EOS Rebel T2i / 550D Firmware Update Version 1.0.8

"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).
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)."

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