7artisans 75mm F1.25 lens optics contains 7 elements in 6 groups and is based on Sonnar formula. This is smallest F1.25 portrait lens in the world and it is compatible with rangefinder camera and mirrorless camera. The optimized modern algorithm and polishing technology, we can guarantee the high precision of large size glass while in production. Wide Compatibility: 7artisans 75mm F1.25 Compatible for Leica M-Mount Cameras. We use lots of brass structural components for the lens to combine the size and solidity. The weight of 600g makes sure that it’s comfortable to rotate the focus ring. The special compressed bokeh of 75mm is more dramatic than that of 35mm and 50mm. And we can create portraits under different lighting conditions with super large aperture.