Panasonic Lumix G X Vario 12-35mm / F2.8 ASPH.
The Lumix G X Vario 12-35mm F2.8 ASPH OIS is a premium image-stabilized zoom for Micro Four Thirds cameras, offering a classic 24-70mm equivalent focal length range. It’s tiny for an F2.8 zoom, and features weather-sealed metal-barreled construction. The 12-35mm is designed for both stills and movie use, with a near-silent stepper focus motor for silent, fast autofocus.
Description from DPReview