Lens Sigma Teleconverter 2x

ns Lens Sigma Teleconverter 2x :
Sigma - 2.0X Teleconverter for Canon mount.
Using the APO Tele Converter EX decreases the effective aperture by one f-stop with the APO Tele Converter 1.4X EX and by two f-stops with the APO Tele Converter 2X EX. However, exposure can be determined in the same manner as when using the master lens without a tele converter.
If using a lens marked *1 in the table, the camera's display will give you the converted exposure information. When using a lens not marked *1 in the table while using a hand held exposure meter, you should increase the exposure reading by one f-stop for the APO Tele Converter 1.4X EX and by two f-stops for the APO Tele

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