11mm f/4.0 Firefly Pentax

11mm This extremely wide angle, rectilinear manual focus lens designed for DSLR cameras, and is an extremely wide Full Frame rectilinear lens with a 126° angle of view. 4 high refractive lenses, 2 ED lenses and 3 aspherical lenses guarantee minimal distortion, as low as 3.13%, making our 11mm f/4.0 lens absolutely unique in its class. Each Irix lens is equipped with a weather sealed construction which protects the interior against dust and moisture. Thanks to inner seals, our lenses are also protected from accidental water splashes. Firefly is the standard version equipped with three rubber seals that protect camera mount and focusing mechanism against dust, moisture and side accidental water splashes. Ergonomic focusing ring with rubber grip offers the freedom to operate with the camera. It is the most lightweight lens in its class. Image Size 35mm 'Full Frame' Focal Lenght 11mm Field Of View 126° (Diagonal) Focusing Range 0.275 M (0.9 Ft) ? Focusing TypeManual With Lock Function and Focus Confirmation Aperture Range F/4 – F/22 Aperture Control Via Camera Aperture Shape  9 Rounded Blades Lens Construction 16 Elements In 10 Groups 4X Hr, 2X Ed, 3X Asp Front Filter Thread No Rear Filter Thread 30 x 30mm Dimension 118 x 100 mm (4.49” X 4.05”) Weight 730g 790g