Archive for sync

Issues with Canon Flashes and RF Noise, Pt. I

Posted in Unsorted posts with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on August 23, 2009 by restaurantouring

Once again, I apologize for the lack of updates. I’ve been busy lately — I suddenly found that I needed to find a new roommate or be financially forced to move out, I was unable to find a new roommate that I could trust, and subsequently had to move out. Additionally, work has been crazy and I have been absolutely engrossed with photography as of late. Mostly, I blame David Hobby and his Strobist blog. If you’re a photographer and you’d like to learn more about how to use flash in an elegant and intelligent manner, Strobist is THE place to go.


Long story short: I (and many other people) have problems getting my Canon-brand strobes to sync off-camera while using Pocket Wizards (the industry gold standard for rock-solid reliability and range — even through walls and other objects). While PW advertises ranges of 1800 feet with the old Plus II’s and maybe half of that range with the new PW TT1 and TT5’s, I can’t seem to use them at distances greater than 35 feet, max. What’s going on? Read on for the full deets:


Despite saying that I’ve been engrossed in photography lately, I haven’t actually been shooting as much as I would have liked. I spent most of the weekend agonizing and researching radio frequency interference (RFI or EMI for electromagnetic interference) generated by my Canon flash units. As it turns out, I happen to own two of the [RF] noisiest flash units ever produced by Canon (430EX and 580EX II), and I’m fortunate enough (sarcasm) to own what appear to be two PARTICULARLY noisy specimens of those models.

If it sounds nerdy, it is. It’s got nerd in spades written all over it.

Warning: nerdy pseudo-scientific rant mode ON. I apologize in advance to anyone actually reading this and especially to anyone who finishes reading this post. Also, be aware that this situation is a bit complicated. There are a lot of details and factors involved, and I may not get to every single little issue here in this preliminary post. If I did, you’d all be reading for hours, probably (That was sarcasm. Sort of).

RF noise can be a big issue for me (and other people who use radio triggers) because I shoot my flashes off-camera. The industry’s gold standard for firing flash units off-camera are little radio triggers called Pocket Wizards (PW). You simply hook up your flash to a PW receiver, stick a PW transmitter onto the hot shoe on top of your camera, turn them on, and fire away. The PW’s will synchronize the firing of the flash to the opening and closing of your shutter, up to the maximum “sync speed” of your camera (most Canon cameras will go up to 1/125 sec to 1/250th of a second, even though they’re advertised as 1/200 minimum. Personally testing my cameras tell me 1/125 is the fastest I can go on my old XTi. Not that that matters to you — unless you own an XTi and you’re looking to sync off-camera).

At any rate, PW’s are supposed to be super super reliable, with an advertised range of 1600-1800 feet. That’s almost 1/3 of a fraking mile. That’s insanity.

On top of that, since it’s RF, you can run around, you can trigger your flashes even with walls and large objects in the way, you don’t have to worry about staying close to the flash units, you don’t have to worry about line-of-sight from your transmitting “master” unit to your receiving “slave” units. . . . It’s just a really AWESOME idea.

So what’s the problem? I can’t seem to reliably trigger my strobes from more than 10-15 feet away when I’m outdoors. As you’ve no doubt gathered by now, it seems like the RF noise from the Canon flashes I own (again, the 430EX and the 580EX II) is causing interference with the PW tranceivers I have (“Pocket Wizard Plus II”‘s — which cost me about $160 – $180 USD each when I bought them. I have two and you need at least two to use them).

Research online (e.g. Rob Galbraith’s tests) confirms this: it turns out the frequency of the noise generated by the Canon strobes is at about the same frequency of the channels that the PW’s operate on. Oops?

So who’s to blame?

Canon, for making such noisy strobes? Nikon’s strobes emit almost no noise at all. Nikon’s strobes are also a lot more powerful and useful than Canon’s strobes, yet they’re similar in price. Most third party strobes emit almost no noise, too. Why is Canon so noisy?

Or is PocketWizard to blame? They’re bent on backwards compatibility so it’s not like they want to change the frequency on which their units operate. They picked the frequency to use because it was one of the least noisy frequencies available, after taking into account RFI generated by any and all electronic equipment in the US (basically, anything powered by electricity tends to produce some sort of EMI at varying levels. There are laws that are supposed to regulate EMI noise, but it’s hard to figure out what’s being noisy and what’s not sometimes). Funny how Canon’s flashes are so perfectly noisy, isn’t it?

Or maybe I’m the one to blame? After all, I probably should have done some more research before spending the big bucks to buy all this gear (all in all, the two flashes, the PW’s, and the necessary adapter cable required to use them all cost me $1000+). Maybe I should have waited to hear more in-depth, intelligent reviews instead of leaving it up to the sometimes clueless customer/user reviews on Heck, my original intention was to go with Nikon when I first wanted to get my feet wet with the whole DSLR scene, but I went with an XTi cuz it would have saved me 200-300 bucks (which is a lot when you’re a poor, starving, buried-in-debt-as-it-is college student trying to foolishly get into DSLR photography).

:sigh sigh:

I just want my shiny, expensive toys to WORK, damnit!

But in case you’re wondering, there are ways around PW’s inability to reliably trigger remote Canon flashes. The folks at PW recommend a $6 ferrite choke from Radio Shack. I’ve ordered one and will test it. I’ll let you know about the results, even if it may be redundant considering the info you’ll probably find on the web if you just look hard enough. I don’t care. I want to see it with my own eyes.

PW is also developing an RF shield that is worth mentioning, except it will likely cost $50 or so when it comes out (IF it ever comes out, since it’s taken quite a long time for them to develop a simple RF shield).

Additionally, there’s a relative newcomer to the off-camera RF triggering scene. They’re called RadioPoppers and they seem to be really awesome. They’re not perfect and I’ve got some issues with those units, too (I don’t own any. Yet. I just decided to do some heavy research first to prevent getting bitten by more expensive radio triggers again), but if you’re looking for rock solid stability and reliability up to 600-800 feet and you need that capability RIGHT NOW, it’s a good alternative to PW’s until PW and/or Canon fixes their shizz. Still, I can’t give them a full, 100% recommendation, and I’m not trying to endorse Radio Poppers here.

As the name implies, RadioPoppers DO operate on radio frequencies, but at a higher frequency than the noise emitted by Canon. Field tests and controlled tests confirm that RP reliability is pretty darn good. REALLY good, in fact.

What I love about Radio Popper is that they offered a limited time rebate deal for their first generation triggers. Basically, if you had a 1st-gen trigger, you could send it back for a heavy discount off of their 2nd-gen product. If PW’s weren’t so ubiquitous with serious enthusiasts and professionals who shoot Canon, I would suggest/pray/hope that PW did this, too. Recall the old units, either retool them to operate on a frequency that doesn’t get affected by the RF noise emitted by Canon strobes, or offer a discount for people looking to upgrade to their new, vastly improved, E-TTL-compatible triggers (Flex TT5 and MiniTT1).

And forget about complaining to Canon. Word on the net is that they don’t listen, don’t seem to care. Whether or not this is true remains to be seen by me, personally. I’ve got big big big issues with Canon’s flash units even besides the RF noise issue, since it only really came to my attention recently. Circumstantial evidence leads me to have problems with their apparent drive to excel and innovate as well, but I won’t get into that since I’ve already written a fraking 12-page essay to you about it with this post. Plus, I’d like to give ’em a little more time before actually blowing a gasket.

/end nerd rant

Again, I apologize for the long rant. If you have any thoughts, comments, questions, disagreements, whatever — PLEASE sound off in the comments. I do moderate comments, so if you wish to remain private please start your comments with the words, “DO NOT PUBLISH.”

I’m just trying to put more info out there on the net to let potential customers of these companies know what’s up before spending the obscene amounts of money needed to use this stuff — trying to help out. If a meaningful dialogue can be started here, it will be worth it — even if I only ultimately help out ONE dSLR user out there.


Coming soon:
– field tests with range issues on the above mentioned flash units.
– putting the ferrite choke through its paces
– testing some work-arounds to increase range
– DIY RF noise shielding (a.k.a. where’d I put my aluminum foil?)
– more nerdy Canon rants