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 full-frame Pentax K-mount DSLRs, this lens can also be used on APS-C 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.