Sorry if I'm beating a dead horse, but I must ask. Does the AF Fine tune matter with Zooms since all the focal lengths might vary the front/back focus issues with some users? I'm looking at Jeffrey Friedl's blog about the front/back focus issues, and it says to keep the camera square with the chart on a flat surface, so is the camera at a certain angle looking at the chart? I'll be testing my 28-75 and at 28mm, there is a lot of DoF, so is there a point testing at 28? I guess testing from 50 -75 will be better. Thanks for the help! Link to Jeffry Friedl's blog. http://regex.info/blog/photo-tech/focus-chart The lens align looks nifty, but a little expensive.