This is an old Canon FD prime lens with max aperture of f 3.5. It is attached to the GF-1 using a cheap fd to m4/3 adaptor. Given the sensor size, the lens registers at a focal length of around 260mm. This, along with the size and weight compared to the camera makes for some exaggerated shakiness - not helped by the lack of integral image stabilisation on the GF-1. Some support is vital for a sharp picture.
As far as sharpness and detail is concerned, this £15 ebay bargain outperforms the native 14-45mm lens that came with the camera (as do all my other 35mm prime lenses).