Well, I certainly didn't intend to step on anyone's toes.
If someone here asked me how fast my computer is and I told him that the CPU is an Intel 3930 Six Core Unlocked running at 3.6 Ghz with a 12Mb L2 Cache, I doubt if many here would know what I was talking about.
I would just say-very fast.
I believe what Tom wants to know is how his model digital camera will work in a certain setting.
So if i was the first to be asked, I would have sent him HERE for a simple explanation.
I commented about third party external flashes because some of them don't sync with certain model cameras in TTL mode.
I would have also strongly suggested that he ask around (maybe at a local photo group) where the best camera store is in his area.
If Tom can get an experienced person (and I found out they don't have to ancient like me) at a local store he/she can match his camera to the best external flash for that model and his shooting preferences.
My 2 cents