# 600ex-rt and the dead zone



## jaayres20 (Dec 30, 2012)

I am a wedding photographer and I have shot 26 weddings this year with three 600ex-rt flashes and for the most part am very happy with them. However, there have been two occasions where there has been an area about 20-30 feet in diamater that the master goes all screwball and the link goes in and out. I was shooting a wedding last night and my assistant also had three flashes and hers did the same thing in the same "dead zone" We were both on different channels so we were not interfering with each other. I did everything I could think of like change batteries turn them on and off and I even did a channel scan to see which one had them most strength. Still there was that zone where the flash had issues and the link would go in and out. It was in the middle of a large room with nothing that I could see that would cause issues. It wasn't next to anything else electrical that I could see. The only thing was a florescent fixture about 30 feet in the air. Once I was out of the dead zone everything was fine. Unfortunately it was the dance floor so it made shooting the reception harder. I even tried to stand over by the DJ were I figure there would be the most interference and I had no issues. The dead zone was in the middle of nothing. Anyone have any insight?


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## FunPhotons (Dec 31, 2012)

Without a signal analyzer with proper demod capabilities there's no way to tell for sure, but my guess is that you've got a room full of people with cell phones in a building with some wireless LANs, all more or less working in the 2.4 GHz band. I've been to conferences with thousands of tech geeks, and while they provide 'high powered' wireless lan (Google conference) it was completely swamped by all the devices. 

As it turns out you have a little channel analyzer in that flash, use it to see which channels (if any) are cleaner. I haven't looked at it since I got it, but I think they show which channels are _empty_ (clean/clear), not which have the most 'strength'. 

The other option is to be prepared to fall back to optical if it happens again. 



jaayres20 said:


> I am a wedding photographer and I have shot 26 weddings this year with three 600ex-rt flashes and for the most part am very happy with them. However, there have been two occasions where there has been an area about 20-30 feet in diamater that the master goes all screwball and the link goes in and out. I was shooting a wedding last night and my assistant also had three flashes and hers did the same thing in the same "dead zone" We were both on different channels so we were not interfering with each other. I did everything I could think of like change batteries turn them on and off and I even did a channel scan to see which one had them most strength.


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## brad goda (Feb 11, 2013)

AH YES the "dead zone"

ive had this happen in interior situations and outside in totally open area...
I know its not a distance thing but some kind of interference be it phone wifi whateva....
ive done a few things that helped...
1. go to the closest 600 and turn off and turn on same with transmitter.. it relinked and held while walking away back to area where it started.
2. placed transmitter on off camera cable and held it on mini magic arm on tripod.
3. just moved the effected lights just a bit ... dont know why it worked but some standing radio wave voodoo... like sound radio can get jumbled in areas / close proximity to #@?* things...

I wish Canon made like a booster add on antenna or something like that to reduce this kind of problem and maybe give the system added working distance.


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