During wedding receptions, my Sunpak 383s fire very inconsistently. Every time I press the test button with the Cybersyncs, they fire every time. When I press the shutter button, they don't fire.

Any ideas why this is happening?

I shoot with a Canon 5DMII with Canon 580EX on-camera flash, with 2 cybersync receivers and 1 transmitter. I purchased the cord from Flash Zebra to connect the receivers to the Sunpaks.

Is there a Setting I can change to allow my trigger to fire Sunpaks consistently?

  • \$\begingroup\$ 383s? Now that's a blast from the past. (They're almost 30 years old; Sunpak's competitor for the Vivitar 283.) Are they not firing at all, or just not syncing? Have you tried the CST with a different body? With a PC cord? \$\endgroup\$
    – user2719
    Commented Oct 23, 2012 at 4:36
  • 6
    \$\begingroup\$ What's the shutter speed on the shots that flashes skip? Perhaps it's faster than max sync speed (1/200 on the 5D mkII), this would require High Speed Sync - which neither your triggers nor flashes support. \$\endgroup\$
    – Imre
    Commented Oct 23, 2012 at 17:56
  • \$\begingroup\$ 2 things come to mind: It sounds like either the camera isnt sending the signal to the transmitter or the transmitter isnt receiving a signal for some reason - check EVERYTHING including your in-camera settings. \$\endgroup\$ Commented Dec 21, 2012 at 10:28
  • \$\begingroup\$ I am having the same issue, it sounds like exactly. I have e-mailed cybersync. They told me they think it is the cord between the transmitter and body. They have already sent me one new one, but I am now having the same issue. Would love to know if you found a fix for this issue. Jessica \$\endgroup\$ Commented Mar 20, 2013 at 20:30

4 Answers 4


Pressing the TEST button on the Cybersync should always work if the transmitter and receiver are on the same channel, that is how it is designed.

Now the question is ... how is the Cybersync transmitter connected to your CAMERA, not your 580EX flash? I hope you do have a PC-SYNC cord connecting the camera body to the Cybersync transmitter. If you do, then the issue is probably a bad connection or cable.

  • 1
    \$\begingroup\$ PC stands for "poor connection." \$\endgroup\$
    – Stan
    Commented Sep 7, 2013 at 21:55
  • \$\begingroup\$ haha or for "poop crap" \$\endgroup\$
    – Julian
    Commented Jun 14, 2014 at 23:09

I’ve read this question several times and my answer at this point stands.

This sentence I shoot with a Canon 5DMII with Canon 580EX on-camera flash, with 2 cybersync receivers and 1 transmitter.

It sounds as if the original poster of this question is attempting to trigger the Cybersyncs from the transmitter in the Canon 580EX on camera flash.

The possibility of frequency incompatibility is paramount, even hard wiring with a PC sync cord will do nothing basically it’s off channel.

Part 2

It appears that the poster can trigger the flash units with the transmitter test button, making me believe that “if” the poster is using the transmitter on the camera hot shoe not the 580EX then the connection between them is faulty.

This whole issue can be caused by a weak transmitter battery To much distance between the transmitter and receivers Attempting to trigger the receivers from the on camera 580EX flash Radio interference from guest and camera crew’s own communicating devices. Units may only work within line of sight

One last thing is the trigger voltage from the 383’s is massive and if a 383 has been put on the Canon 5DMII it’s possible that the camera flash circuitry has been burned out.

Performing the test I outlined about will show where the problems is

Failing all this then contact “Buff” Help Center


The test button actually becomes the trigger no signal is required from another source.


I've read the post several times and my first impression is that the poster is attempting to trigger the Cybersyncs VIA the Canon 580EX flash.

I suspect you are mixing new flash units with old film flash technology they won't sync.

Here is my take of the subject, If you are going to use "old" flash technology which works just fine then everything from the camera needs to use the old system as well.

Canon uses an ETTL system that most manual flash units won't respond to, you would think that if the camera flash goes off then it'll trigger the slaves, not such the case.

Off camera cords that are compatible with your camera will have multiple connections at the base to communicate with the flash, however to use the older flash units they only require the center post and the mount becomes the ground.

Sorry this may get a little wordy but here goes. I use to fire my studio strobes with a PC cord from the camera, no PC socket you can purchase a hot shoe accessory with a PC socket. Once the studio strobes fire all the lights with slaves will fire AND at the correct time.


Check you camera and custom functions it may need to "be told" to not use E-TTL function, in other fire manually. It could also be linked to the Auto Focus assist beam function. If the flashes trigger from the transmitter test button then it's a good bet it the camera flash function(s)


Normally I set studio cameras at ISO 100 shutter speed at 1/60, I'm now using a sync speed of 1/125, new camera will sync at 1/200 and 1/250 which is slightly above "some" older flash units. It would be different yes if it was a leaf shutter lens but it's not.


Using these transmitters and receivers you no longer have E-TTL it's MANUAL and the use of a light meter is needed to properly set your aperture. If you want E-TTL then you need to buy the flash units capable of doing this triggered from the 580EX transmitter

Robert Taylor

  • \$\begingroup\$ The Cybersync units discussed in the question are Paul C Buff's radio triggers; E-TTL is not involved here. If you can modify your answer so that it only applies to remote radio triggering and its potential problems, that'd be lovely. (We're still waiting for the no-fire vs no-sync answer, which would clear things up immensely.) \$\endgroup\$
    – user2719
    Commented Apr 23, 2013 at 22:24
  • \$\begingroup\$ From the original post I saw nothing about radio triggers. \$\endgroup\$ Commented Apr 24, 2013 at 3:34
  • \$\begingroup\$ I know what the problem is I just can't get this forum to work properly for me. \$\endgroup\$ Commented Apr 24, 2013 at 3:43
  • \$\begingroup\$ Yes EttL is involved if the person is attempting to fire the units from the 580EX flash transmitter which won't work properly or sync if it does manage to trigger the receivers. Modify my answer to apply to remote radio triggers? Sounds as if they are working just not communicating with the camera. Apply only? There is no one specific problem or solution to this person problem I was covering several potential issues. \$\endgroup\$ Commented Apr 24, 2013 at 14:10
  • \$\begingroup\$ Read again—there's a 580EX in the hot shoe, but there are Paul C. Buff Cybersync units being used via the PC terminal as well. eTTL doesn't apply to the PC terminal which, like the centre contact of the hot shoe, is directly connected electrically to a switch triggered by the opening of the front shutter curtain, and is independent of the flash metering system. \$\endgroup\$
    – user2719
    Commented Apr 24, 2013 at 16:14

If this is not a system designed to transmit ETTL info to the radio receiver, then set the camera selector to "X". This will fire the transmitter. You will have to use manual settings like shutter 160 and f8 with ISO 100 or 200.


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