Leica Lens Performance for All LUMIX Micro Four Thirds Cameras: Strict LEICA quality standards now in a F1.7 Micro Four Thirds (MFT) camera lens for professional photographers and videographers. Exceptional optical performance Across the Full Zoom Range: Bright F1.7 aperture is available across the entire zoom range of 25-50mm. Stepless Aperture for Smooth, Even Brightness: A stepless aperture ring and micro-step drive aperture system ensure optimal, consistent light when zooming or panning. Minimize Image Shifts During Zooming: The optical design achieves exceptional barycentric stability to minimize image shifts during zooming. Rugged Design: Dust/splash*/freeze-resistant design withstands heavy field use under harsh conditions. *Dust and splash resistant does not guarantee that damage will not occur if this lens is subjected to direct contact with dust and water