I could use some help. I noticed my 80x400 nikkor isn't as sharp as I'd like. I purchased a spyderlenscall kit and have set it up precisely to their instructions for parallel, distance for 400mm, level, etc. When I take a picture at default, I can see it is about 1/2 inch back focusing based on the scale. I tried adjusting the AF fine tune, but, it doesn't seem to make a difference. So, I took an image at +20 and -20, they seem to be the same - not sure that is possible if AF fine tune is actually working as it should, albeit, I'm not sure. I posted the images to flickr and hoping someone with experience calibrating can help.
Thanks in advance,