When using lenses with variable maximum apertures, the effective aperture is controlled according to the focal length (the zoom position), and the aperture value changes during zooming even when in manual exposure mode. This is normal operation of lens. However, in EOS REBEL T2i / EOS 550D cameras with Version 1.0.6 firmware or earlier firmware versions, Canon has confirmed that the aperture set for the lens exhibits abnormal movement when using some lenses, such as macro lenses, and is discussing improvements with the aim of incorporating them into the next version of the firmware.