#9. "RE: Autofocus fine tuning poll!Please share your experience with autofocus fine tuning by selecting the appropriate choice below." In response to In response to 5
>Thank you all > >This is getting interesting. > >Len, if I'm reading your post correctly, you have an amazing >array of lenses. I thought I had too many with 10 of them. > >Poll is updated. > >After more testing, I have found a frustrating trend. > >A coup,e of my lenses clearly benefit from fine tune at +10 or >+15 at f1.4, but by the time they are at 2.8 or 3.2, the tune >has the opposite effect, causing back focus. > >So the tune is only good at wide apertures. This is nuts. > >Meanwhile my 105 2.8 VR is dead on without any tune. > >This lack of precision is a real concern with the D800 because >it is so revealing. >
John, that's not all my AF lenses. But yes, I have too many but I don't want to get rid of any of them. One thing I've noticed is that older lenses, and non-D/G AF lenses, are less likely to need fine tuning. One example is my AF 70-210 f4, a very old lens is dead on.
The lenses that you tune wide open and then back focus at the smaller apertures is caused by the lens design includes a focus shift. The shift almost always results in back focus. It mostly occurs with fast lenses but I found the AFS 80-200mm f2.8 has a focus shift but for me was objectionable when using a TC so I sold mine.
Another issue with the D800 is vibration caused by mirror slap. It will show up as unsharp photos at the lower shutter speeds. This may have caused some D800 owners to look at AF accuracy as the cause. I now use a higher shutter speed with the D800 than what I'm used to.
The D800 does reveal the AF focus accuracy with certain lenses but most of Nikon's bodies will show the same thing if you look closely.