Started to notice my images were not tac sharp and found out you can make fine tune adjustments. All the info on YouTube really refers to prime lenses but when it comes to zoom lenses I can't find one that advises you how to do it. If your lens is 70 to 200 do you set your lens at 70mm, place your template at 3500mm( YouTube says you use a multiplication of 50 )' or do you pick a setting at mid range. What sort of templates does anyone recommend using.