Canon EF 40mm f/2.8 STM Lens Firmware Update ver. 1.2.0

Canon EF 40mm

Canon has issued a firmware update for the EF 40mm f/2.8 STM lens.

Firmware Version 1.2.0 addresses the following phenomenon.

1. If pressure is applied to the lens barrel while the lens is mounted to the camera (pressure can be applied even while attaching the lens cap or while carrying the camera with the lens attached in a bag), the autofocusing function of the lens may stop working.

Note that only the following cameras can be used to install the update:

  • Canon 1D X
  • Canon 5D Mark III
  • Canon Rebel T4i / 650D

If you do not have one of these cameras, you can send the lens into a Canon service center to have the update applied.  Canon USA customers can contact the Canon Customer Support Center at 1-800-652-2666.

You can download the update via Canon’s website.



  1. kdsand says

    Oh poo.
    So does that mean the newest bodies are able to send the firmware into the lenses. I assume it does. Hmm.

    Bummer having a 60D I gotta send it in. :-(

  2. Alex B says

    Same here. Although I haven’t experienced the issue, so until I think I will hold off…or find someone with a newer camera.

  3. kdsand says

    I’ve had it freeze up once. Not the most terrible issue to deal with though it would be nice if it was fixed. I like using the lens when staying inconspicuous like street photography so in those circumstances I might not notice it froze up & miss my shots.

    Just a bit of a pain in the butt ox :-) .

    It is cool to know the new bodies (even rebels ) are now including the ability to update lenses.