The Simera 21mm f/1.4 FullFrame lens in black finish is designed for Leica M-mount cameras, offering an ultra-wide-angle perspective ideal for landscape, architectural, and interior photography. With its maximum aperture of f/1.4, this lens provides excellent low-light performance and shallow depth of field control. The optical construction incorporates two aspherical elements to minimize spherical aberration and distortion, three high-refractive index elements for compact design and reduced field curvature, and three extra-low dispersion elements that effectively suppress chromatic aberration and color fringing. This combination ensures consistent sharpness and accurate color reproduction across the entire image frame, from center to edges. The lens maintains the compact form factor characteristic of M-mount optics while delivering professional-grade optical performance. The black anodized aluminum construction provides durability and precise handling, with smooth manual focus operation and clearly marked distance and aperture scales. The 21mm focal length captures expansive scenes with minimal perspective distortion, making it suitable for both creative photography and technical applications where accurate spatial representation is required. The lens hood is included to minimize flare and protect the front element. Compatibility extends to digital and film Leica M-mount cameras, maintaining full mechanical and electronic functionality with supported camera systems. The optical design prioritizes high contrast and resolution even at maximum aperture, with performance optimization for both close and distant subjects. Filter thread size is 62 mm for accessory compatibility. This lens represents a balance between wide-angle coverage and fast aperture capability within the compact M-mount system.