Canon’s ‘Luxury’ range of lenses. These typically incorporate Ultra Low Dispersion and fluorite elements to help control chromatic aberration, as well as aspherical elements to help counter distortion and spherical aberration. Canon also claims that these lenses are built to a high standard, not just for longevity but also to protect them against inclement weather. L lenses can be recognised by a red ring towards the top of their barrel, while some of the longer telephoto lenses also sport off-white barrels, designed to reflect heat.