Showing results for 
Show  only  | Search instead for 
Did you mean: 

Problems using external flash 750d/T6i


Hi, i'm trying to use a wireless transmitter and reciever on my 750d to flash. When i use my external flash on camera i have no problem, i can get into the menu and all works just fine. But with this transmitter on the camera i cant get it to work and get the message in external flash settings 'this menu cannot be displayed. Incompatable flash or flash's power turned off' I just want to get a simple signal to this transmitter to flash, dont need all the ttl functionality. Does someone have a solution?



What model external flash?

What model transmitter?


I just use a 430 EX II with the built-in flash as an optical wireless transmitter and everything is fine.

The problem is not  the optical, i tried it and it works for me also. But the problem im having is with a PT-04 TM system. Using radio waves, a transmitter unit on the camera and a receiver hooked to the flash. The flash im using at the moment is a Viltrox JY-610c.


If i turn on the transmitter and the receiver and hook up the flash to it i can make it flash using the test button on the transmitter. Its just getting the 750d to fire a signal for it.

Make sure you are not using Liveview. Flash firing will be disabled when using Liveview with third party non-ETTL tiggers or flash units. 



Mike Sowsun

Im not using the liveview mode but thanks for the tip. Is there a way to force a flash trigger other than using the build-in flash? Lets say in daylight conditions i still want to use the flash, i can do this with the build-in flash using the button on the front to flip it up. Is there a a simulair way to do this with an external flash?

With the flash menu.

Hahaha, but i cant get in the flash menu when i have this transmitter on the camera!Smiley Very Happy


It's obvious to me the camera doesn't recognize your flash transmitter as a legitimate flash device.  If this thing is supposed to be compatible with Canon cameras then it must have had an old firmware.  Your best bet is to update the firmware and hope for the best.


After market transmitters like Godox and Yongnuo work so much better than what you are using now, though.  I would not skim on important equipment such as this.  I was surprised to see this PT-04 system only costs $8 on get what you pay for...

Diverhank's photos on Flickr

Is this a canon thing? I used to shoot on a sony dslr. I had the same ebay PT-04 set for that one, never any issues. I can understand having communication between the camera and the flash is easy.. but necessary? Its just a spark, whats so hard about that! I dont like it telling me i dont have the flash it wants me to to use.

I found a work around that kind of works. I turn on the camera and flip open the build-in flash and than push it down a little so i can slide the transmitter into the hotshoe. Sliding the transmitter the wrong way round works the best. Then when i close the build-in flash i can flash via my transmitter to my receiver. It only works doing it this way and the shuttertime is very long because it is not synced, i will have to do that manualy. It's not the best solution all together. Probably best to look into a ttl radio flash trigger in the future, a lot less hassle.

I miss the low tech good old days Smiley Happy