Cooke S5i

The lens aperture is T1.4, which allows you to shoot with natural light. There is an illuminated focus ring for working in the dark.
Cooke 5/i lenses are designed to produce images with high detail and contrast, low distortion, spherical aberrations and flare. Modular lens design improves ease of maintenance and repair.
They are compatible with Cooke S4/i, miniS4/i, CXX 15-40mm T2 S4/i Zoom, 18-100mm T3.0 and 25-250mm T3.7 and SK4 16mm lenses.
Lenses are made of special alloys that are least subject to thermal expansion and contraction – this allows you to work comfortably in any climatic conditions. Cooke lenses are equipped with /i technologies (transfer of metadata to a flash card). All Cooke 5/i lenses have a common fixed front diameter of 110mm.