Zoom range 28 to 600mm (FF eq)
The entire zoom range of 28mm to 600mm (FF equivalent) can be covered with just two lenses, the GX7 kit 14-42mm and a 45-175m G lens plus a 1.7x converter, the Sony HGD1758 (which requires a 46 to 58mm step-up ring).
The 45-175mm lens zooms and focuses internally so it can easily support the weight of the converter. There is no noticeable vignetting and the AF is very fast. Unlike legacy tele lenses the IS works very well at all focal lengths and the AF capability is retained. The following image was taken at f/5.5 with a GX7 at about the mid zoom setting.
The 45-175 lens plus converter weighs only 785 grams and is 17 cm long so it is tiny compared to a FF 600mm lens.