I came across this post on PetaPixel a while back, but I sought it out again last night because my Tamron 17-50 arrived in the mail and I suspected it might need some AF adjustments done.
http://petapixel.com/2013/03/12/ghettoca-a-diy-lens-calibration-tool-for-mic...enabled-dslrs/
So I made the chart last night. It took all of 20 minutes. I used it today (at work, to kill time) and it was very helpful in letting me see how my Tamron was performing. The numbers on the ruler don't necessarily correspond to any sort of AF adjustment measurement (I think) but nevertheless the lines help you see what is and isn't in focus, and help you track the effect your adjustments are having.
I thought it might come in handy here since a lot of posts pop up relating to focusing issues.
And here's a shot of the chart in action:
https://www.dropbox.com/s/bq1zsdq4ztfqoa2/20130410_123404.jpg
Note: If you don't have a tripod/gorillapod handy to raise the level of your camera, you can just use a stack of magazines or books to raise the level of the chart and camera until they are even with each other.
Last edited by EarlVonTapia; 04-10-2013 at 01:12 PM.