ShutterSpeedValue should be a signed rational
|Status:||Closed||Start date:||19 Jan 2010|
Revision 1960 added ShutterSpeedValue to the TIFF/EP tags, but its type was set to unsignedRational. I believe it should be a signed rational (see e.g. http://www.awaresystems.be/imaging/tiff/tifftags/privateifd/exif/shutterspeedvalue.html).
I am attaching a patch against svn trunk.