Shootout at 25mm on Olympus E-M1: 12-40mm f/2.8 PRO, SHG 14-35mm f/2.8, 25mm f/1.4 DG Summilux
Added to my review of the Olympus E-M1 in Guide to Mirrorless is a field comparison of the Olympus 12-40mm f/2.8 PRO, the Olympus SHG 14-35mm f/2 and Panasonic Leica 25mm f/1.4 DG Summilux.
Shootout: Olympus E-M1 at 25mm, Yellow Wagon