How To Get Your 450D AF Fixed

Started Apr 10, 2009 | Discussions thread
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WilbaW Forum Pro • Posts: 11,422
How To Get Your 450D AF Fixed

When I became aware of discrepancies between the focus achieved by my 450D's phase detect and contrast detect autofocus modes, I verified that the the system was consistently not meeting Canon's specification. It was doing that with my 50/1.8 and 18-55 under certain conditions, e.g. near the minimum focal distance at wide apertures.

Here's one way I could show the error -

I called Canon in Sydney, they said fine, just send everything. I asked but the customer service guy wouldn't put me through to a technician or supervisor. I sent the camera body, my 50/1.8, 18-55, and 55-250, with a detailed explanation and a bunch of test shots on an SD card.

About four weeks later it came back with service notes like, "Extensively checked and tested, unit found to be working within manufacturer's specification. No fault found." The performance was the same as before, so I assume no adjustments were made.

When I called again, I was put through to a "customer consultant", who confessed he didn't have the technical knowledge to follow the story, but he was very willing to listen and help. I sent him the same files that went with the camera the first time, and after consulting with a "senior technician" he asked me to send in the camera again.

The consultant kept in touch with me throughout the four weeks the camera was away. He let me know when the technician confirmed that the system was not performing correctly.

Yesterday the camera came back. Now it does this -

The difference between the two methods is of the same order as the difference between shots using the same method. It doesn't get any better than that, and it seems to be spot on now with all of my lenses under all conditions.

The service notes say, "Best focusing has been performed, cleaned and tested all functions." So I don't know what has been adjusted or in what way.

The specific questions I asked, about the Canon specification and my camera's performance, were not answered, but they sent me some images of the focus achieved on their test rig. For instance, 50/1.8 @ f/4.5 -

So here are some observations. Canon Australia service staff are unfailingly polite and willing to help to the extent that their policies and procedures allow. They won't let you bug the technicians, and that's fair enough I guess.

When you send in a camera for "auto focus issues", it seems that a junior technician will test it against the specification, and may find that it passes those tests.

When you call to enquire about a warranty job that didn't fix your problem, you can get through to someone beyond the call centre. That person might not understand the technical issues, but they will consult with those who do, and will work with you to get it fixed.

The key seems to be to get past the first level of support. Others have reported that they weren't able to get a fix until they spoke to someone on the inside. The problem is, you will probably have to go through at least one cycle of sending the camera in before you can get to the second level.

Your camera will come back with everything reset to factory defaults, including any picture styles you have created. So before you send one in, make a note of your settings. My "My Menu" settings weren't affected.

My advice to anyone who thinks they have AF problems goes like this. Make sure you can repeatably show the problem as a difference between phase detect and contrast detect autofocus, under controlled conditions. Make sure that the difference puts the subject clearly outside the DOF at normal viewing sizes and distances. Use a wide aperture lens (f/2.8 or better if you can). Send your camera to Canon for calibration, but expect it to come back unchanged. Call Canon again, explain to the call centre guy that a warranty job didn't solve your problem, and ask to be put through to someone who can disuss it. Expect to be without your camera for many painful weeks, depending on how busy is your service centre.

For me, it was worth it.

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