Lens coating

How it works

An uncoated air-to-glass surface reflects around four percent of the light hitting it. A lens with ten such surfaces loses a large fraction of its light to reflections that bounce around inside and reappear as veiling flare and ghosting.

A single coating cuts that reflection to roughly one percent. Multicoating, which arrived on consumer lenses through the late 1960s and 1970s, takes it far lower across the visible spectrum. Makers branded their versions: Zeiss T*, Pentax SMC, Fujinon EBC, Canon S.S.C.

This is the single largest practical difference between an early and a late version of the same optical design. The formula may be identical while contrast and flare resistance are visibly better on the coated version.

Why it matters when buying

When two versions of a lens share a design, the multicoated one is usually the better shooter and the earlier one the better character lens. Shooting into the light is where the difference shows most.