The Canon 35mm f/1.4L II lens announced back in August 2015 was the first Canon lens to feature the company’s new Blue Spectrum Refractive (BR) lens technology, a special lens element that corrects for color fringing.
Canon just released the 1-minute video above that provides an explanation of what this new BR lens technology is and how it works.
The BR lens element is made of an organic optical material developed by Canon and is combined with concave and convex lenses to form an enhanced lens element that helps to focus all visible light onto a single point.
Traditional lenses have a hard time correcting blue wavelengths, which leads to blue fringing in photos. BR lenses help to minimize this chromatic aberration:
Canon is also working on a Canon EF 600mm f/4 DO BR lens with this same technology. The company showed off a prototype of that lens at Canon Expo late last year.