Edge Consistency (Panasonic)
One premise of this review is that the 7mm setting – the widest angle – is what makes these lenses matter. There are much cheaper options even at 9mm, let alone 14mm. So, we've paid particular attention to the 7mm setting, and as we look at corner performance, we're showing results exclusively from that focal length. What we see at 7mm is much worse than what the lenses can do at 10mm or 14mm. Our field test shots were taken at f/6.3 at 1/160s, on a tripod.

In short, the Olympus's resolution falters in the corners, with a sort of smearing effect that looks like motion blur. The Panasonic holds up better, but still takes a hit towards the edges of the frame. Both lenses show significant color fringing, but the Olympus is better on that score. We noted in the review of our lab tests for resolution that at the center of the frame, both lenses perform best wide open, or nearly so. That's not true in the corners.

The sample images below show the relative corner performance of the two lenses at 7mm, f/4.
 

Olympus Zuiko 7-14mm @ 7mm

Panasonic Lumix 7-14mm @ 7mm