"The extremely wide Full Frame rectalinear lens with an angle of view of 126deg.. 4 high refractive lenses, 2 ED lenses, 3 aspherical lenses guarantee a very low distortion of 3,13% which makes this lens unique in its class. The Focus Lock system, special weather and dust sealing, the Infinity click, a rear filter slot are all combined in the solid aluminium alloy construction that makes Irix 11 mm lens unbeatable tool for landscape, architecture, nightscape and extreme photography (images). The Irix 11mm f/4 Firefly has an innovative Focus Lock, ideal for when you are working with longer exposures and you need to maintain the focus in the same position. One small movement and a whole day's work could be lost, but with this new innovation, you will keep your focus exactly where you want it.|Ultra lightweight design, with weather sealed construction, to resist elements in the harshest conditions|Angle of view of 126deg. and a focus distance of 0.275 m (0.9 ft)|Ergonomic focus ring, for more comfortable focusing|Clearly-labeled infinity position for the focus ring with a noticeable click-stop to make it easy to find, even in the dark|4 highly refractive lenses (HR), 2 ED lenses and 3 aspherical lenses guarantee minimal distortion, as low as 3.13%|Rear gelatin filter slot for 30x30mm filters lets you be even more creative"