Canon today has released firmware updates for the Canon EOS-1D Mark II and EOS-1Ds Mark II that are designed to improve AI Servo autofocus accuracy when tracking moving subjects in low light, among other changes.
Changes in version 1.1.0 of the firmware for the EOS-1D Mark II include reducing camera startup time from 0.5 to 0.3 seconds and adding support for the WFT-E1/WFT-E1a wireless transmitter.
The main focus (pun intended) of this update, however, is to rework the AI Servo algorithm to improve tracking performance in low light levels and/or when the subject being tracked is low in luminance (ie is wearing a darker-coloured uniform). Firmware v1.1.0 is a free download; a camera serial number is required.
The same AI Servo tuneup is in v1.0.3 of the firmware for the EOS-1Ds Mark II. There is also a reduction in noise during bulb exposures, as well as a reduction in the difference in colour between the thumbnails of RAW and JPEG files when displayed in Canon's Digital Photo Professional software. Firmware v1.0.3 is a free download; a camera serial number is required.