Sigma has released firmware updates for seven Art and Contemporary lenses, along with updates for the MC-11 mount converter and the EF-630 flashgun.

The lens updates apply only to lenses with the Canon EF mount and to the following lenses:
18-35mm f/1.8 DC HSM (A013)
24-70mm f/2.8 DG OS HSM (A017)
35mm f/1.4 DG HSM (A012)
50mm f/1.4 DG HSM (A014)
85mm f/1.4 DG HSM (A016)
135mm f/1.8 DG HSM (A017)
100-400mm f/5-6.3 DG OS HSM (C017)
In each case, the new firmware addresses an issue that could cause continuous burst capture speeds to decrease with some camera bodies. The new firmware is available for downloading at

Sigma has also issued updated firmware for its MC-11 mount converters as well as an update for its EF-630 flashgun. The new firmware for the EF-E mount converter adds support for the just-updated lenses with their new 2.01 firmware. It also gains support for the Canon-mount version of the 105mm f/1.4 Art lens. The SA-E mount converter gains support for the Sigma-mount version of the 105mm f/1.4 Art lens and also the 70mm f/2.8 Art lens.
All of these updates can be installed using  Sigma Optimisation Pro ( Users will also need Sigma’s  optional USB Dock to update the lenses and the optional  Flash USB Dock for updating the flash.