Canon off camera 2nd curtain flash fires both curtains!?

Update .. my camera is still unable to be changed from ETTL to Manual but I can switch the flash to manual and set the 2nd curtain flash output. It still has the 1st flash but with the flash in manual mode I can control the 2nd flash output. I have read mixed reviews on whether that first flash will affect the exposure or not. Curious to hear some more opinions .. I will try to test it out this weekend.

thanks everyone for the help! Even tho this first flash is still bugging me.

jamesbuddyrogers wrote in post #18067814
Update .. my camera is still unable to be changed from ETTL to Manual but I can switch the flash to manual and set the 2nd curtain flash output. It still has the 1st flash but with the flash in manual mode I can control the 2nd flash output. I have read mixed reviews on whether that first flash will affect the exposure or not. Curious to hear some more opinions .. I will try to test it out this weekend.

thanks everyone for the help! Even tho this first flash is still bugging me.

Hi, With SCS, what you are recording as the first flash will not impact your exposure at all. (With Canikon optical 'wireless' controlling flashes can be divided into Pre-flashes, which occur while the mirror is still down, and Trigger-flashes (one per shot), which are co-synchronous with the Capture-flash. Trigger-flashes can (just) show up unintentionally in FCS shots, but what you are perceiving as 'the first flash' in your SCS scenario, will not get captured.)

That's good to know. Thanks for sharing your expertise!