My AF Fine tune settings for all top Nikon lenses after calibration

Started Nov 22, 2012 | Discussions thread
h2odavid
Forum MemberPosts: 69
Like?
Re: focus calibration varies with focal length of zoom lenses
In reply to GMack, Dec 11, 2012

HI Gmac,

My 70-200 actually varies by 12 focus points.  With that I suppose it would be next to impossible to get accurate focus at 2.8.  Strange how it is worse at the mid focal length, where yours gets better.  I do not see any way to set the focus adjustment.

My camera seems to be negative on all lenses, as does yours.

DOES ANYBODY ELSE IN THE FORUM HAVE EXPERIENCE WITH NIKON REPAIR  WHEN FOCUS ADJUSTMENT VARIES SO MUCH IN ZOOM LENSES?

3. 70-200 f2.8
@75mm -10

@*122mm -16
@200mm -4

GMack wrote:

h2odavid wrote:

I calibrated my Nikon lenses with my D800 and Focustune (which is easy and a joy to use). I tried 3 different focal lengths for all the zooms to see the differences. I used a tripod, mirror lockup, shutter 2 sec delay, and cable release.
THe only major differences were with my new 70-200 2.8. Do you think these results warrant a return to Nikon for this lens?
FOCUS TUNE adjustments (* lengths had the most fine tuning):

1. 24-120 f4
@ 30 mm 0
@ *85mm -3
@112mm -5

2. 14-24 f2.8
@*14mm -5
@*20mm -5
@24mm -4

3. 70-200 f2.8
@75mm -10
@200mm -4
@*122mm -16

4. 18-35 f, 3.5-4.5
@18mm -5
@23mm -5
@*26mm -7
@35mm -10

5. 10.5 mm f2.8 dx -6

6. 80-400 4.5-5.6
@400mm, -5
@*240mm, -6
@80mm, -5

Your numbers look better than mine done with FoCal.



My 70-200mm follows the same curve needing more minus at each end and less in the middle. Coincidence?

Regarding your 14-24mm f/2.8 I noticed your numbers also being better than mine too. That said, mine was worked on by Nikon new out of the box for serious back-focus (Like a block off.) and the above numbers of mine fixed by them are still worse than yours. Wanna trade?

Personally, I doubt if they can or will spend much time trying to do better on your 70-200mm. Mine has gotten a tad better and I can use around a -16 now as my general tuning number vs. the -19 above. The thing just drifts at times, but I put it through a lot of desert heat and the black barrel has gotten so hot I cannot grab it at times (My IR heat gun showed 140 once!). If I add a Nikon flash and use the red LED assist lamp (NR) in it, it may go off in some other direction as the red light seems to influence the focus tuning too.

I spoke to one of their techs once who said "his" tolerance was 5 points in the tuning values and yours differs by only 6 points. Mine is differing by 8 and maybe at some point I'll turn it over to him, but it drifts and maybe is only 5-6 points now in the mid-to-extremes now from when I did that chart above. As long as I can tune it now and get close, I'll live with it. It appears sharper than my 24-70mm f/2.8 in general so I'm hesitant to have them possibly knacker it up as they may do.

Good luck with whatever you decide. Might pay to hold off a while and see if it settles into a "more favorable set of tuning numbers" depending on your shooting conditions. If it isn't binding up in the barrels and seems to work you might have a good one if it is sharp with your values. One dealer tried to sell me a binding Sigma 70-200mm which I knew was going to be a problem sometime.

Fwiw, I'm awaiting the next release of FoCal to see how it plays out. I don't know why, but each version seems to generate data that is somewhat different from prior versions, or my gear just drifts for whatever reasons. My last few versions really was a mess with the sensor spots over prior versions (8,000+ dust spots? Really?). Still a bit of beta testing going on I guess, and I still field check the focus once I am settled into a location just because I do not trust the AF all that much. I can shoot the same eyelashes on some model and maybe 5 out of 50 is razor tack sharp for whatever reason with the same settings. Same for bird feathers. Lens spins off into some other place maybe. Dunno.

Mack

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow