#1. "RE: AF Fine Tune Question" In response to Reply # 0
AF Fine Tuning has been a very popular discussion topic here. Have you searched on Fine Tune and read the previous threads? - there is an enormous amount of information as well as debate in some recent threads.
#2. "RE: AF Fine Tune Question" In response to Reply # 0
Many (but not all) commercial targets are intended to be used at around 26x focal length. However Fine Tune testing is prone to AF system front and back focus issues which have nothing to do with the lens if you use an inappropriate target for checking. For what might be inappropriate see the guidance in your camera instruction book on what to avoid to get good results using AF or https://nikoneurope-en.custhelp.com/app/answers/detail/a_id/4585 Most reports of lens problems use targets which Nikon warn can induce front or back focus which has nothing to do with the lens Nikon are confident enough about their products to say in their fine tune notes 1/ Fine Tune is normally not required 2/ using Fine Tune is likely to interfere with infinity or minimum focus.
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.
#3. "RE: AF Fine Tune Question" In response to Reply # 0
Bay Area, US
Ignore the guidelines and test your lenses at the most used distance. I.e. there is little point to calibrate a portrait lens at infinity or a wildlife lens at close focus. I have had some cases where the subject distance had an impact on AF tuning. For some lenses it does not matter. Either way, this approach will work.
Keep in mind that most lenses should not need any AF fine tuning. Also, if done improperly you can make it worse. I would generally consider AF fine tuning only if you actually observe focus issues in your normal lens use.
#4. "RE: AF Fine Tune Question" In response to Reply # 3
The absolute worst-case scenario where a focusing error would show up is at minimum range, maximum aperture - these would result in the absolute minimal DOF for any lens, and eventually the subject would lie outside the acceptably focused planes (front or back). However, unless you regularly shoot at that range, it would be unwise to calibrate it like that, for you might find that a slight back focusing at close range might become a front focusing at medium or long ranges... IMHO.
http://egozarolho.blogspot.com 1. Good content, good aesthetics and good tecnique. On that order. 2. Light is more important than glass and pixels. 3. In the digital photography process, software is as important as gear.
#5. "RE: AF Fine Tune Question" In response to Reply # 0
Thanks to all for the responses. After some testing with many "real life" shots (not test charts) I find that I cannot get a definite setting on the 2 lenses I was trying to evaluate. At one point one setting looked good, then another, then having the fine tune off was OK. I think the best advise came from those who urged me not to fool with it. That's exactly what I've decided. I'll leave well enough alone. Bill