04-25-2016 01:15 PM
" Of course that leaves open the question of why it sometimes happens and sometimes doesn't."
Of course. What randomly occuring event is making the difference? My guess is lighting. I would be very interested in knowing the exposure settings in the two sample pictures, as well as the camera and flash modes that were used.
05-06-2016 05:35 PM
I'm a little puzzled here. If you set everything to manual with fixed flash power, fixed Av, Tv and ISO and I assume your strobes can't do ETTL...wouldn't it get darker when you move further away from the flash source? Light loss is distance squared, right ?(double the distance, 4 times the flash power). If your flash can do ETTL, I guess it did not have enough power for the distance you had.