If you are having focus problems with the 7D try this....

Started Mar 11, 2010 | Discussions thread
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tallshorty
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If you are having focus problems with the 7D try this....
Mar 11, 2010

If your 7D is having issues with AF, try taking the same photo but use Liveview and contrast detect AF. If the image is sharper, than the 7D is either back or front focusing the lens. Use this method to calibrate:

On a tripod, turn IS off:

1) set MA to 0

2) Take 2-3 shots of any subject with good contrast outdoors in daylight from

about 10 feet away at the wide end like you normally would using centre focus point.

3) Go to Liveview and without changing your position and use contrast-detect to autofocus

4) Compare the two images. The image taken with contrast detect AF will be the sharpest you lens can achieve. If the photos you took in step 1 are softer, then your lens require microadjustment.

5) Increase or decrease the MA by 3 and repeat steps 2) to 4) and see if there is any improvement or worsening. If it improves but still softer, then you are moving the MA in the right direction and keep going, repeating the steps above. If it gets worse, then you are moving the MA in the wrong direction.

6) once you find the right MA. Repeat the above steps at the telephoto end focusing on a further subject. If you got it perfect, then there should be no difference.

This took me a while but I got my Canon 17-55mm F2.8 IS adjusted perfectly at -3

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