Possible Duplicate:
What is the best way to micro-adjust a lens?

I have D7000 for some time and all of my nikon lenses were working fine. But I have bought Tamron 28-75 recently and it's autofocusing behind an object, which should be in focus.

I have experimentally set some autofocus adjustment in D7000 setting, but as I know, DOF is not just in one plane, but it's 1/3 in front of focusing distance and 2/3 behind focusing distance.

My question is:

Is there a way how to find out perfect adjustment for autofocus?

  • \$\begingroup\$ And by "possible duplicate" I mean "you'll find this very well covered at this other question". :) \$\endgroup\$
    – mattdm
    Nov 5, 2012 at 14:49

1 Answer 1


Place a ruler flat on a table, raise one end with an object to create a slope.

Erect an object that is thin and tall, a pencil maybe, at the edge of the ruler with readings, remember the position where the pencil touches the ruler(5cm for example)

Line up your camera so that :

  • The pencil is perpendicular to the lens

  • the ruler is in parallel with the lens barrel

Focus on the object, the reading (5cm) should be in focus.

Using a tripod may help.

If 4.5mm turned out to be sharp, the lens need to have its focus adjusted forward. If 5.4mm is sharp, adjust it backward.

This way you know if it is focusing in front/behind of the object, and you know roughly by how much (in mm), so you can adjust it accordingly (if the camera has such function).


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