The dedicated 1.4x APO Teleconverter features a high performance 5 element/3 group optical design, and it is optimized for use with long telephoto and telezoom lenses.
The high performance optical characteristics of these teleconverters maintain the optical performance of the compatible lenses with which they can be used.
Sigma APO Tele Converter 1.4x and 2x are dedicated Tele Converter lenses, which should be used only with the listed lenses. The 1.4X Convertor will fit the following lenses 180mm f/3.5 APO MACRO EX HSM - MF 300mm f/2.8 APO EX HSM - AF 300mm f/4.0 APO MACRO - MF 400mm f/5.6 APO MACRO /HSM - MF 500mm f/4.5 APO EX HSM - MF 800mm f/ 5.6 EX HSM - MF 70-200mm f/2.8 EX HSM - AF 70-210mm f/2.8 - MF 50-500mm f/4-6.3 APO - MF 100-300mm f/4 EX HSM - AF 120-300mm f/2.8 EX APO - AF 300-800mm f/5.6 EX APO - MF Will also fit the following Orginal Canon EF Lenses 200mm f2.8L USM - AF 300mm f2.8L USM - AF 300mm f4.0L IS - MF 400mm f2.8L USM - AF 400mm f5.6L USM - MF 500mm f4.5L USM - MF 600mm f/4L - MF 70-200mm f2.8L USM - AF
On the lists, the lenses marked "AF" will retain auto focus operation when used with a Tele Converter. The lenses marked "MF can only be used for manual focus.
Please refer to the manufacturers Teleconverer Matching List for an updated compatability chart. http://www.sigma-photo.co.jp/english/acc/condaitr.htm
