as close to maximum charge as possible. Fresh batteries to start and changing during an event can help make the system more robust.

Rodger

Re: 600ex-rt slave flashes randomly stop firing - please help!

nuzeman — Wed, 12 Aug 2020 12:28:06 GMT

I'm shooting with a Canon 5d mark IV. I've never had an issue before until today. I have 2 600ex-rt II's. I have a St-e3 transmiter as a master. Green sync lights on all devices. I'm outside on my deck. I've tried changing the channel to auto, and other channels, even changed the ID a few times. I've done ETTL and manuel. All work fine for a few minutes then I get the red unsynce light on the units. If I trun off the St-E3 and both speedlights soemtimes it resets and I can start firing again..then it happens all over again. There is a lot of neighbors close in all directions. I wonder if there is something interefereing? I had this setup for 4 years and never experienced this. Any new information would be most helpful

Thanks

Jon

Re: 600ex-rt slave flashes randomly stop firing - please help!

RobertTheFat — Fri, 14 Aug 2020 13:04:08 GMT

@nuzeman wrote:
I'm shooting with a Canon 5d mark IV. I've never had an issue before until today. I have 2 600ex-rt II's. I have a St-e3 transmiter as a master. Green sync lights on all devices. I'm outside on my deck. I've tried changing the channel to auto, and other channels, even changed the ID a few times. I've done ETTL and manuel. All work fine for a few minutes then I get the red unsynce light on the units. If I trun off the St-E3 and both speedlights soemtimes it resets and I can start firing again..then it happens all over again. There is a lot of neighbors close in all directions. I wonder if there is something interefereing? I had this setup for 4 years and never experienced this. Any new information would be most helpful

Thanks

Jon

If you think it might be RF interference, have you tried a different channel? (I'm assuming, without having time to actually look it up, that the 600ex-rt is capable of operating on more than one channel.)