> I currently have the 420EX flash for my 20D. Was told that
> maybe it's not strong enough for the camera? I am having
> issues indoors with lighting so thought this might be part
> of the problem? PLMK your thouhgts and opinions.
> Thank you

Whether the 420EX is "strong enough" depends on the subject
you are shooting, the distance from the flash to the subject,
the ISO setting on your camera, and the aperture setting of
your lens.

In other words, some more information would be more helpful.

Cheers
Julian Loke