40d PC Terminal

[du8die]

Hi,

Does the 40d PC Sync terminal send TTL information?

:dunno

I wouldn't think so, but I have no idea.

Thanks for any insight...
d8

[pyry]

Hi,

Does the 40d PC Sync terminal send TTL information?

:dunno

I wouldn't think so, but I have no idea.

Thanks for any insight...
d8

No it doesn't, it's just "Now!".

(actually, there isn't even any complicated signaling, it's just a short across the terminal to trigger)

[du8die]

OK.

Reason I ask is because I bought a Cactus trigger. The flash I have (Promaster 7500edf) won't trigger from the shoe. So, I did some research, and found an obscure reference that the flash won't trigger unless the signal it is getting is e-TTL. So, process of elimination... I have a Hot Shoe adapter that I plugged into the PC terminal of the camera, flash triggers. So, either it is sending TTL info, or the flash will fire without TTL, and something is wrong with my incredibely cheap Cactus triggers. I can get a 420ex to fire just fine, so for some reason, the Cactus triggers (which are working) are not working with this particular flash.

Frustrating.

Thanks,
d8

[ziggy53]

Unfortunately, modern cameras and flashes also use electronic switches for the flash trigger and those switches have a polarity as well as state (on/off). I have had some luck using a Wein SafeSync (http://tinyurl.com/2x7pzz) to adapt polarity and allow proper operation in some cases, but the real solution is to use a flash which is correct and/or polarity tolerant in the first case.

I have had great luck with the Sigma EF 5xx DG Super flashes in those cases as well as older Sunpak auto/manual flashes like the 383 Super flash and even good luck with the Vivitar 285HV flashes.