I've bought a Lumix GX7 and want to buy an ultra wide angle zoom lens. The obvious choices are: 1. Olympus M.Zuiko Digital ED 9-18mm f/4.0-5.6 - about £430 (UK) 2. Panasonic G 7-14mm f/4.0 - about £820 (UK) The Olympus lens is significantly cheaper and performs well apart from some issues with chromatic aberration under certain conditions. What are people's experience of using the Olympus lens in a Lumix body? Are there any significant advantages of using the Panasonic lens considering it is almost twice the price?