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Micro Focus Adjustment – How To

As my aging eyes require a bit of help focusing (especially for nature shots) – I have found that the preset auto focus settings are NOT always reliable as released by the manufacturer for each camera body and lens.

To save me time, I put the following information together from several sources,  the first section from: and the second section from Spyder Lenscal.

Both Canon Micro Auto Focus and Nikon AF Fine Tune allow micro focus adjustments to calibrate a camera body to a specific set of lenses.

Here is my technique:

Firstly you can test your lens to see if it is properly calibrated already and does not need any further adjustment.

  1. Download the file  pattern
  2. Using a calibrated monitor, display the above file in Photoshop at 100% (unscaled, exactly 100% on a screen and not on a print).  You should see with your eyes the Moire interference Patterns.
  3. Place the camera and lens on a tripod so that its 100% parallel to the screen (for short lenses, a small mirror lying against the screen will display the front of the lens exactly).  50 times the focal length.  For 50mm lens, 50*500=2.5m (25m for a 500mm lens, perhaps a laptop outside in this case).  The test pattern should be symmetrical
  4. Using Live View – manually focus the lens on the computer monitor test image.  Look for peek pattern visibility, not any particular pattern.
  5. Note the distance indicator on the lens carefully and the state of the image on the LiveView camera screen.
  6. Switch off LiveView and press the shutter button half way down to auto focus the lens.  The lens should not move –  the distance indicator should be identical to step 4.
  7. Reactivate LiveView – the image should be identical to step 4.

How to Calibrate the Auto Focus


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