Canon has released a firmware update for the 1D Mark IV. Firmware version 1.1.3 adds the following improvements and fixes:
- Enables the center AF point to autofocus when the camera is used with the EF 200-400mm f/4L IS USM Extender 1.4x lens and an Extender, whose combined maximum aperture is f/8.
- Fixes a phenomenon in which abnormal images may result when continuous shooting mode is enabled and the image size is set to “RAW” or “RAW+JPEG”.
You can download the firmware update and get instructions on how to install it here on Canon’s website.