Sorry for the newbie Q's, but what exactly is E-TTL, and how is it different from Manual?
I have been using the flash on my camera recently, in just a "plug and play" sense, I assume that this is E-TTL? I have been changing the power of the flash, but that's about it.
Thanks.
E-TTL is Canon's auto-exposure flash system, and it sounds like that's what you've been using. You can adjust the flash power with +/- compensation, or switch the gun to manual and control the power that way.
If you want E-TTL, the cheapest way is with a dedicated extension cord - up to 10m. Either that, or for cordless you need a master controller on the camera. Yongnuo have an interesting new ST-E2 clone just out that looks very promising but is largely untried at the moment for £100, and uses the same near-IR light signals as the Canon system. If you want the additional advantages of radio E-TTL, then that's £400 upwards.
E-TTL is great when you need to set up and shoot fast, or when the flash to subject distance is changing quickly, ie tracking kids for example, plus you retain remote high speed sync which is really useful outside.
But if you are taking the trouble to set up a portrait session and have a little time, then manual is fine. Many people prefer it, because it locks everything and you always know here you are.
Honestly, I would just get the RF-602. It will certainly do the job and may be all you ever need. Also an absolute bargain
PS For portraits, I would also get a simple shoot-through brolly and pop it on a stand with an adapter - £30 the lot. You can do a heck of a lot with that, and build on it any which way you like.