Distinguished by its refined physical construction, the 11mm f/4 Blackstone Lens from Irix is an ultra-wide prime designed for Nikon F-mount DSLRs. As a rectilinear lens, the advanced optical layout makes use of aspherical, extra-low dispersion, and high-refractive index elements to control distortion and aberrations for accurate, and sharp rendering with a high degree of clarity and color accuracy. Additionally, a Neutrino coating has also been applied to the lens to control flare and ghosting for improved contrast when working in strong lighting conditions.
Beyond its optical assets, this 11mm f/4 lens also sports a manual focus design for fine-tuned control, and incorporates a unique positive focus lock to secure the focusing position at any point for consistent, repeatable shooting. As the Blackstone version of this focal length, this lens is also distinguished by an aluminum and magnesium alloy exterior, engraved lens markings with fluorescent UV paint for high visibility, and extensive weather-sealing about the lens to permit working in harsh environments.
- The Blackstone version of the 11mm f/4 lens features a durable aluminum and magnesium alloy housing and weather-resistant exterior along with inner seals, and an extra seal at the front element, to protect against dust and moisture intrusion. The metal exterior also distinguishes itself with an anti-scratch finish, and sports engraved focus distance and depth of field scales with fluorescent UV paint for high visibility when working in low-light conditions.
- Ultra wide-angle prime designed for FX-format Nikon F-mount DSLRs, this lens can also be used on DX models where it provides a 16.5mm equivalent focal length.
- Three aspherical, four high-refractive index, and two extra-low dispersion elements are featured within the optical design to limit both spherical and chromatic aberrations, as well as color fringing and distortion, for improved clarity, sharpness, and even illumination.
- A Neutrino coating has been applied to limit lens flare and ghosting for improved contrast and color fidelity.
- Manual focus designed is benefitted by a positive focus lock mechanism to secure your focus position at any point to limit unwanted shifting of focus.
- A hard click stop indicates the infinity position on the focus ring for easy use in low-visibility conditions.
- Large depth of field scale benefits using hyperfocal and pre-focus techniques.
- Built-in petal-shaped lens hood blocks stray light in order to reduce lens flare, and also protects the front element of the lens.
- Rear of the lens accepts 30 x 30mm cut gel filters.
- Rounded nine-blade diaphragm contributes to smooth bokeh.