Took the Lumix 12-35 out for a quick test shoot with the Panasonic AF-100. I mostly shot wide open and 5.6 from 12mm to 35mm. The lens is parfocal which I am very happy about. Performs very well and is nice and light. This ones a keeper. The range is just great. Equivalent to a 24-70 in 35mm world. This makes it my most useful lens I own for the AF-100 and lets not forget the GH2. For stills the 12-35 on the GH2 is sweet! OIS for hand held and again a great range.
Please visit my blog for more on the Lumix 12-35. eriknaso.com/2012/08/27/testing-out-the-panasonic-lumix-g-x-vario-12-35mm/
I wanted to make this a "test video" but I don't like shooting charts. Not my thing, so I added the F-stops and focal length for easy assessment. I hope it helps. Over time I'm going to add more shots to this test video but for know I think it shows this lenses capability.
As for zooming while shooting I didn’t test this. I will soon. The lens wasn’t designed to be a servo type lens but with a follow focus attached slow pushes and pulls might be possible. I will test this out soon and add this to the description.