ST-2E fire 420EX and 550EX together?

[zenscape]

I have an existing 420EX and someone is offering to sell me a used 550EX. Will both of them fire together with a ST-2E?

Also, will they fire out in the same intensity? Thats to say, will the picture appear to be one side being more exposed than the other side if they are place on side by side (left & right) on top of the tank.

I am wondering if the above is negative, I would be better off to have a pair of 420EX.

Thanks and hope to hear your advice.

[hwchoy]

you definitely rather have a 550EX. as long as the flash output from the 420EX is not the limiting factor, then there should be minimal problem with imbalance. you can also use the ratio function.

[zenscape]

Thanks for the prompt reply. I will get the 550EX