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EF 24-70 f2.8 L USM lens not focusing (from 24-50)!


I have an expensive Canon EF 24-70 f2.8 L USM lens that I bought new years ago. Yesterday, during an important assignment, my 5d MarkIII would not fire when lens was at 24mm. The camera would not fire from 24 to about 50mm range. After 50mm, it would fire. Many of the images from that camera proved useless because they were very soft. To be sure, I switched my 24-70 with another 5D Mark III body that had my Canon 70-200 f2.8 L USM lens and the results were the same therefore, the problem is with the 24-70 lens. In 4 days, I have more important assignments shooting a college graduation. Besides sending the lens into Canon repair, is there a FIX that I can do or is it possibly a firmware issue?



What aperture does the camera report when the lens isn't working. Also what is the full name of the lens that lens has 2 versions of it.


Current Gear: EOS 5D Mark IV, EF F/2.8 Trinity, EF 50mm F/1.8 STM, EF 85mm F/1.8 USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D


I have two thoughts

  1. Canon may not be able to service your EF 24-70mm f/2.8L USM as it is beyond service life, unless its the EF 24-70mm f/2.8L II USM model.
  2. Rent an EF 24-70mm f/2.8L II USM to cover the assignments this week.

As far as I am aware there were no user installable firmware updates for the EF 24-70mm f/2.8L USM or EF 24-70mm f/2.8L II USM lenses.

EOS specialist trainer, photographer and author
-- Note: my spell checker is set for EN-GB, not EN-US --


Thank you all for your interest and replies.  I YouTubed my issue and found a photographer in England that was experiencing similar issue.  Instead of shipping the lens off for repair, he decided that he would take a crack at it by removing the lens from the body and doing a quick inspection.  He found that several screws were slightly loose and so he tightened them and gave the sensor a wipe with an alcohol pad.  I tried his method and it worked!!!!! 

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