DC: DC FOR DIGITAL
These are special lenses designed for APS-C size sensors so that the image circle matches the smaller size of the image sensor of most digital SLR cameras. Their specialized design gives these lenses the ideal properties for digital cameras, the compact and lightweight construction is an added bonus!
HSM: QUIET & FAST AUTOFOCUSING
This lens uses a motor driven by ultrasonic waves to provide a quiet, high-speed AF.