Any thoughts on the difference between the SLR Magic 10m on a GH4 vs a Tokina 11-16 with Speedbooster? With the Tokina, you'd get a touch more light and a wider FOV, plus the convenience of the zoom's range. Is there a big difference in image between the two? Trying to decide on one the other for an upcoming doc, to go along with my Pana 12-35mm and 42.5mm.