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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. 



@ZR wrote:


This forum is Canon USERS... it's not a Canon Help Desk with Canon staff answering questions... although occasionally someone from Canon does stop by and contribute.

As a pro shooter, aren't you a member of Canon Professional Services? Have you contacted them about the problems you're having? That would be your best bet to get some help.


Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories


What I'm wondering is why this seems to have suddenly started happening with so many people? My flashes never lost connection. Then all of a sudden they started to last Fall. 2 R6s, 2 600EXII-RTs, and an ST-E3-RT. All possible combinations (with and without the ST-E3-RT as Sender) were tested and the links were lost at random times. I sent all of these to be diagnosed at Canon, and no issues were found. It's simply baffling. 

Exactly, I've been an off-camera flash photographer for 25 years. I love Canon, but this issue is very frustrating. They don't know (CANON) why the cheapest third-party flash manufacturers like Yonguno are never losing the connection between flashes and cameras.

This EXACT issue just started happening to me around the same timeframe as you. Same setup: 3 R6s, 4 600EXII-RTs, and 2 ST-E3-RTs. What a disappointment. I'm assuming they did charge you to diagnose at Canon?


Oh my goodness I am so glad I found this thread! I have been a wedding photographer for TEN YEARS, and this just EXACT ISSUE started happening to me 2 months ago. 

I've tried combinations of:

- 2 brand new R6 bodies with fresh batteries

- 2 Canon transmitters ST-E3-RT (one brand new)

- a combination of 4 Canon 600 ex Rt II (one brand new)

- all fresh, fully charged Enloop batteries

- Tried different channels, different custom ID numbers, turning flashes on/off, etc.

Like all of you, this mainly happens in homes or venues - indoors. It's absolutely embarrassing to be messing with these in front of clients, and my gear isn't working. As a wedding photographer, I can't have untrustworthy gear. This is awful!!!!! 

Any solutions yet? CANON PLEASE HELP US!!!!!!!

Product Expert
Product Expert

Hi ZR and the other posters on this thread,

I'm sorry to see you're all having issues with your transmitters and flashes losing communication. Through Canon support we do not have information on non-Canon equipment, so we do not have information on the capabilities of the Younguno flashes mentioned in this thread.

Looking at the replies in this chain it looks like you've all tried the main things to check with connection issues. Things like replacing the batteries in case some of them have lost the ability to hold charge and checking different channels. Another thing to check is to try pairing a single flash with the transmitter one at a time to see if the same thing happens. Sometimes if one of the flashes is malfunctioning it can cause issues like this. If this is only happening with a specific flash we would recommend sending that flash in for repair.

Another thing is related to interferance. Normally changing the channel to the strongest listed one can help in cases like that, but even then sometimes interference can still cause the connection to drop. Typically when that is the cause it will happen in one location but not another. If the issue is only happening in specific locations it would be good to check the channel strength on each flash in the set-up. It could be there is more interferance on one channel for one of the flashes and not on another.

We do take feedback from emails and forum posts into consideration when considering product updates. I have already alerted them to this email, but if you want to contact them directly in the future they can be reached by going to our website HERE and selecting Feedback in the top left corner of the site. We do take customer suggestions and feedback into consideration when we are updating our products and processes.

Hello, Hazel, Believe me, I tried everything you mentioned before. Canon r3 with STE-10 brand new and with my EL-1 $1100 flash. The problem is the same.:( I played with submenus with channels etc., everything and no result. I have no time to deal with the service time of two or three weeks when you shoot 20 wedding events per month. I bought more Yonguno flashes for $135  and a trigger for $95, which are perfect with no link drops. I lost hours and days to figure out something; It's not okay with the canon flashes in slave mode. The EL-1 is almost a perfect flash-on camera, but it's a shame when I want to use it in an off-camera style in slave; the function time is maybe 10 minutes. I spent more than $3000 on Canon brand flashes and will sell them now because I can't trust them. By the way, I ordered from Amazon the Yonguno transmitter, and with STE-10, and STE-3, the Yonguno flashes function hours without any misfire or link drops. Hazel, Please let me know if you find something NEW that I have not tried yet, to resolve this issue. 

Any updates if you've had any luck with your Canon flashes? I'm debating whether to drop all the extra money on the Yonguno flashes to have as backup. Such a huge disappointment with Canon. They just told me to send all my flashes in to CPS, which would end up costing me hundreds just for them to even START the process. 😞

I did a test outside. Not sure what was around but assuming there was less RF interference, the setup worked with no issues. In fact it seemed to fire off faster with no delay. Given I have mesh wifi setup at  home,  I think this  is the source of my issues. 

Just curious on an update - how have the Yongnuo flashes been working for you over the various events you've worked since your last post with respect to connectivity? (Does it matter if you use it with Yongnuo transmitter vs Canon ST-E3-RT?) I thought I read somewhere that the YN flashes tend to overheat (compared to a  Canon flash) with a lot of event / extended use.  Have you had any issues with that? I took a quick look at the Yongnuo user manual.  It looks very similar to Canon (600EX-RT). Have you found any major differences / "gotcha's"  in functionality?  I've also been considering Radio Popper PX - anyone have any thoughts on those?

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