How to use external Flash?

[demonsmercy]

I recently get an external Flash for my 400D. But I really have no idea how to use the flash. Sometime I got overexpose; in other time I got underexpose; and most time I got correct expose. I still don't know how to control the light from an external Flash. Do you have any tips? thank you.

[Saralonde]

Are you facing the flash directly at your subject? Sometimes it works better to bounce the flash off the ceiling or nearby wall. An entire book could be written on using an external flash, so I'll direct you to this site http://strobist.blogspot.com/2006/03/lighting-101.html. It offers a lot of helpful information.

[mdwsta4]

http://photonotes.org/articles/eos-flash/

i second strobist as i'm a regular reader and they offer invaluable advice.
using a flash is not difficult. what kind of flash did you get? are you using ITTL or manual? are you pointing it directly at your subject or difusing the light? how fast/slow of a shutter speed are you using?

[jmadigan]

This is a handy article about bouncing the flash, too:

http://www.diyphotography.net/four_ways_to_bounce_a_flash

[demonsmercy]

Thank you. the information is very precious.