Compatible with Canon EOS 35mm SLR Cameras
Tamron Standard Teleconverters
The standard Tamron teleconverters extend the focal length by a factor of 1.4 or 2 respectfully and sustain the same light loss factors as the Pro-series. Though using a teleconverter on wide-angle lenses is never really recommended, these converters can be used with lenses that are wider than 90mm and are ideal for all lenses that are not F/2.8's
The 1.4X teleconverter will increase the focal length of the master lens by 1.4X and make the lens one f-stop slower. The 2X doubles the focal length of the master lens and makes the lens two f-stops slower. In addition to increasing focal length, both teleconverters allow greater magnification in macro since the Minimum Object Distance (MOD) of the master lens does not change when used with the teleconverters.
The 1.4X teleconverter can be used with both AF and MF lenses. AF will be retained if the master lens is F/4.5 or faster. AF will be retained with the 2X teleconverter if the master lens is F/4.0 or faster.