Sigma 1.4x EX DG APO Teleconverter Sigma Fit

The 1.4 EX is placed between the lens and the camera, and it 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.

Price: 199.00 from Wex Photo Video