Leica Summarit-S 35mm f/2.5 ASPH CS Lens

The Leica Summarit-S 35 mm f/2.5 ASPH. functions as a versatile wide-angle lens, offering a field of view equivalent to that of a 28 mm lens in 35 mm format, which results in strikingly dramatic perspectives. Its notably fast maximum aperture provides exceptional creative opportunities for selective focusing, allowing photographers to effectively separate subjects from their backgrounds. Additionally, the alternative CS version, featuring a central shutter and a close focusing limit of just 55 cm (approximately 1.8 ft), enhances its adaptability for various photographic applications.

Achieving the combination of a rapid maximum aperture and a broad angle of view necessitates significant investment in the design and manufacturing of the lens. Leica leverages its extensive experience in producing lenses with aspherical surfaces, a characteristic that is seldom found in lenses of such large diameter. The front group incorporates a lens with an aspherical surface, meticulously crafted through a precise grinding and polishing process to ensure minimal distortion, while another aspherical surface is utilized in the rear groups. In total, five of the eleven lenses arranged in nine groups are constructed from glass with anomalous partial dispersion, and three are fluoride lenses known for their exceptionally low dispersion characteristics. The rear group focusing mechanism in this splash-proof and dust-sealed lens guarantees consistent imaging quality from infinity to the closest focusing distances, maintaining a constant length during focusing.

The unique design of the Summarit-S 35 mm f/2.5 ASPH. results in outstanding image quality, even when used at its maximum aperture. Stopping down the lens only marginally enhances the performance in the corners of the images. With a vignetting measurement of merely 1.4 stops and distortion limited to 1.7%, even at the closest focusing distance, these factors are virtually unnoticeable in practical applications. The significant effort dedicated to the lens's design and construction culminates in a wide-angle lens that empowers photographers to fully harness its creative potential without any compromises.

This version of the lens features a central shutter, commonly referred to as a leaf shutter, integrated into its design. This central shutter enables the S camera to synchronize with a flash unit at any shutter speed, up to and including 1/1000th of a second. As a result, photographers gain exceptional control over the balance between ambient light and strobe lighting.