The 1.4 EX is placed between the lens and the camera, and allows the photographer to use the 70-200mm f/2.8 lens as a 98-280m f/4 lens, and the 300mm f/2.8 lens as a 420mm f/4 lens; the high optical performance is maintained and the AF speed is not affected.
|Lens construction||5 elements in 3 groups|
|Focal length||1.4x that of a master lens|
|Aperture coupling range||F2.8 - F32|
|Reproduction ratio||1.4x that of a master lens|
|Dimensions||68.5 X 19.5mm
(2.7in. X 0.8in.)
*Dimensions and weight include the SIGMA mount.