Abbreviation: ASP = "Aspherical Lens" (Sigma)
The abbreviations means "Aspherical Lens"
Explanation from Sigma
The aspherical lens complex allows freedom of design, improved performance, a reduced number of component lenses and a compact size.
This lens provides high optical performance while maintaining a compactsize. For example, the 12-24 mm f/4.5-5.6 EX DG ASPHERICAL lens widensthe range of wide-angle lenses, and it provides distortion-free images withimage reproduction performance equivalent to that of a single-focal lengthlens. Aspherical lenses allow the production of high-quality images fromcompact, lightweight telephoto zoom lenses.
See examples of effected products
|Sigma EX 24mm f/1,8 DG ASP Macro|
|Sigma EX 20mm f/1,8 DG ASP RF|
|Sigma EX 28mm f/1,8 DG ASP Macro|