Two 550EX or 550EX+580EX

I have an opportunity to buy another 550EX for a very competitive price (less than what I paid for the first used). I was wondering if it would be a good investment to learn/develop and shoot in a master slave set up or should I just be patient and buy a used 580EX (for about $300) when the 580EX II hits the market.

I am pretty happy with my 550EX on my 20D, I am ok with the cycle time (missed a few shots but I aint whining about it) and it works pretty well. I have held a 580EX with battery and it really does not seem that much lighter than my 550EX with battery either. I dont even have a problem with the controls or the two button swiel.

The primary reason for posting this question is coz I have read somewhere 580EX does some sort of temp correction etc. And would that alone justify wanting it in the setup I am aiming for.

The 580 is lighter, and recycles faster.. amung some other advances.

Nothing wrong with the 550ex, but once you get a 580, the 550 will never go on your camera again, you will only use it for a slave.

580EX if price is no object, but the 2 X 550EX's would still be a pretty good combo.
Depends what you want do do with them I suppose.

So is ETTL-II worth the $100-120 premium for a used 580EX. I understand that with the 20D the 580EX is supposed to work better under ETTL-II. Frankly a loaded 550EX does not differ that significantly from the 580EX especially when you are running with a BG-E2.

Given that there are no decently priced 580s in the market and I am getting a pretty good deal on a 550EX should I take it or should I just wait and get a 580EX to compliment my existing 550EX in a master slave set up.

I am thinking of getting into indoor portraits. I was blown away with the results of the 550EX on the 20D and so I ve been thinking about getting another flash to learn more about master-slave set up and off camera lighting. I am pretty sure my wife will kick me out if she sees one of those umbrella and barn door set up but having a second flash is not that offensive or obtrusive.

If your getting a deal on the 550, I would get it. Use it in your setup and downthe road when 2 lights arent enough get the 580 used or get a new 580EX II. I love the 580, but expanding your setup for less money with pretty good quality sounds pretty good. They could always be used as slaves later.

Cool thanks a bunch. I think I will be getting the second flash today or tomorrow. After that I think I need to read up on the technique too.

Edit: I just found out that the plastic stand that comes with the canon flash has a 1/4-20 thread which means I can mount the stand on my Slik Sprint Pro Tripod. This is pretty neat.

Yup, and if you get the Canon Dedicated TTL Cord 2, it has a tripod thread on the flash end. Just modify the cord to the length you need and you will have your master off camera too.

I use a 550EX and 420EX in multi-flash setups. I may get another flash, a 580EX, but if I could get a real deal on a good used 550EX, I would have no problem getting it.

I got the flash for about $200. And I tested it out briefly in the master-slave setup and it works great. I checked out Strobist blog and it seems pretty interesting. The big plus for using a RF/PC wired transmitter rather than an IR is that you can get out of the whole LOS limitations.

I have both. User interface on the 580 is much better. I agree with CDS here...
Both support ETTL-2 by the way. The difference ETTL - ETTL2 is made in the camera body.