New answers tagged shadows
It could still be your shutter speed (since you didn't say you tried different shutter speeds). To test this, take at the exact same exposure settings but without flash. If the top of your picture looks the same as the top of this one (in the shadow) then it's still your shutter speed being too fast. Or another test is to just put your shutter speed ...
What you are describing is called Dodging (to lighten) and Burning (to darken) in Photograph, techniques that come all the way from shooting and developing film. Photoshop have specific tools for doing this, but the way I like to do it is non-destructively - try using this as a guide: http://www.photoshopessentials.com/photo-editing/dodge-burn/
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