SIGMA TELE CONVERTER TC-1401 and TC-2001 are dedicated to Tele Converter lenses, which should be used with only listed lenses.
The converter cannot be attached to the camera and lens whose mount is different.
Do not use the SIGMA TELE CONVERTER on top of another SIGMA TELE CONVERTER, or any other kinds of converters.
Attaching the APO Tele Converter to the Lens
First, attach the APO Tele Converter EX to the master lens. Then, attach the lens and the Tele Converter to the camera body. If you attach the Tele Converter to the camera body first it may cause a malfunction.