Flare (Panasonic)
The Olympus and Panasonic 7-14mm zooms look as though they'll have terrible problems with flare. Their front elements stick out of their mounts nearly ¾ of an inch. It just looks as though light from all directions will drop onto that glass and bounce around inside, and the lenses' contrast will droop like a cornflake in milk.

The great thing is that both lenses are well corrected for flare. In the lab, we use Imatest software to measure flare. The crafty test target is a step wedge, mounted on a card with a hole in it. Behind the hole, deep in shadow, there's a swatch of black velvet. The test looks at the step wedge to measure how the shot is exposed, and it looks for any tone at all in the image of the black hole. Any tone at all is a mistake – even the darkest gray is light from elsewhere in the frame, or bouncing around the glass, contaminating the Stygian blackness that should be there.

The Panasonic lens performed best in our flare test. Its best trial registered 0.362 percent veiling glare, while the Olympus's best performance was a less impressive 0.917 percent.

Veiling glare results: Panasonic Lumix 7-14mm

Veiling glare results: Olympus Zuiko 7-14mm

We also noted better performance from the Panasonic in the field. We were able to shoot closer to a light source while avoiding flare with the 

Panasonic than with the Olympus.

Shooting on a sunny afternoon, we were able to set up shots such that the sun wasn't in the shot, but the lenses themselves were in direct sunlight. Our guess had been that the shots would be spoiled by localized flare. We're pleased to say that both the Olympus and the Panasonic can tolerate a little light on the lens without creating those distracting and odd forms. The Panasonic can do a bit better than the Olympus.

Both lenses have built-in shades. The zoom mechanisms extend and retract the shades, apparently to optimize their performance. The shades aren't perfect by any means. We found that we could add a little extra shade on the lens with our hands, and cut out flare without blocking the image. If we owned either lens, we'd plan to use it on a tripod, and set up an adjustable gadget to hold a flag (a little black shade) in just the right spot.