Tom Antos just made/posted a rap video (and a quick anamorphic tutorial) he made with a 12-35 F2.8 (he said he never went over 20mm) and the SLR Magic Anamorphot 1.33 on GH4. It's obviously a low budget project but the image quality is pretty decent, IMO.
Here it is in 1080p.
https://www.youtube.com/watch?v=9I0eSW7lqbk&feature=youtu.be
Here it is in 1080p.
https://www.youtube.com/watch?v=9I0eSW7lqbk&feature=youtu.be

