Why 600EX II RT / ST-E3-RT Drops Wireless Link

[JLCKJC]

I am posting this information in hopes it is easier to find. It was originally a reply to an earlier post but may not be easily discovered.

I believe I have proven the theory that the Canon ST-E3-RT (ver. 2) / 600EX II RT wireless system is dropping wireless links because of external electromagnetic interference. As I mentioned in an earlier post I ran a number of tests yesterday with the ST-E3-RT sender and three 600EX II RT flashes, trying different channels and ID's. This testing was done in my home office not far from my Wi-Fi router. This home office has a single router and the normal complement of connected wireless devices (a couple of TVs, an Echo Show, one Samsung and one Apple cell phone). In this environment I experienced drops in less than a minute to at most 12 minutes. Some channel/ID combinations were better than others.

This morning I conducted a similar test on the same units. This time, I created a Faraday cage of sorts by placing all units (sender and Flashes) in a metal filing cabinet in my garage. This was in hopes of shielding them from most of whatever electromagnetic interference I have in my home office.

They ran flawlessly for over an hour before the flashes powered down as they were set to do. I then cycled the power on the remote, the three flashes woke up and reconnected and flashed when the test button was pressed. It's been over 30 minutes since the system was powered back up and still no drops. Each flash is in its own group; A, B, and C. A & B are in ETTL mode, and C is in manual mode at 1/128 power.

I believe this series of tests and the experiences that many of you have shared on this forum proves that the Canon flash system is unreliable where low to moderate electromagnetic interference exists. The system appears to be unsuitable for most venues in which it would likely be used where Wi-Fi and cell phones are in the vicinity.

This is an old design, but it's still being sold by Canon. The ST-E3-RT (ver. 2) was introduced a year or so ago and the EL1 & EL5, which use the same wireless protocol and have been reported to also have the same issues, were also introduced a little over a year ago. 

Now the question is, how do we get this information and test results in front of Canon so something might be done about this issue. At the very least they should stop selling this system until the problem is resolved in current production units. It's simply an unreliable system for real-world applications.

PS: As I post this note, it's now been 1 hour and 55 minutes, with no dropped links.

PPS: The flashes went through another auto power off as programmed and were again powered up when the ST-E3-RT was power cycled. Their wireless links restored as expected. I concluded the test after 3-1/2 hours with no dropped wireless links. I then removed the units from the Faraday cage (metal filing cabinet) and returned them to my office where they all lost their links in less than 5 minutes. Again, this points to external interference as the cause in a fairly common home Wi-Fi environment. This system appears not suited for its intended wireless use.

[pmsakamoto]

That was a good video. Kaitlyn does not diagnose the issue but has the common sense approach of just saying her obervation that the Godox link does not fail and the Canon one does fail in similar situations. Godox does what she needs it to do - help make money - and the Canon extra features and high price do not. Yeah!

[LeMolinet]

Very useful information here, thank you all for posting. I too experienced this issue over the last 2 years. Sadly, for me, I think it's time to move on. I was just on the phone with the Adorama people and they mentioned they were aware of the situation but did not have a solution for it. I'm looking to purchase a Flashpoint monolight as we speak, of course I'd have to purchase a compatible trigger for it as well but Black Friday sales help a lot. I was told that these units as well as other aftermarket flash units don't have this issue at all, any thoughts anyone? Could this be true? Have any of you moved away from the Canon Speedlite RT system yet? 

I'm not getting rid of my Speedlite RT kit just yet because I already invested too much money and because I find it useful in some situations.

I will be testing my new Flashpoint set up here soon so stay tuned. 

[JLCKJC]

I got three Godox receivers for of my three 600ex flashes and use the Godox controller on my R5. Works reliably so I was able to preserve my investment in the RT system until I switch away from Canon altogether.

[pmsakamoto]

I did exactly the same thing for my three 600ex speedlites and put the Godox controller on my R6mkII. Great results. I've posted elsewhere on this site that I ran tests with the Westcott system flashes and controller and also had good results. I tested the very newest (at the time) Canon EL5 and ST10 controller. No joy - fails just like the older stuff. 

[LeMolinet]

Very interesting 🤔, thanks for all the info.

[awlens]

I'll mirror what others have posted about how when you isolate the signals everything works, and how switching to Godox is a solution. I had a very complex studio setup involving 12 600EX RT (mark 1) flashes and a ST-E3-RT (ver 1) transmitter. Whereas it worked well in prior shoots in my townhouse, the proliferation of Wi-Fi among several close homes likely became too much and I no longer could get anything to fire. After researching online, I took a couple of flashes and the transmitter to a large park and they worked great. I took some advice I found in a forum and got a Godox transmitter and a flash receiver. That worked perfectly in my townhouse where the Canon system had failed. I was even able to adapt non-RT Canon flashes to work remotely this way. In fact, the Godox transmitter can control features of Canon flashes (using the Godox receiver/adapter) that Canon's own controller can't (i.e. setting zoom, even down to group level). I was quickly hooked and began collecting more and more powerful Godox lights (from AD200pro to AD1200pro over a few years) and so I'm really glad Canon lighting failed me. The quality of my portraits has improved so incredibly much. I still integrate my Canon flashes into some studio scenes (usually to light the background) but I've found Godox equipment to be so versatile on location and way more cost-effective. With the power of *Godox strobes (the likes of which Canon simply does not offer) I have been able to overpower the sun and turn the outdoors into a studio. I still love Canon cameras and lenses but fortunately I opened my eyes to alternative lighting solutions and I'm far better off for it. *NOTE: Sometimes you can get a better deal on Godox lights when purchasing under the Flashpoint branding (often as a bundle with related items).

Alan Wheat

awlens dot com

@alanwheatphotography

Yes, I know that might read like an ad, and this is my first post here, but it has some useful info and is supported by other messages in this thread.

Edited to correct a misspelled word

[pmsakamoto]

You are 100% right-on! In a way, I sort of wish I'd just pivoted entirely on the flash issue and gone to Westcott (better US support), but as you note, Godox makes greatt gear at a great price! My controller and receivers have been a life saver. So has the B&H return policy which allowed me to evaluate the EL-5 and ST10 to see if Canon had improved at all (they have not) without committing more than shipping. 

Not clear what Canon is focusing on, but it sure is not wireless interference with their flash system.