Canon has released firmware updates for both the Canon EOS-1D Mark IV DSLR and the Rebel T2i/550D.
Both the updates are labelled V1.0.8 and fix a few bugs in the cameras. The Canon T2i/550D's firmware update fixes a problem with the aperture moving unexpectedly whilst in manual exposure mode on some Canon lenses.
Supplemental Information: This phenomenon involves the aperture of the lens moving unexpectedly when the focusing ring moves (during focusing). Please note that aperture values also change when operating the zoom ring of a zoom lens that has variable maximum aperture values; however, this is a normal operation because the camera controls aperture values properly depending on the focal length (zoom position).
Full details of the Canon T2i firmware update can be found here.
The details for the Canon EOS-1D Mark IV firmware are listed below. The full text with instructions can be found here.
Firmware Version 1.0.8 incorporates the following fixes.
1. Fixes a phenomenon in which the set aperture moves unexpectedly when shooting movies in manual exposure mode using some Canon lenses (such as macro lenses).
2. Corrects misspellings in the French and Spanish menus for applicable products.The Version 1.0.8 firmware is for cameras with firmware up to Version 1.0.6. If the camera's firmware is already Version 1.0.8, it is not necessary to update the firmware. Note that cameras with the Version 1.0.8 firmware cannot be downgraded to a previous firmware version (such as Version 1.0.6).
Before downloading the firmware update, please be sure to read the entire contents of this page.
Via: DPReview