dash cam location / mount advice

I recently had a V5 dash camera installed with adhesive (no mount) about 1/2 inch centered under the stem of my rearview mirror.  Especially during the day, I notice a bit of a shadow in some of my photos and videos.  I thought at first that it was coming from the lens itself, but imagine it is likely from the mirror. This is my first dash camera.  What is the best location for installation in a compact car?