REALLY ignorant question

[crayonblue]

Ok, we have the Canon 20D and just purchased a 24-70L. Now, we need an external flash. I know very little about photography (my husband is buying all the equipment) and I want to make sure I can use the basic modes (portrait, landscape, etc.) on our camera with the external flash (whatever we buy). I don't want him to make me learn how to use this camera too quickly! :)

Just to make sure: we won't be able to use the built-in flash with the 24-70. Correct?

[snibbetsj]

Actually you can use the built in flash with the 24-70 but the size of the lens partially blocks the flash giving you shadows. If you can get the Canon 580EX, if that's too expensive, go for the 550EX (next in line)or the 420 EX.

[wayne53]

Are there really any advantages that should make you spring for the 580EX/550EX instead of the 420EX?

[crayonblue]

Does an external flash over-ride the built-in flash? Will I be able to still use my trusty portrait setting? (since I don't know what I am doing!) Will it automatically flash if I need a flash?

[rent]

if you have an external flash in the hot shoe, the built-in flash will not work. any of the EX series canon flash will work with your camera. choosing one is a matter of considering the power you need, featureset and $$ you want to spend. 420EX is most economical and good for starters.

-alex

[scottbergerphoto]

Are there really any advantages that should make you spring for the 580EX/550EX instead of the 420EX?
The 420EX is:
1. Weaker. GN of 42 instead of 55 or 58 meters.
(The distance a flash will carry = GN/ f stop
2. No Manual Controls.
3. Cannot work as a wireless master.