GX8 owners, I recently bought GX8. While reading through the user menu, I noticed that there's a "recording 4k photos" function (on P178 of the Advanced User Menu). I'm confused by the existence of such function. If I understand it correctly, 4k = 4096 x 2160 pixels. When setting aspect ratio to 4:3, GX8 produces an image size of 5184 x 3888. So why would anybody wants to shoot in 4k? Thanks!