http://www.dpreview.com/news/0809/08091704canon_ef24mm.asp#coating 有英文原理說明及圖解:

The 24mm F1.4 L USM II sees the debut of Canon's new 'Sub Wavelength structure Coating' (SWC) technology. Considered by Canon to be considerably more effective then their existing 'Super Spectra Coating', the new coating is applied to the inside surface of the front lens element, and is designed to minimize flare and ghosting caused by secondary reflections between the sensor surface and the lens elements, which can lead to significant image degradation in digital SLRs.

The new biomimetic coating is inspired by features found within the eyes of moths, and uses a nano-scale structure to reduce dramatically the amount of internally-reflected light in lenses that contain large curve-radius elements. It is therefore particularly effective with fast wideangles such as the new 24mm F1.4L II USM.

用途是減少CMOS及鏡片間產生的耀光及鬼影. 也有用到奈米分子. 感覺和Nikon的技術很像.