By the looks of the 'shadowing' (or more accurately lack of any), there's a very high possibility that the flash head was bounced off the ceiling, and possibly a diffuser dome was also used.
Normally, when flash is used,
ISO is kept to an absolute minimum, and the flash is supposed to control the
exposure.
When you bounce flash you lose a lot of the power of the flash. It makes for much less and softer looking shadows, but the power loss is huge. If you did bounce your flash, did you go the 'whole hog' and set it to 90°? If so, try opening up the angle a bit more to get a bit of direct
light from the flash as well as some bounce, or use a white card to re direct a bit more
light towards the subject, if you maintain that 90° angle. I think the 580 model is a high end flash from
Canon, so it may have an inbuilt pop out whitecard. If you open this up whilst the flash head is at 90°(instead of using a diffuser dome), you'd be surprised at how much extra
light throw is directed towards the subject in front of the camera
That is, if you set the camera to ISO200 or 400 for example, the flash will then create more
light to compensate.
Also of note is that in the exif data, is that the program mode used in the camera is listed as Normal mode!
Normal??? Normal relative to what? .. Is there an abnormal setting too?
Was that manual mode? did you set all the variables in the camera yourself, or was it all automagic?
For exif viewing: If you can find a 'front end' to ExifTool for Mac, then this is probably the ideal solution for exif data management.
My only issue with exiftool is the commandline interface. For Windows there is ExifToolGUI and GeoSetter that both use it to view and/or edit exif data.. I have no idea on what is available for Mac tho!
ExifTool itself runs on Mac, so if you feel comfy with using command line go for it.