NiSi 15mm f/4 Sunstar ASPH for Canon RF - The lens has an amazing 112° field of view which is wider than the regular angle of view for a standard 15mm focal length. It is actually equivalent to 14.5mm focal length! The housing is an all-metal construction that gives it durability and safety even in use in harsh environments. The focus ring has a ball bearing that handles smoothly and allowing comfortable and accurate adjustments. Both front and rear has 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 NiSi:s popular 100mm filter holder systems. This 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 a