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Speedlite Transmitter


I have a ST-E2 transmitter. I am trying to use it with my Dynalite power packs. The transmitter will fire the power packs however I get a grossly underexposed image. It seems to me that the flash sync is off. I have tried to adjust my 5Dlll to work. I am noticing that as soon as I touch the shutter release to focus the ETTL light comes on on the ST.

I am shooting in manual mode. Shuuter speed I have slowed down to 1/30th to see if it made any difference.


Has anyone any idea to what the problem is?


Thanks in advance. 



Sounds like you are in ETTL mode. That fires two flashes, one to test the exposure and one to take the image. If the other flashes are optically triggered they can be fooled by the pre-flash.


Set the flash mode on the camera to manual.


And run out right now and buy Syl Arena's Speedliters Handbook.

Thank you for your response.

I have gone through my 5Dlll menus several times now and have not discovered the way to turn off ETTL on my camera. What am I missing?




You might have to turn it off on the flash. Set it to manual.

Thank you.

I am using an ST-E2 with Dynalite power packs. 


The ST-E2 does have a focus-assist beam.   If enabled then it project a red beam pattern that the camera's focusing system can use to lock focus in the dark.



If this happens when do a half-press of the shutter button (or any button that activates the focus system -- including back-button focus) then that's just the focus-assist beam -- nothing to do with the E-TTL communication to external flashses.


When you actually full-press the shutter in E-TTL mode, that's when it would order an E-TTL compatible flash to fire the pre-flash so it can meter and determine how much power to use for the shot.  This normally happens so quickly most people don't even realize the flash did a double-flash (a pre-flash followed by the flash for the shot.)


Check to make sure you haven't adjust the flash exposure compensation (FEC).



Tim Campbell
5D III, 5D IV, 60Da

Thank you TC.

I have not changed the FEC. It is set in the middle for normal exposure.The Dynalite packs will fire on slave however still getting an exposure equivalent to ambient.


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