Abbreviation: EF-S = "Electro-Focus Small Image Circle" (Canon)

The abbreviation EF-S means "Electro-Focus Small Image Circle" and is seen on Canon products.

Explanation from Canon

EF–S lenses are specifically designed for EOS DSLR models with a more compact sized sensor – delivering lenses that are lightweight, versatile and supremely portable. With the EF–S range, Canon’s engineers took advantage of the APS–C sensor size to produce lenses that are not only lighter and smaller, but also offer photographers far greater wide-angle choice. Owners of EF–S mount cameras have access to a complete offering of lightweight lenses extending from 16mm to 400mm (35mm equivalent).

See examples of effected products

	Canon EF-S 18-200mm F3.5-5.6 IS
	Canon EF-S 55-250mm F4-5.6 IS II
	Canon EF-S 17-55mm F2.8 IS USM

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