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EF 40mm f/2.8 STM Support
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EF40mm f/2.8 STM Firmware Version 1.2.0 [Windows]

Content Id: 0400063302



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.

Firmware Version 1.2.0 is for lenses with Firmware Version 1.1.0. If the lens' firmware is already Version 1.2.0, it is not necessary to update the firmware.

The lenses with the following serial numbers are equipped with Firmware Version 1.1.0:

The third digit in the serial number is either 0, 1, or 2 (xx0xxxxxxx, xx1xxxxxxx, or xx2xxxxxxx).

Lenses with serial numbers other than those listed above are equipped with Firmware Version 1.2.0.

- If an extension tube, or cables, such as USB cables, are attached to the camera, the firmware may not be successfully updated, so make sure that you detach the extension tube, and/or cables before updating the firmware.
- A supported camera* is required for the firmware update.

Cameras that can be used for the firmware update:
Canon EOS-1D X (*1), Canon EOS 5D Mark III (*1,*2), or Canon EOS Kiss X6i/REBEL T4i/650D

*1 If the "Battery Info." on the menu screen is checked right before performing the firmware update, the update operation may fail. If the battery information is checked, turn off and on the power before performing the firmware update. If the update fails, please remove and reinsert the battery then perform the firmware update again.

*2 The firmware update operation may fail if updating the firmware under any of the following conditions:
a) The camera's (EOS 5D Mark III) firmware version is Version 1.1.2 or earlier.
Update the camera's firmware to Version 1.1.3 or later first, before performing the lens firmware update.
b) The battery information (EOS 5D Mark III) is registered in the camera
Delete all the registered information first, turn off and on the power, and then perform firmware update.

If the firmware update operation fails, remove the battery and lens. Insert just the battery into the camera (without attaching the lens). Power on the camera and if you are using an EOS 5D Mark III, confirm that the firmware version of the camera is 1.1.3 or later and there is no battery information registered in the camera. After confirming the above two conditions, attach the lens and perform the firmware update again.

Customers who do not own any of the cameras listed above, but wish to have the firmware of their lenses updated, are asked to contact our service centers.

Q&A Section:
Preparations for the Firmware Update:

After the downloaded compressed file (.zip) is extracted, a firmware folder is created.

*Extracting the downloaded file: Right-click the zip file, and then select Extract All to extract the file. The extracted folder contains the firmware (file name: EF005120.LFU / file size: 1,441,844 bytes) and instructions on the firmware update procedures (a PDF file in five languages: Japanese, English, French, Spanish, and Simplified Chinese).

Before starting the firmware update operations, please confirm the contents of the download and carefully read through the firmware update procedures.

File information

File Name :
File Type : FA
File Size : 1481085KB