was_a_guru

To use this function I've seen a technique involving using two rulers, one vertical and one at a 45 degree slope. I wonder if instead of that I could do it as the following:

1. Set back button focus mode ON
2. On a tripod, in auto focus mode, and with live view, focus manually on something with small text.
3. Then press the back button focus and see if the focus changes. (I can manually focus with back button focus enabled even though I'm in auto focus mode - 18-55 AF-P lens)
4. If focus does change then adjust the AF Fine Tune and repeat/iterate from Step 2 until no discernible change occurs

Would that work?

GoofyNewfie Loc: Kansas City

It might....try it.
I use the technique and chart available here:
http://regex.info/blog/photo-tech/focus-chart

Works very well for me.
Luckily, I haven't had to adjust anything since my D7000.

CHG_CANON Loc: the Windy City

What has prompted you to think any adjustments are needed? Your 18-55 is not a lens typically involved in such a how-to process. You probably would be better served making no changes at all ...

mharvey

There are Camera to Camera (or at least model to model) variations as well.
I have a Sigma ART 50mm f/1.4 that was fine tuned for my D810, but when I got the D850 it was so far off in back-focus that even using every bit of manual fine tuning wouldn’t fix it.
So I ran it through a Sigma Dock and reset it to factory-spec neutral and BOOM! Perfect focus in the 850.
*I had forgotten how spectacularly sharp this lens is. It just makes the Nikkor 50mm f/1.4 look poor.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Yes and no. Yes, you will fix the focus at one distance and one focal length. No, it probably won't work all that well for other focal lengths and distances.

If there is an AF accuracy issue, it's best to leave the adjustment to Nikon. The in-camera, user accessible adjustment is a single point offset. Focus behavior is rarely linear. If your lens is back focusing at 55mm and 40ft, it may be fine at 35mm and 20 ft. Adjusting for 55mm and 40ft will make it front focus at 35mm and 20ft. And so on. The techs can access multiple points of adjustment at different distances and focal lengths, both in the body and on the lens. AF Fine tune has the potential to fix one problem and create a bunch of other problems. It's best to make sure your bodies and lenses are all up to spec - this would make them all interchangeable.

TriX Loc: Raleigh, NC

Yes, and there are other similar methods that don’t require a fixture or SW such as the dot tune method: http://www.fredmiranda.com/forum/topic/1187247/0

The issue is that, depending on the body, you may not be able to accurately calibrate at multiple points within the zoom range. I’m not familiar with your Nikon body, but Canons that implement MFA typically offer two points for a zoom. One typically calibrates at the short and long end, but you can pick any two points within the range you wish. There are (strong) opinions on both sides as to whether MFA or a factory calibration is preferable (assuming the lens needs calibration at all). A UHH search on microfocus adjustment should return multiple lengthy threads on the subject. If you tend to shoot wide open at large apertures any misfocus will be more apparent and problomatical than if you typically shoot stopped down where the DOF will tend to hide any AF inaccuracies.

The Villages Loc: The Villages, Florida

And you read the whole thing? Could take days

Howard5252 Loc: New York / Florida (now)

You're dealing with minute changes, I don't think you can rely on seeing it with your eye.
In Steve Perry's e-book "Secrets to the Nikon Auto Focus System" he lists about 4 ways to use the fine tune option.
I have no financial or any other interest and I would suggest that you get his book - you WILL learn a lot.

camerapapi Loc: Miami, Fl.

In my more than 50 years photographing I NEVER had to fine tune any of my lenses. Most AF errors are operator's error.
If you are experiencing front or back focus I recommend that you take your camera and lens to a reputable camera shop and let them do the job for you. Upon inspecting the lens in camera their measurement instruments will tell them right away if there is a problem and they have better tools than yours to do the right job.
Just saying.

Howard5252 Loc: New York / Florida (now)

While your recommendation of taking the lens to a repair shop isn't bad, I would point out that your 50 years of never having to fine tune your lenses isn't really relavent. The technology didn't exist for most of that time. We bought a body and a lens and the pictures looked pretty good ... sometimes they were "Tack Sharp" (remember that expression?). Let's be honest, they were not all "Tack Sharp" and we never really thought anything was wrong. We were happy. I am not addressing obvious actual lens problems when there clearly is something wrong.
What today's technology allows is to get more of those "Tack Sharp" photos. Not all of them ... more of them. If you don't feel that the Fine Tune technology works, or that it's just an extra feature to help sell the product, that's OK. You most certainly are entitled to your opinion, but don't discourage others from trying the feature. I did, and I saw improvement in the number of really sharp photos that I was getting. All of my images are acceptable - they're not fuzzy or o/o/f, they're just not all "Tack Sharp" ... and now more of them are.

CHG_CANON Loc: the Windy City

Did you adjust your 18-55 ... ?

Howard5252 Loc: New York / Florida (now)

No. I only adjusted my prime telephotos. You and I have been down this road before. I don't insist you fine tune your lenses, allow me to fine tune mine and to tell people of my results. BTW, I don't own an 18~55.

CHG_CANON Loc: the Windy City

I'm not telling you what to do / not do. The 18-55 AS-P detail comes from the OP's post. If I was concerned about you, I'd be responding to your original post rather than this author who described a questionable approach and then mentioned a telling detail about their relative knowledge of this camera feature ... If you'd think about helping the OP more than worrying about yourself, you might have picked up on that detail ...

Rich1939 Loc: Pike County Penna.

I am of the opinion that about the only time you will see slight out of focus errors are when you are shooting wide open at close distances. Those slight errors aren't at all obvious when the lens is closed down a couple of stops. If most of your photography is something like landscape or even wide open sports action I don't feel slight errors will be evident.

mharvey

Evidently the Camera manufacturers DO see a need for lens/focal plane adjustments.
Otherwise they would not have started making
“AF-Fine Tune” a feature!