Sigma 50-500mm f/4-6.3 DG lens

The Sigma 50-500mm 4-6.3 EX DG HSM is a super-telephoto zoom lens produced by Sigma Corporation. It is commonly known as the "Bigma" because of its long and heavy body. It contains four SLD (Special Low Dispersion) glass elements to provide correction for chromatic aberration. It is aimed at advanced consumers.

Versions
The Bigma was originally announced by Sigma in 2000 at that year's Photo Expo and released in 2001. The lens has a variable minimum focusing distance and varifocal design, which was remedied partially through autofocusing technology.

Over the years, it has gone through several iterations and improvements. This includes the 2006 DG model which has upgraded coatings optimized for digital cameras. In 2010, Sigma added built-in optical stabilization (OS) to the Bigma.