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Radio communication issues.EL-1, 600EXII-RT, 430EXIII-RT, YN686EX-RT, ST-E3-RT Speedlite Transmitter


Hello, Canon. Hi everyone, I've been a professional wedding and event photographer for 25 years, and in the last two years. I have used around six off-camera flash techniques using the six flashes mentioned above. After hundreds of weddings in the previous month, I have connection-linking issues. I read and checked every tutorial possible, and nothing helped.:( I know the menu's sub menus' custom settings, and the only flash linked for hours is the Yonguno YN686EX-RT. All of my Canon brands flash, losing connection after 5-minute. I attached two cellphone photos where you can see the problems after 5-minute. CANON or some of you guys have any idea what's going on? PLEASE HELP ME! Thank you so much. 



I am having exact same problem. 

el-1s won’t hold connections between each other. 
Nor will they maintain a connection with ST-E10. Nor with a ST-E3-RT (version 2). 

What on EARTH is going on? RT wireless connection is basic required functionality. And these are flagship flashes!!

Not having any problems with my Godox flashes.

Help! If Canon doesn’t fix or assess this rapidly no one (who needs this) will buy Canon flashes again … and they’ll have a lot of refunding to do. 


Same issue here. I have 5 600 EX-RT’s and 2 ST-E3 RT’s.
Three weeks ago here at our home in the Philadelphia suburbs, this situation started, never ever before since 2012 when I invested into the 600 system. 
I tried rotating transmitters, 600 as Master linked to other 600 slaves. Changed batteries from Eneloop, to Alkaline to Powerex LD NiMH. Changed channels, ID. 
Tried and failed on both of my 5D Mark III’s. Everything would link Green light, and then unlink Red light on all of the 600’s in 5 minutes or so. However the Transmitter Link Green light would be on.

Last weekend we traveled to our other home in Central Pennsylvania. I linked everything in the Garage where I have Paper Rolls anchored to the wall, “my studio” everything worked just fine, like the old days. Linked all 5 lights with one transmitter for an hour, no drop. Did the same with other camera and Transmitter and again, just like the old days with seamless transmission. 
Back home to house in Phila. Suburbs…. Failure with in 5 minutes.  
next gig………. Good Luck. 
I did send my 2 Transmitters and four flashes in for service for update in Firmware to both 600’s and Transmitters. 
While they updated firmware in Transmitters, they did not in all four 600’s. They said it was up to date. However transmitters are now “Sender” not Master. 600’s are still Master and Slave…… not Sender and Receiver. Hmmmmmmmm…….

Could that be the solution?……. Don’t know if completion of service request is not fulfilled. 
No Apple HomePod here. Do have a Bose Soundlink Revolve II I recently purchased right before situation in another room and floor. This is powered off all day unless listening to when developing in Lightroom, as is my iMac, not while shooting downstairs and extensive Troubleshooting here as well. Took to neighbors house to doors away on back deck and drop again in 5 minutes.  
The next gig?????


This is quite the problem for Canon at this point. I have two of the brand new EL-1 flashes, and one of the older 600EX-RT flashes, and they all have a problem staying connected. Upon further investigation, it's not the ST-E3-RT with the problem because I turned off this transmitter, and turned it back on several times to see if the LEDs were still green, and within about 10 minutes, one of the EL-1s dropped the connection, so how can this be the transmitter problem? Based on my tests, it's the flashes that are dropping the connection, and we all know it's RF interference, could it be the new WiFi-6 wireless access points around the house and commercial venues? There are other posts that suggest Apple HomePods are the issue, but these items are not in my house, so I cannot confirm or deny these are the conflicting hardware. I do have the new WiFi-6 access points from UniFi as my "MESH" Wi-Fi system in the house.

I made some other tests by purchasing the "sock" that covers the flash and sort of shields it from the RF interference, but this causes more grief because you are essentially now limiting the ability for the transmitters to communicate to the flashes. These are not the solution either, as the link was still dropping. Ugg...
So I did some other tests, and I bought the ($80 USD) Godox transmitter X-Pro II C, and purchased two of the ($40 USD) Godox X1RC receivers for mounting to the Canon EL-1 flashes. Using this configuration, I NEVER lost the link from the Godox transmitter to the Godox receivers, EVER. I let this run for hours, made several tests, used my Canon R5 in different configurations, manual mode, ETTL, and the connection stayed solid, I never lost the link to the flashes.
That being said, there are plenty of posts throughout the Canon forums where this is a huge problem for Canon, and you hear suggestions from Canon support: "Try changing the batteries". Are you kidding me, that is ridiculous, they have nothing else to suggest because deep down they know that interference with all of the "Internet of Things" on WiFi-6, and the 2.4 GHZ band is full of traffic. So why does the Godox (Chinese made) hardware stay connected?
Unfortunately, this means a few more dollars for additional hardware, more AA batteries, but at least the connection is NEVER dropped, and I do not have to power cycle the Canon flash and Canon transmitter. The other downside to Godox transmitters & receivers, you don't get all of the features that Canon has to offer, but in reality, do you really need to have the flash at less than 1/128 power? I say this because the Canon transmitter and EL-1 flash can be set to 1/8192 power, and the Godox can only be set to as low as 1/128 power, which is not a big deal in my opinion. You do however get some pretty cool features in the Godox transmitter, you can turn off any single flash by double tapping one of the 5 group buttons, a useful feature that is super fast.
Deep down, I really think Canon has a problem that may not even be fixable though firmware, it's most likely the frequency that Canon uses that is conflicting with nearby RF devices. In my opinion, why Canon does not reconnect automatically instead of power cycling the hardware is beyond me.


I’ve read all the comments so far and i have pretty much the exact same problem so I won’t elaborate/repeat what was already said. It is pretty sad that such a major company like Canon can’t fix, let alone properly address this dropped link problem. It is as if they want users to try cheaper, yet functional alternate brands. I currently use Cybersync transmitters and receivers with relatively few problems, but wanted to “upgrade” to a Canon transmitter figuring it has to be better. The menu learning curve is a bit high, since I’ve never used such a sophisticated transmitter, but with enough effort reading the instruction manual I thought I could figure it out. I was constantly second guessing myself, because the connection randomly dropped no matter what combination of setting I used. After reading the comments, I felt relieved I wasn’t an idiot, but I was also pretty pissed that I wasted my time and money on the ST-E3-RT.

I still believe this is a problem of the Speedlights (EL-1 or the 600EX series), and I do not believe the ST-E3-RT is the issue. The reason I say this is because I connected two (2) of the EL-1 Speedlights and one (1) 600EX speedlight to my trigger (ST-E3-RT version 2). And do I feel stupid, my version 1 unit had the same problem, so now Canon got me 2X. 

I was making some tests by turning off the ST-E3-RT version 2 power switch, and when you do this, the green link obviously is off on all 3 speedlights because the ST-E3-RT version 2 is off. Doing this several times, just to see if the speedlights continue to make a connection. 

Now to isolation: I turned off the ST-E3-RT version 2 for 15 minutes, and then turned it back on, and one of the EL-1 speedlights had NO link, but the other two speedlights had a link. So, this leads me to believe it's NOT the ST-E3-RT version 2 because it was OFF when the EL-1 speedlight lost a link, AND the other two speedlights still had a link. I gave it a few more minutes, and my other speedlights EL-1 and 600EX had lost connection. 

Like I said before, Canon does not care, they have made the sale, they have the money!

Eventually Canon will drop out of the Speedlight arena because Godox and other third party vendors are kicking them in the sales arena. 

I've heard Sony has dropped out of the speedlight arena due to the market of third party flashes are reliable and 1/3 the cost of the big name brands. 


Seems like only fair that Canon refunds everyone.I would be also ok to return all my canon triggers and flashes and get credit for other canon purchases. 

Agreed! I even bought all new transmitters and flashes last year, thinking they were just getting "older" and dropping links due to age. So now Canon got even MORE money out of me - and then I had to buy Godox flashes since they're more reliable right now than my BRAND NEW canon ones. So sad!


Same exact issues here too. It has screwed me up big time at weddings. Both Canon EL-1 and 600ex flashes dropping connection like crazy. The wireless system is not even useable anymore on Canon’s flashes.

Buy the Godox transmitter and receiver so that you can still use the Canon speed lights.


I had the same problem with the radio transmission system not working. All on same Channel/ID, using fresh Eneloop batteries. Issue persisted using ST3 as master or using Canon 600 EXRT as master. Multiple calls to Canon "support" were useless. Finally saw a You Tube video by Katelyn James recounting the same Canon failures. She switched from Canon to Godox (sold as Flashpoint by Adorama) and the problem was resolved. So, I made the switch and now everything works perfectly. I have no idea (yet) about long term reliabilty but so far... it works!

Sold my Canon flashes and doubt that I will ever go back to Canon.