Hello, I just sold my Panasonic 25 1.4 and I want to go for Metabones Speedbooster XL m43-Canon and for some 7-800Euro lens (new or maybe used). I have a GH4 and I want to make interviews and film in the coffeeshops (a coffee blog project) Today, in october 2015, there is a better lens for my purpose, comparing with the Sigma 18-35 1.8? I prefer a fast aperture and a variable ND filter, because the bokeh is better. On my Summilux 25 1.4, at F1.4 the background seems almost clear, at 2-3meters between subject and background. I make an experiment with Canon 6D and a Sigma lens, and at F2.0 the backgrond is almost blured, at the same distance to the subject. So, when the people say "GH4 with m4-3 lenses deliver a clinical image, like tv news" they are right.