According to DxOMark test, the lens has a a peak sharpness of 7 P-Mpix on the Olympus OM-D E-M1, a 16-Mpix model without an AA filter.
Panasonic Lumix G 25mm f/1.7 ASPH Lens Gets DxOMarked
Panasonic LUMIX G 25mm F1.7 ASPH. vs Olympus M.ZUIKO DIGITAL 17mm f1.8 vs Olympus M.ZUIKO DIGITAL 17mm f2.8
From DxOMark conclusion:
Although it performs quite, well it doesn’t really stand out. And there are some concessions, most notably in sharpness. While experienced photographers know sharpness isn’t everything in a lens, it feels like a somewhat retrograde step. Nevertheless, as a model intended to entice users to upgrade from a kit zoom, it is an attractive option.
Panasonic Lumix G 25mm f/1.7 ASPH ($249 – Amazon | B&H | Adorama) lens for mirrorless cameras with Micro Four Thirds image sensors has an iris diaphragm with 7 rounded blades for a pleasing rendering of the out-of-focus areas.
An inner focus drive system and stepping motor designed for smooth, silent operation work with the camera’s high-speed, high-precision contrast-detect AF system for both photo and video recording. Weighing in at 125 grams, the new 50mm equivalent Micro Four Thirds lens features 8 elements in 7 groups, including 2 aspherical elements and 1 ultra-high-refractive-index element.