Abbreviation: EX = "EX Lens" (Sigma)
The abbreviations means "EX Lens"
Explanation from Sigma
The exterior of this lens is EX-finished to denote the superior build and optical quality, and to enhance its appearance.
See examples of effected products
|Sigma EX 24-70mm f/2,8 DG HSM|
|Sigma EX 70-200mm f/2,8 APO HSM DG OS|
|Sigma EX 300mm f/2,8 APO DG HSM|