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Old January 21st, 2008, 02:34 PM
Wil Andrews Wil Andrews is offline
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Join Date: Jan 2008
Posts: 3

Here's some very good news. This test with a 1MIII with the focus fix from Canon shows tack sharp auto focus with the three lenses I have with me (16-35L, 24-105L, and 70-200L). Earlier tests with other means showed some adjustment needed before the camera was sent in for repair.

Conduction the test as described produced such fantastic results that I felt a more rigorous test should be done. I devised a two step test:

Step 1: Do exactly what has been described here.

Step 2: Do not move camera.

2.1: While not in Live View, but in Auto Focus mode, manually rotate focus ring to de-focus the lens.

2.3: Press shutter half way down to actuate auto focus.

2.4 Without moving anything, enter Live View.

If the moire lines are still there, the auto focus returned the lens to tack sharp focus.

This part of the test should only be done after the user is satisfied with any adjustments made.

I added this test to see if the lens motor and or auto focus circuit has any hysteresis (slop in returning to same point). I am delighted to report that all works fine.

The only question I have is that Canon recomends that the tests be made at a "distance similar to actual subject matter you shoot . . ." But the argument against that is that Canon doesn't and can't do it that way themselves in their service center.

Time will tell how all this works out.

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