Firmware update v1.01 for Sigma 18-35mm f1.8 Art (for Canon) enables Autofocus to work at all apertures
This guide leads you through the firmware update process for most Sigma lenses, in this case the Sigma 18-35 f1.8 Art lens for Canon.
The latest firmware for the 18-35 features Autofocus for the Canon C100 DualPixel Autofocus for the complete aperture range of the lens (before Firmware 1.01 autofocus was only working with f1.8).
Short test video with the updated Sigma 18-35 on the Canon C100
The Sigma Dock
Second thing you need is the free Sigma Optimization Pro software (available for Windows and Mac OS) which is the lens maintainance and firmware update software from Sigma.
Sigma 18-35 f1.8 Firmware
Firmware Update | SIGMA Optimization Pro
[ Art | 18-35mm F1.8 DC HSM | 013 | For CANON EF Mount ] –
Firmware Version 1.01
New: Autofocus is supported at any aperture value when used with the Canon Digital Cinema Camera EOS C100.
SIGMA Optimization Pro Features & Firmware update
With the lens connected to the adapter and the latter connected to you computer you can start the software which will immediately check for updates for the USB Adapter and than for the lens attached to it.
The software updates the firmware of the adapter first and than asks if you want to update the firmware for the lens.
The autofocus for the lens can be finetuned if necessary. When finished press the Rewriting button to write the changes back to the lens.
After that, the USB can be unpluged and the lens can be used as normal.
When the lens is used on a Canon C100, DualPixel autofocus works as aspected for all apertures from f1.8 up to f16 nice and smooth with this amazingly sharp Sigma 18-35 f1.8.
Also take a look at the Sigma 24-105 f4 which has a better image quality than it’s Canon L-Series pandant (minus weather sealant).