That is nice timing Phil I just came on looking for examples of screen grabs from the Gh4 , that image certainly fits the bill
. Though it doesnt help my resistance to buying anymore mFT cameras till we get better stills , oh well its only money 
Still waiting for mine. Maybe by the end of May, I hope!
Yep just downloaded the full sized 8MP image and opened it in Photoshop to pixel peep. Really sharp image at 100%. Now I can say to my photographer friend when he asked if you can still take photos with the GH4 while doing video: No need. Just pull some frames haha.
Definitely a plus of 4K video vs. HD (which will give a 2 megapixel image from a frame grab). Apparently Panasonic appreciates that advantage; they provided instructions on how to do it: http://service.us.panasonic.com/opermanpdf/DMCGH4 _CSG.pdf
Apart from the fact that the sort of shutter speeds that look good on video make for bad stills and vice versa. To pull reasonable stills from video you have to shooting with that intention in mind.
I don't really agree with this. If you step through a video (shot with the normal shutter angle) frame by frame you see some that are very blurred and others that are very sharp. I did this recently with some fashion show footage including a dance routine, so not entirely static subjects.
But you want to control which frames that should look sharp. You don't want the decisive moment to be blurry.
