It seems most are conducting the tests as the manual states for FocusTune. However, I am still at a loss of how to handle my 16-35,24-70, 70-200mm lenses and for that matter my Sigma 50-500mm as I only have two choices which are
a) choose the focal length which is most commonly used, or.... b) test the lens at e.g. widest, then 25%, 50%, 75% then 100% zoom.
I have tried the 24-70mm as per a) above and the b) option. With the b) option the FocusTune readings are so far apart between focal lengths. On the basis that the final AF-fine tune value is the only value for that lens that can be set, then it makes it a ridiculous exercise!
For the life of me I don't see how a zoom lens can be accurately catered for across its range unless it's used at a set focal length, then it just becomes a prime!