Why you should AF Fine Tune Nikkor Lenses – Reikan FoCal

Since the introduction of the Nikon D3 way back in 2007, middle to high-end Nikon camera owners have been able to adjust the focus system of their camera to work better with each lens.Why you should calibrate Nikon Nikkor lenses with Reikan FoCal

Reikan FoCal takes the guesswork out of this adjustment by automating the process and using advanced computer analysis to determine the best adjustment for your camera and lens. Over the past 5 years, FoCal users have been uploading their results to our database, and we process this information and feed it back to let them compare how their camera and lens compares with everyone else.

The last post looked at the detail about the real world need for AF Microadjustment on Canon cameras with Canon EF lenses, so I wanted to now take the same look at Nikon cameras with Nikkor lenses to see if things look about the same.

Another Spoiler Alert!

Not surprisingly, it turns out the results for Nikon lenses follow pretty much the same pattern as Canon lenses, albeit with a little bit of a stronger conclusion:

For most Nikkor lenses, there’s a 1 in 2 chance you’ll get a significant improvement in image quality by adjusting your autofocus with Reikan FoCal.

But don’t just take our word for it.  I’ve shown below the information for each of the lenses we have data for.

Nikkor Lenses

The Nikon F Mount was introduced in 1959, and since then some 400 Nikkor lenses have been produced.  Although older lenses are still compatible with new cameras, there are many more users of more modern Nikkor lenses on FoCal-supported cameras, so our database contains a little over 60 different Nikkor lenses with high quality data associated.

As with the similar Canon post, I’m going to use the results to show how likely it is that any particular lens will benefit from calibration. I want to try and answer the question:

“When I take that shiny new lens out of the box, what are the chances that I’m going to get the best from it without any adjustment?”

How likely is is that a lens needs no adjustment at all?

We’ve taken all the data and worked out the percentage of each lens type that required no calibration at all (i.e. the AF Fine Tune result from FoCal was 0). Here’s that data shown for all the Nikkor lenses (ordered from most-likely to least-likely to be just perfect out the box):

Reikan FoCal - Nikon Nikkor Lenses requiring very little calibration
image-17165

(Note: click on the chart to see a large view)

Let’s start at the very left of the chart. The Nikkor 500mm f/4 lens has a value of around 13%… so what does that mean? It means that – on average – if you had 7 of these lenses on the bench in front of you, 6 out of 7 would produce sharper photos if you ran them through FoCal. Only 1 of the 7 (13%) would not need any calibration. And that’s for the best on the list!

Move to the fifth lens on the chart (to the 10-24mm), and you’re down to less than 10%, i.e. more than 9 out of 10 lenses would benefit from calibration!

And at the far right, the last lens types (the 400mm f/2.8) could do with calibration for every single copy of this lens!

Which lenses need just a little adjustment?

To be honest, we’ve gone for a pretty stringent requirement above of needing a calibration result of zero.  In reality, you’ll usually not notice much of a difference with an adjustment of 2 AF Fine Tune points, so let’s have a look at what happens if you include all the results that needed just a small amount of calibration (-2 to +2 AF Fine Tune result):

Reikan FoCal - Nikon Nikkor Lenses requiring a small amount of calibration
image-17166

Things are looking a bit better here…

Again, starting at the far left, this time it’s the Nikkor 18-35mm f/3.5-4.5 that’s best, and our number has jumped to around 50%. So now 1 in 2 of those lenses won’t need an AF Fine Tune of more than +/-2 points.  But conversely, we’re saying that 3 or more AF Fine Tune points starts to mean a significant image quality improvement, and that means that the other half of all Nikkor 18-35mm lenses (the best in this list) would benefit from calibration.

Let’s think about that…  over half of all tested Nikkor lenses would see a significant benefit from calibration.

For the half of the lenses on the right side of the chart, you’ve got more than a 80% chance that you’ll see a significant improvement using FoCal.

What does this adjustment look like?

I keep mentioning tiny, small and large calibration differences, but what do these actually look like?  The images below show the difference between a well calibrated Nikkor lens, and an offset of 2 AF Fine Tune points (barely any noticeable difference), a 10 point error (significantly blurred), and a 20 point error (hugely blurred):

Reikan FoCal - example of AF Fine Tune error images for Nikkor lenses
image-17167

The yellow chart above (Percentage requiring very little calibration) shows the percentage of lenses that fall somewhere between Calibrated and 2 point error.  The remaining lenses – that’s more than 1 in 2 lenses for 80% of the different lens types – are somewhere between 2 point error and 20 point error!

Another thing worth noting is that autofocus isn’t perfect and can focus on slightly different positions with each shot.  By calibrating with FoCal, you not only improve the absolute image quality you can achieve, but you also improve the likelihood of achieving a better quality image.

The Scary End!

Finally, let’s take a look at the scary end of the figures – the lenses which needed a huge calibration (more than 10 AF Fine Tune units):

Reikan FoCal - Nikon Nikkor Lenses requiring a huge amount of calibration
image-17168

This time, the left side of the chart is a bad place to be. If you had 10 copies of the Nikkor 80-200mm lens on your desk, typically 6 out of 10 of them would get a massive improvement (more than 10 AF Fine Tune points) after calibration with FoCal!

The number does drop, but for majority of lenses you’ve still got a greater than 1 in 5 chance that you’ll need a really big adjustment (more than 10 AF Fine Tune units) to get the best from the lens.  And to put that in context, all of those lenses will be producing results between the 10 point error and 20 point error images above!

Conclusion

There’s a pretty simple conclusion here: you really should run every lens you have through FoCal’s Fully Automatic Calibration!  For Nikon, this applies even more so than our findings with Canon EF lenses.

For most Nikkor lenses there’s a high chance you’ll get a noticeable improvement (3 or more AF Fine Tune points) in image quality after calibration, and for around 1 in 5 you’ll get a massive improvement (more than 10 AF Fine Tune points).

FoCal takes all the guesswork out of adjusting your lenses, so for the sake of a few minutes with each lens it really is worth it to get the best from your kit.

Take a more detailed look at FoCal on the website.

26 comments on “Why you should AF Fine Tune Nikkor Lenses – Reikan FoCal

    • Hi Steve,

      Thank you for your interest in Reikan FoCal.

      FoCal works really well with longer lenses, if you shoot wide open or close to wide open you will more often than not see a large improvement in focusing especially with longer lenses (due to shallow depth of field). Note with lenses over 400mm length FoCal Pro is required, see also Which version of Reikan FoCal should I buy?

      Best Regards,
      Dave

      Reply
  • as I have a number of lens if I calibrate each lens and let’s say they have all differ value.
    do I have to run calibrate each time or just remember values and put them in the camera

    Reply
    • Hi George,

      Thank you for your interest in Reikan FoCal.

      Once a calibration is made for a camera/lens combination the camera stores that calibration result internally. When the lens is re-attached the camera recognises the lens and applies the previously stored calibration setting. There’s some good videos that give lots of background info, see Are there any FoCal calibration videos I can watch?

      Best Regards,
      Dave

      Reply
    • Hi Robert,

      Thank you for your interest in FoCal.

      Sorry to say at this time FoCal works only with Canon and Nikon dSLR which support AF Microadjustment / AF Fine Tune. See also FAQ entry Is my camera / lens supported by FoCal? for some background 🙂

      I won’t say the Pentax line of cameras will never be supported but at the moment it’s not on the plan due to restrictions on the way we might be able to interact with the camera.

      Best Regards,
      Dave

      Reply
  • Steve Tenney says:

    How about calibration with the Nikon TC-1.4EII teleconverter. I’ve completed the calibration and gotten values like +5, +13, +1 & +4. Consistently getting poor fit result on the Nikkor 300mm f/4D IF-ED lens. The lens by itself shows a -2 with a Good fit result.

    Thanks

    Reply
    • Hi Steve,

      You should be able to get the lens+TC to give accurate results, worth checking the FAQ What does “Fit Quality” mean within FoCal calibration results?. It may come down to lighting, often more light is better as it provides a faster shutter speed (reducing any shot vibration) but also helps the AF system itself to be more consistent. Do raise a support ticket if we can help further (blog comments aren’t the best place for support!) 🙂

      Best Regards,
      Dave

      Reply
    • Hi Rudi,

      At the moment the Nikon D850 is not supported by FoCal, but support is coming soon!

      Nikon has not yet provided an update to their comms library module for the Nikon D850, this is needed by FoCal before we can provide support. The Nikon library is normally made available around a month or so of the camera being released.

      We’ve done all the up-front work possible and once we have the updated software from Nikon it will likely take a couple of weeks for an updated version of FoCal 🙂

      Best Regards,
      Dave

      Reply
  • Chris Patterson says:

    Hi Focal. I am a subscriber to your newsletter. Are you guys engaging with Nikon to get the timing on the update to their comms library module for the Nikon D850?

    Reply
    • Hi Chris,

      Thank you for your interest in FoCal.

      We have been waiting for the update from Nikon for the comms library.

      Earlier this week (late Tuesday) Nikon went ahead and provided the update so work can progress!

      Always tricky to have a exact timescale (development is not always a straight line!) but we’re aiming for 3 weeks or so 🙂

      Best Regards,
      Dave

      Reply
  • I’m a little confused by how automatic the AF calibration is. I see both ‘fully automatic’ and also ‘user assisted’. That seems contradictory. Can you explain? Is it just a single press of a key from a computer, and then Focal does everything else ? Or is there something manual that I must do? Do I have to enter trial calibration values manually? If so, how many ? Thx for your help !

    Reply
    • Hi Alfred,

      Thank you for your interest in FoCal.

      Best place to look is the Supported Cameras List – it shows which cameras are “Hands Free” and which are “User Assisted” – along with a description and link to a video showing the operation.

      Best Regards,
      Dave

      Reply
    • Hi Joe,

      Thank you for your interest in FoCal.

      The Tamron TAP and Sigma Dock work in essentially the same way, we’ve written up some notes for the Sigma Dock but they are equally applicable to the TAP (just use the work TAP where it mentions Dock below)

      FoCal can be used with the Sigma Dock. Easiest way to think of it is this: the normal camera/lens calibration is a fine tune setting held in the camera and FoCal can be used to work out the best value for this setting. With the Sigma Dock you now have a lot more points of adjustment and they must be set inside the lens rather than inside the camera.

      To get an idea of what is involved I’ve linked to some posts where users describe calibrating using the Sigma Dock with the help of FoCal, http://www.dpreview.com/forums/thread/3809354 and the related thread linked by tektrader where they talk in more detail about the steps. More threads which talk about dock calibration using FoCal are https://www.dpreview.com/forums/thread/4031928 and https://www.dpreview.com/forums/thread/4052613 and another more recent thread at https://www.dpreview.com/forums/thread/4083573

      We don’t have an official written down procedure or tutorial video (yet!) but from what we understand FoCal can be useful for Sigma lens calibration. We’ll need to do our own tests and more research using multiple different Sigma lenses before we’ll have an official procedure that we guarantee will work in all cases.

      Different Sigma lenses require difference calibration distances and are given in the Sigma Dock software. The distance, especially for the close in distances should be fairly accurately measured (measure to the sensor plane usually indicated on the top of the camera).

      FoCal generally expects the target to take up between 20%-90% of the vertical frame. With nearer distances you might find a standard printed target works fine for this, if the target is taking up most or all of the screen you can re-print the target smaller as needed to ensure that it still fits inside the 90% with the closest distance.

      With further distances and indeed with the ‘infinity’ setting it’s unlikely you can print a FoCal target large enough for this calibration. The “infinity question” as I’m calling it is an interesting one(!) See some thoughts below on this, both from the point of view of picking a target as well as the point of view of what “infinity” might mean in Sigma terms.

      I think the best way round is to find a natural or environmental target and use that instead. So turn off the function where FoCal expects a target (“Preferences” > “Tests” you can tell FoCal not to look for the specific target design at all by setting “Target Validation” to “No Target Validation”).

      A ‘natural target’ would be anything with high contrast edges in both the vertical and horizontal axis. Perhaps a large road sign with text on it, or a high rise apartment block that has strong defined lines (say window frames).

      How far is “infinity” is somewhat unclear, Sigma should really tell its users what distance might be suitable for testing “infinity”, it’s difficult for us to weigh in on that question without knowing a lot more about the internal workings of the Sigma system. Our current thinking is something ‘a long way away’, which is fairly vague requirement(!)

      All the above is the approach we’ve come up with as suggestions, one of the things we want to do is provide more information to users and this will be happening soon.

      Essentially the expected process would be the calibrate (using FoCal) the lens at a specific distance (as given by Sigma in their user interface) and then try to dial out that adjustment. The end goal is the camera set AFMA ends up at 0 when the camera/lens is calibrated using FoCal and all the adjustment is entered instead within the Sigma Dock settings and held inside the lens itself.

      It’s hopeful (and there is some evidence to suggest) that once a relationship is found between AFMA / camera fine tune value and Sigma Dock calibration units that relationship holds true for further adjustments on that same lens.

      There’s also a video online from a FoCal user who mentions TAP calibration that might be worth checking out https://youtu.be/ku-qOGtB1vI 🙂

      Best Regards,
      Dave

      Reply

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