I'm getting a huge number of very soft images from my 24-105L using a 40D and I'm wondering if calibration would help. I can't micro adjust on the 40D itself.

I have also yet to get around to setting it up on my tripod and doing a set of proper focus tests but in comparison to my 50mm and 10-20mm lenses, the 24-105L appears to be focusing quite badly.

I have tried combinations of focus points, focus modes, everything I can think of, yet I'm getting soft images (not all the time but a high percentage). This is with AF On of course.

Has anyone seen any improvements in sending their lens off to Canon for calibration.


2 Answers 2


Generally, sending in both camera and lens for calibration should result in more accurate AF. I would suggest that you first do some focus tests with batteries or focus charts to determine if the lens is back- or front-focusing, or if it is inconsistent AF (indicating a possible USM issue), that way you can verify the results after the lens comes back from Canon.

  • \$\begingroup\$ Someone told me of a good test. How does this sound. 1) Place the camera on a tripod and take a shot of say, a cereal box, something with text that the focus can be checked. Take the first shot on AF. 2) Next take a shot in manual using the 10x zoom function on the display. After, compare the two shots and if the first shot is out, either the lense or camera is focusing incorrectly on AF and may need calibration. I'm going to try this on Saturday and see how it goes. I'll report back... \$\endgroup\$
    – Solyad
    Nov 4, 2010 at 21:19
  • \$\begingroup\$ That's an idea, but take more than a couple of shots just to be sure. \$\endgroup\$
    – ctham
    Nov 4, 2010 at 23:52
  • \$\begingroup\$ Search around, there are questions about focus tests here. The test you describe isn't super reliable. \$\endgroup\$
    – Reid
    Nov 5, 2010 at 0:15

There are other types of calibration besides focus calibration - one of the elements could be out of alignment causing softness under certain conditions. This could be the result of a manufacturing defect or damage.

This happened to me when I dropped one of my lenses, I sent it to Fixation in London (an official Canon repair centre) and that solved the problem. I don't know where your based but Canon could probably advise you of where to send it if it's not an AF problem.

  • \$\begingroup\$ I'm based in Ireland, so not sure where in Ireland I can send it. It may need to go to London... \$\endgroup\$
    – Solyad
    Nov 4, 2010 at 21:23
  • \$\begingroup\$ There ought to be a Canon certified repair centre (probably many) in Ireland. If you contact Canon customer services they should be able to advise you. \$\endgroup\$
    – Matt Grum
    Nov 4, 2010 at 23:54
  • \$\begingroup\$ I'll look into that, I only know the Sigma one in Cork so wasn't sure if there was a Canon one also. \$\endgroup\$
    – Solyad
    Nov 5, 2010 at 8:24

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