Anyone tried the Panasonic 25mm f/1.4 Four Thirds Lens on the GF1? It's a well rated lens to be sure, and hard to come by. How vast would the difference be between what is possible with the pancake 20mm f/1.7 and the 25mm f/1.4? What would be the downsides on a non-:43: lens like this other than having to use an adapter and that it's bigger and heavier than the much more compact 20mm? What would be a top-notch adapter for 4/3 to :43: ? Thanks.