I'm using the SU-4 with two speedlights...SB25 and the SB28. Either one can be used as a master or slave according to the manual. My question is on TTL, does the master speedlight tell the slave flash the correct ISO or does that have to be set manually? Also on TTL I think the ratio of lighting is 1/1 unless you adjust the slave flash to be a stop hotter or less depending on what ratio of lighting you prefer.
Thanks for any information you might have regarding this equipment.