I'm looking for a hot shoe cable to get ttl metering with off-camera flash for my Minolta system. I see that the electrical contact on a Pentax ME Super is different from that on the Minolta X570 and x700 which is still different from my 3-year old digital. It looks like there are 2, 3, and 4 contacts respectively. I'm using a Minolta flash made for the x-series. Just how careful do I need to be choosing a cable to correctly pass all the information?