focus calibrate my lens how far do I have to be away from the target?

[Corey Hayes]

Hey guys simple question I got my self a Lens Cal but I am not sure how far back I need to stand for the 500mm and 700mm.
And this may sound dumb but on the lens cal there are two targets the large one and a smaller one next to the ruler, what one should I aim at?

thanks

[Doug Schurman]

Typical recommendation for a long telephoto is about 25x the focal length which is 2.5 meters per 100mm of focal length. Another option is to use a distance that you typically are from your subject.

You focus on the larger target that is parallel to you sensor.

Check out Artie's tutorial
http://www.birdphotographers.net/forums/content.php/161-The-Lens-Align-Mk-II-the-Non-tethered-Micro-adjusting-Tutorial-by-Arthur-Morris

[Roger Clark]

I test in the field at the same distance as my subject, and thus at the temperature at that time. The MA is temperature dependent. See:

http://www.clarkvision.com/articles/microadjustment/

Roger