I just tested my Olympus 17mm lens against my Panasonic 20mm lens, both on the G1 and GH1 bodies. I've done all the firmware updates for both bodies and lenses. The test protocol was simple: 1) Focus on a distant target 10 feet away 2) Aim camera at running internet stopwatch (3 feet away), wait for a whole second to change on the stopwatch, pull the shutter 3) Use the time in the captured photo to determine the entire lag, most of which is attributable to the autofocus time I repeated this multiple times and came up with the same average result for both lenses, within 0.05 seconds of each other (within the error of the test). The 17mm Zuiko quickly focuses past the subject twice before stopping on the target (3 quick moves) whereas the 20mm Lumix focuses in one, slow movement. The total time for autofocus is remarkably even though. Same on G1 and GH1.