The Sigma 170-500mm f/5-6.3 APO DG Aspherical lens is a compact aporchromatic ultra telephoto zoom lens that covers the range up to 500mm, and is ideal for sports, nature and landcape photography.
This lens combines a 5 lens group zoom system with an aspherical lens element to deliver sharp high contrast images throughout the entire zoom range. Using Sigma's apochromatic lens design and three SLD glass elements, the aberrations usually found in ultra-telephoto lenses have been eliminated.
One aspherical lens and three SLD glasses are used for correction of chromatic aberration. Color aberration in the secondary spectrum is compensated by using three pieces of Special Low-Dispersion glass (SLD), and making high-quality images a reality throughout the entire zoom range.
The five-group zoom and rear focus systems ensure high performance stability and ease of use
Front lens group doesn't rotate, which makes using polarized filters more convenient
A convenient built-in rotary tripod mount eliminates vibration during shutter release