Originally Posted by Ratbert
While it's true that they 'canna change the laws of physics', better optical elements mean better optical quality. For example, all L-series primes contain an aspherical lens element to reduce spherical aberration, and all L-series zooms contain a UD or fluorite element to reduce chromatic aberration. It's true that non-L lenses can have these elements (except for fluorite), but even then quality matters - for example, the aspherical elements in L-series lenses are ground and polished glass (highest optical quality), whereasin the non-L lenses with aspherical elements, those are molded glass, molded plastic, or a resin coating on a spherical glass element (in decreasing order of quality and cost).




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