The Kenko 20mm Extention Tube DG is an accessory exclusively designed for use with standard AF lenses to shoot subjects at closer distance with higher magnification. Magnification ratio for Tube 20 is about .4 closer with 50mm standard lens.
Provides perfect coupling with automatic aperture, TTL metering and AE mechanism.
This DG Extension tube has upgraded "Gate-Array IC" circuitry to work better with digital SLR's and some of the digital SLR lenses.