This is one in a series of posts on the Nikon Z7. You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just look for “Nikon Z6/7”.
In the previous post I started out testing the Z7 for autofocusing accuracy in various focusing modes, but discovered my testing wasn’t valid because I was assuming that there was a CDAF trim step after the cameras PDAF focusing, and it appeared that either that wasn’t happening at all, or it wasn’t very effective.
That caused me to think about the PDAF fine-tuning function in the Z7. I’d figured that it wouldn’t affect accuracy, just speed, in that it would allow the hare-like PDAF phase of the autofocusing to get closer to the correct location so that the tortoise-equivalent CDAF phase would go faster.
But what if there isn’t a CDAF phase, at least with adapted lenses? Then the PDAF fine tuning would affect accuracy, not speed.
I put the 105 mm f/1.4 lens on a Z7, set it up a bit under three meters from my checkerboard ramp, and made 16 exposures in AF-S Single mode with AF fine tuning set to -20, -10, 0, +10, and +20. I racked the lens towards the far on the odd exposures, and in the near direction on the odd ones. I analyzed all the data, and here’s what I saw:
AF fine-tuning does affect accuracy. It affects it in just about the same way as in the D850, with each step changing the image-field focal plane by about 4 micrometers. In the above chart, negative numbers on the y-axis mean object-field focus shift away from the camera. This is the opposite of the usual way I do things. I apologize for the inconsistency.
In Pinpoint mode, which uses CDAF instead of PDAF, the results are similar except for lower scatter:
It’s going to take a while to digest the implications of this.
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Aug 08, 2017 Do you have a Nikon camera that features Auto AF Fine Tune? If so, then this video is just what you need to get the most from it! When Auto AF Fine Tune first came it, it was pretty exciting – In fact, I think we all had visions of never going through a tedious lens.
For a Nikon DSLR, go to the menu with spanner icon and in there at the bottom, you have the Af Fine-Tune Menu. Go in there and then turn on the AF-Fine-Tune. Auto AF fine-tune failed.
Nov 16, 2017 My current setup is a Nikon D7200 and the Nikon AF-S 80-400MM F/4.5-5.6G ED VR. Lately I am not happy with the overall images and would like to know if there is a specific way for me to try and use the Auto Fine tune feature to dial in the gear better. 1 Ready the camera. Mount the camera on a tripod and aim the camera at a flat, high-contrast subject parallel to the camera focal plane. Note that auto AF fine-tuning works best at maximum aperture and may not function in dark surroundings.
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ario arioldi Offline • Upload & Sell: Off
p.1 #1 · p.1 #1 · Z7 AF Fine Tune
Anybody knows what is the purpose and how to use it on this mirrorless camera which is supposed to use hybrid AF? I have not found anything useful on the user manual.
Oct 07, 2018 at 03:02 PM
pwschladen Offline • • • • Upload & Sell: On
p.1 #2 · p.1 #2 · Z7 AF Fine Tune
I think someone else posted this on another thread: https://blog.reikanfocal.com/2018/10/the-new-nikon-z7-investigating-with-reikan-focal/
Oct 07, 2018 at 03:12 PM
ario arioldi Offline • Upload & Sell: Off
p.1 #3 · p.1 #3 · Z7 AF Fine Tune
Thank you.
Oct 07, 2018 at 03:30 PM
charles.K Offline • • • • • • Upload & Sell: Off
p.1 #4 · p.1 #4 · Z7 AF Fine Tune
It is interesting as we assume PDAF to be perfect but it is not according to the article by Reikan Focal
Oct 07, 2018 at 09:44 PM
rick2906 Offline • • • • Upload & Sell: Off
p.1 #5 · p.1 #5 · Z7 AF Fine Tune
Well that sucks! I was hoping for perfection since it is focusing directly on the sensor. It is one of the big advantage for mirrorless imo.
Oct 07, 2018 at 10:38 PM
sakete Offline • Upload & Sell: Off
p.1 #6 · p.1 #6 · Z7 AF Fine Tune
rick2906 wrote: Well that sucks! I was hoping for perfection since it is focusing directly on the sensor. It is one of the big advantage for mirrorless imo. Well, from reading that article, it's a good thing that Nikon did include it. Eventually lens tolerances get slightly looser with wear and tear, and then you'll need to make an AF adjustment anyway. For example, the camera tells the lens to move 5 focus units in some direction, but instead it only moves 4.5 (the lens communicates to the camera that it moved 5 focus units, but in actuality it was only 4.5 units). Then you can add an AF adjustment so that what the camera tells the lens to do, and what the lens actually does, will line up.
Oct 07, 2018 at 11:07 PM
rick2906 Offline • • • • Upload & Sell: Off
p.1 #7 · p.1 #7 · Z7 AF Fine Tune
sakete wrote: Well, from reading that article, it's a good thing that Nikon did include it. Eventually lens tolerances get slightly looser with wear and tear, and then you'll need to make an AF adjustment anyway. For example, the camera tells the lens to move 5 focus units in some direction, but instead it only moves 4.5 (the lens communicates to the camera that it moved 5 focus units, but in actuality it was only 4.5 units). Then you can add an AF adjustment so that what the camera tells the lens to do, and what the lens actually does, will line..Show more → Yes, I Know. It will be minor adjustment compare to dslr. It is bettter to have the abilty to make adjustment then not having the option. Edited on Oct 08, 2018 at 03:33 AM · View previous versions
Oct 08, 2018 at 01:18 AM
Kubicide Offline • • Upload & Sell: On
p.1 #8 · p.1 #8 · Z7 AF Fine Tune
Actually, the article is not correct and simply the author's incorrect assumption. We don't know why Nikon included an adjustment - there shouldn't need to be one as the mechanical flange back / backfocus is set unless damaged. The focus adjustment was needed in DSLRs because of the separate AF sensor (vs. the focal plane sensor) which could be off due to the mirror or other error tolerances. But in a mirrorless there should be absolutely no reason for AF adjustment. None.
Oct 08, 2018 at 03:01 AM
charles.K Offline • • • • • • Upload & Sell: Off
p.1 #9 · p.1 #9 · Z7 AF Fine Tune
Having the fine AF adjustment is great to have. Even if you have no internal tolerance errors you may decide to move forward or back the DOF to suit your shooting.
Oct 08, 2018 at 03:34 AM
Photozack81 Offline • • • Upload & Sell: Off
p.1 #10 · p.1 #10 · Z7 AF Fine Tune
The old adage 'It's better to have it and not need it than need it and not have it' applies here.
Oct 08, 2018 at 06:02 AM
Thern Offline • • • Upload & Sell: Off
p.1 #11 · p.1 #11 · Z7 AF Fine Tune
charles.K wrote: It is interesting as we assume PDAF to be perfect but it is not according to the article by Reikan Focal Well Reikan makes a living from their calibration software don't they? -1 really? WOW! If I test my lenses in the field and compare the results with the Lenscal I find the results pretty on par with each other. -1 or +1 doesn't bother me at all that is imo perfection in the real world. (Who knows! this Reikan result may be the error of their own software..) Nonetheless If you're shooting AF-C I can't see how worn AF can influence AF acquisition, the camera will keep telling the lens to move to the required focus. With AF-S this might happen to be true however I do have a hard time to believe this. Reikan told us back in the days automated AF finetune to be inaccurate, well IF you do this the correct way and compare the results with manual finetune you won't find a large enough difference to be able to tell which value holds the absolute truth and nothing but the truth. I bought their Pro software, used it and decided it couldn't do better than my old lenscal like a lot of my friends did too. Nice software for some loving to look at diagramms and such but no magic involved. Imo the worst prop a lens may have is AF inconsistency if they could cure that now that would be magical!
Oct 08, 2018 at 06:55 AM
charles.K Offline • • • • • • Upload & Sell: Off
p.1 #12 · p.1 #12 · Z7 AF Fine Tune
Thern wrote: Well Reikan makes a living from their calibration software don't they? -1 really? WOW! If I test my lenses in the field and compare the results with the Lenscal I find the results pretty on par with each other. -1 or +1 doesn't bother me at all that is imo perfection in the real world. (Who knows! this Reikan result may be the error of their own software..) Nonetheless If you're shooting AF-C I can't see how worn AF can influence AF acquisition, the camera will keep telling the lens to move to the required focus. With AF-S this might happen to be true however..Show more → It is fun to check but I see a +1 or +2 used for AF-C face recognition for close to medium portraits depending on where you prefer to nail the AF. Some prefer the iris some the eye lashes. With 105E or 58G the DOF is so narrow it is nice to fine tune even with the Z7 I do all the time with the D850. I use Reikan and sometimes but mostly my Len Align target for simplicity. Both work great and just another technique that gives a statistical spread.
Oct 08, 2018 at 07:36 AM
Thern Offline • • • Upload & Sell: Off
p.1 #13 · p.1 #13 · Z7 AF Fine Tune
I can certainly see what you're saying Charles, just asking how do you know your model wasn't blinking or breathing the moment you initiated AF acquisition? I'm sure the room for 'usererror' and AF inconsistency is playing a much more larger role in this respect than AF accuracy (frontfocussing one point like Reikan states) Well you own the Z7 would be nice to test this on a modells eye from a tripod NOT instructing the modell to hold her breath and see the results of say 10 similar single shots every time initiating AF acquisition inbetween. The D850 or any other DSLR needs often calibration but that's the concept of a sensor separated AFmodule. (even then you'll find this) Even shooting a static object from a solid tripod with remote release will show AF inconsistency. (offcourse depending on the very lens) /edit I'm not familiar with AF-C face detection but it sounds like something I wouldn't choose for portraiture. I stand corrected if I'm wrong but is this mode capable to distinguish eye and lashes? or does it 'look' for the face then the 'eye-region' and focusses on that? Edited on Oct 08, 2018 at 08:43 AM · View previous versions
Oct 08, 2018 at 08:33 AM
charles.K Offline • • • • • • Upload & Sell: Off
p.1 #14 · p.1 #14 · Z7 AF Fine Tune
Thern wrote: I can certainly see what you're saying Charles, just asking how do you know your model wasn't blinking or breathing the moment you initiated AF acquisition? I'm sure the room for 'usererror' and AF inconsistency is playing a much more larger role in this respect than AF accuracy. Well you own the Z7 would be nice to test this on a modells eye from a tripod NOT instructing the modell to hold her breath and see the results of say 10 similar single shots every time initiating AF acquisition inbetween. The D850 or any other DSLR needs often calibration but that's the concept..Show more → There are definitive possible errors but with a lens like the 105E it is accurate I do adjust the AF fine tune often to suit with the D850. I still have yet to pick up my Z7 but with a lens like the 58G it is well worthwhile to test out the different settings as the lens is quirkish and maybe pushing the AF back marginally will work better for some portraits. All interesting stuff For portraits I use AF-C exclusively this allows for any fine movement in either myself or the subject.
Oct 08, 2018 at 08:39 AM
Thern Offline • • • Upload & Sell: Off
p.1 #15 · p.1 #15 · Z7 AF Fine Tune
Well nothing wrong about checking things that's for sure and being able to adjust for one's own needs even more so
Oct 08, 2018 at 08:47 AM
ilkka_nissila Offline • • • Upload & Sell: Off
p.1 #16 · p.1 #16 · Z7 AF Fine Tune
sakete wrote: Well, from reading that article, it's a good thing that Nikon did include it. Eventually lens tolerances get slightly looser with wear and tear, and then you'll need to make an AF adjustment anyway. For example, the camera tells the lens to move 5 focus units in some direction, but instead it only moves 4.5 (the lens communicates to the camera that it moved 5 focus units, but in actuality it was only 4.5 units). Then you can add an AF adjustment so that what the camera tells the lens to do, and what the lens actually does, will line..Show more → But in continuous focusing, getting the focus where it need to be does not rely entirely on the motor moving the focus exactly where the camera hopes, but it's always just an approximation and once the focusing operation has been carried out the focus is checked again and iteratively adjusted continuously while focusing is on. Focus fine tune would not likely be able to solve such a problem that is related to the lens motor not carrying the instructions accurately, since it introduces a systematic bias into the system (and the motor error is likely relative to the movement required). Fine tune can be used for correcting the different paths of light that contribute to the image captured by the main sensor and the light captured by the separate AF sensor module in a DSLR. In a mirrorless camera, the on-sensor phase-detect sensors also may have different family of angles of accepted light that contribute to the result and this could cause the need for a small fine tune adjustment in some cases. But it is likely much smaller than in a DSLR.
Oct 08, 2018 at 09:07 AM
Dj R Offline • • • • Upload & Sell: On
p.1 #17 · p.1 #17 · Z7 AF Fine Tune
I would fine tune my lenses monthly when I had nikon dslr. If a lens was +15 or more, I would get rid of it. So much time spent! I went primarily mirrorless in november 2017, and while yes, there is a setting for it on the sonys, I have yet to see a need to fine tune. I mostly shoot 1.4 glass, and an A7rIII is my primary (42.4mp) I would expect similar results from nikon! here's hoping!
Oct 08, 2018 at 06:41 PM
Nikon Z7 Auto Af Fine Tune
brafman Offline • • Upload & Sell: Off
p.1 #18 · p.1 #18 · Z7 AF Fine Tune
The fine tune in the sony menus is not for ordinary FE lenses. Its for adapting DSLR lenses using a certain sony adapter; I forget the details.
Oct 09, 2018 at 08:25 PM
charles.K Offline • • • • • • Upload & Sell: Off
p.1 #19 · p.1 #19 · Z7 AF Fine Tune
brafman wrote: The fine tune in the sony menus is not for ordinary FE lenses. Its for adapting DSLR lenses using a certain sony adapter; I forget the details. Correct. If you are using LA-EA4 you still require fine AF adjustments with lenses like the ZA 135/1.8
Oct 09, 2018 at 09:28 PM
davewolfs Offline • • • • Upload & Sell: Off
p.1 #20 · p.1 #20 · Z7 AF Fine Tune
Why does Nikon have this but Sony doesn’t. It kind of doesn’t make sense to me. If the Camera tells a lens to move N and in doing so it is still not in focus - shouldn’t the camera be able to detect the delta and suggest the adjustment. Is this a crappy implementation on Nikons part?
