Large aperture telephoto lenses work brilliantly with teleconverters and they are a great little tool if you want to extend your reach whilst keeping costs and weight down.
The Canon EF 1.4x III extender increases the focal length of Canon L-series telephoto or telephoto zoom lens by a factor of 1.4x, with higher AF accuracy and improved communication between camera and lens.
Ideal for press, sports and nature photography, the Canon EF 2x III extender increases the focal length of Canon L-series telephoto or telephoto zoom lenses by a factor of 2x.
The Sigma 1.4x EX DG teleconverter for Canon is placed between the lens and the camera, and the high optical performance is maintained.
By mounting the Sigma 1.4x TC-1401 teleconverter between a telephoto lens and camera, the focal length of the lens becomes magnified by 1.4 times.
The Sigma 2.0x EX DG teleconverter for Canon allows the photographer to double the focal length of a compatible lens.