The lens has an impressive 112° field of view, wider than the regular angle of view for a standard 15mm focal length. It is actually equivalent to a 14.5mm focal length!The housing is an all-metal construction that gives it durability and safety even in harsh environments. The focus ring has a ball bearing that handles smoothly and allowing comfortable and accurate adjustments. Both the front and rear of the lens have matt paint anti-reflection and to avoid glare.The front has a 72 mm thread, and it supports standard 72mm circular filters and, of course, NiSis popular 100mm filter holder systems. It allows you to shoot while experimenting and enjoying the use of filters with ease.Optical construction consists of 12 elements in 10 groups and has one double-sided aspherical element and two extra-low dispersion elements for best optical performance. Thanks to the optical construction, the lens produces minimal chromatic aberration, distortion, and vignette.The lens utilizes anti-reflection film technology to improve light transmittance and reduce lens flare and stray light.Thanks to the ten straight aperture blades, the lens can produce starbursts from f/4 to f/22, and due to the optical construction, there is no glare in the starburst. This function breaks the paradigm of requiring a small aperture to create a starburst.The minimum focal distance is 0.2m that helps you create a stunning visual impact for close-up foreground subjects in your images. Key specifications Great optical performance 10 straight aperture blades the lens can produce starburst from f/4 to f/22 Optical construction consists of 12 elements in 10 groups and has one double-sided aspherical element and two extra-low dispersion elements Minimum focal distance is 0.2m 72 mm front thread for standard filters