Z9, F Mount Lenses & Auto Fine Tune

[PAUL50]

I’ve noticed that the Z9 has a menu selection for Auto Fine Tune. My understanding is S type lenses on Z camera bodies do not require auto fine tuning. My question, if it’s true, then why is there an Auto Fine Tune menu selection in the Z9 menu. Will F mount lenses possibly require Auto Fine Tuning on Nikon’s mirrorless cameras and is that the reason why the Z9 has a menu selection for it. I’m really hoping no.

 

[Squatch]

With everything I’ve read about it, it’s my understanding that AF Fine Tune is still in the menus on Nikon Z cameras simply to give the photographer the option of creating a bit of front focus or back focus, simply for artistic purposes. It should not be needed for AF accuracy with any lenses, F-mount included.

I’ve shot my Z6II with nothing but F-mount lenses, and I’ve had zero issues with AF accuracy.

 

[PAUL50]

Thanks for the reply.

 

[EricBowles]

With everything I’ve read about it, it’s my understanding that AF Fine Tune is still in the menus on Nikon Z cameras simply to give the photographer the option of creating a bit of front focus or back focus, simply for artistic purposes. It should not be needed for AF accuracy with any lenses, F-mount included.

I’ve shot my Z6II with nothing but F-mount lenses, and I’ve had zero issues with AF accuracy.

This is exactly right. Fine tuning is normally not needed. I think it was Michael Tapes who stopped producing the LensAlign system because it simply was not needed for mirrorless (although I like his test targets).

I had a 70-200 F-mount lens that I was using with the Z6 and AF was perfect. I used it on my D850 and found it was backfocusing badly - 4-5 inches from 20 feet for more than 500 images. After proper testing, it went to Nikon for service and repair.

Having the ability to adjust focus if needed can be helpful. It provides an additional focus option - especially if normal focus on a target is not practical.

 

[Squatch]

This is exactly right. Fine tuning is normally not needed. I think it was Michael Tapes who stopped producing the LensAlign system because it simply was not needed for mirrorless (although I like his test targets).

I had a 70-200 F-mount lens that I was using with the Z6 and AF was perfect. I used it on my D850 and found it was backfocusing badly - 4-5 inches from 20 feet for more than 500 images. After proper testing, it went to Nikon for service and repair.

Having the ability to adjust focus if needed can be helpful. It provides an additional focus option - especially if normal focus on a target is not practical.

I previously owned a D500, D810, and D850, and had a 16-35mm f/4, a 70-200 f/4, a 105mm f/2.8 macro, a 200-500 f/5.6, and a 500mm f/4 G. I had to fine tune every single one of those lenses to each camera, and the 70-200, 105 macro, and the 500 f/4 a second time each with my TC14. On a whim, I bought a Z6II one day on my way back from an outing, and haven’t looked back. I have since streamlined my kit quite drastically…suffice it to say, I’ll never get on the NPS list, lol.
Mirrorless is it for me.

 

[thelordofthelight]

Just found this nice article about AFFT on mirrorless cameras. Very interesting read.

Reikan FoCal: Nikon Z9 Review & Analysis

A look at the Nikon Z9 with Reikan FoCal - an overview, playtime at Durdle Door and testing of VR and sharpness.

blog.reikanfocal.com

 

[PAUL50]

Just found this nice article about AFFT on mirrorless cameras. Very interesting read.

Reikan FoCal: Nikon Z9 Review & Analysis

A look at the Nikon Z9 with Reikan FoCal - an overview, playtime at Durdle Door and testing of VR and sharpness.

blog.reikanfocal.com

Thanks

 

[bjanes]

This is exactly right. Fine tuning is normally not needed. I think it was Michael Tapes who stopped producing the LensAlign system because it simply was not needed for mirrorless (although I like his test targets).

I had a 70-200 F-mount lens that I was using with the Z6 and AF was perfect. I used it on my D850 and found it was backfocusing badly - 4-5 inches from 20 feet for more than 500 images. After proper testing, it went to Nikon for service and repair.

Having the ability to adjust focus if needed can be helpful. It provides an additional focus option - especially if normal focus on a target is not practical.

I agree with Eric that fine tuning is usually not needed with the Z9 (and presumably with other Z cameras) but if you read Steve's auto focus for mirrorless book, It can be helpful in some cases. This is due to the way the Z9 handles phase detect focusing (Page 370). The PDAF takes a reading and tells the camera how much the focus needs to be changed and the camera makes the required adjustment, but does not check the focus afterwards. If the camera is slightly out of calibration the focus may not be precisely accurate and fine tuning may help but is not usually needed. If you want CDAF (contrast detect AF) confirmation use pinpoint focus in AFS.

Reikan Focal software is currently the only program to automatic this process. It also makes a number of useful measurements and compares the results to its database of other lenses in its database. I have used it extensively with the D850 and have noticed slight improvement with some lenses.

Bill

 

[EricBowles]

I agree with Eric that fine tuning is usually not needed with the Z9 (and presumably with other Z cameras) but if you read Steve's auto focus for mirrorless book, It can be helpful in some cases. This is due to the way the Z9 handles phase detect focusing (Page 370). The PDAF takes a reading and tells the camera how much the focus needs to be changed and the camera makes the required adjustment, but does not check the focus afterwards. If the camera is slightly out of calibration the focus may not be precisely accurate and fine tuning may help but is not usually needed. If you want CDAF (contrast detect AF) confirmation use pinpoint focus in AFS.

Reikan Focal software is currently the only program to automatic this process. It also makes a number of useful measurements and compares the results to its database of other lenses in its database. I have used it extensively with the D850 and have noticed slight improvement with some lenses.

Bill

My understanding and experience is AF is always using hybrid Phase Detect/Contrast Detect. The difference is Pinpoint is Contrast Detect only. There was some early incorrect information from Thom Hogan suggesting that normal focus was Phase Detect only - and that was later corrected. Nikon has said AF Fine Tuning is not normally needed. My testing has only shown a material need for Fine Tuning if I wanted to bias focus.

In the field, I had a Nikon 70-200 f/2.8 VR II used on a Z6 that provided perfect AF. The same lens used on a D850 with Phase Detect AF only was backfocusing 4 inches from 25 feet (for a shoot of more than 500 images every image had exactly the same backfocusing). This was outside the range where AF Fine Tuning provided adequate correction (during subsequent testing). The lens needed service by Nikon. But - the AF was perfect over thousands of images with the Z6.

The Reikan article shows aggregate user test data, and is probably directionally correct, but the feedback covers all lenses and Reikan did not actually do any testing. There are a lot of sources of variation and test error even with very good testing and methodology using the Reikan system.

 

[bjanes]

My understanding and experience is AF is always using hybrid Phase Detect/Contrast Detect. The difference is Pinpoint is Contrast Detect only. There was some early incorrect information from Thom Hogan suggesting that normal focus was Phase Detect only - and that was later corrected. Nikon has said AF Fine Tuning is not normally needed. My testing has only shown a material need for Fine Tuning if I wanted to bias focus.

In the field, I had a Nikon 70-200 f/2.8 VR II used on a Z6 that provided perfect AF. The same lens used on a D850 with Phase Detect AF only was backfocusing 4 inches from 25 feet (for a shoot of more than 500 images every image had exactly the same backfocusing). This was outside the range where AF Fine Tuning provided adequate correction (during subsequent testing). The lens needed service by Nikon. But - the AF was perfect over thousands of images with the Z6.

The Reikan article shows aggregate user test data, and is probably directionally correct, but the feedback covers all lenses and Reikan did not actually do any testing. There are a lot of sources of variation and test error even with very good testing and methodology using the Reikan system.

That is not how I interpret Steve's explanation. Of course, he could be mistaken.

Steve's autofocus for mirrorless, page 375:

"The thing is, unlike CDAF, PDAF doesn’t “massage” the focus like that - it
would take too long. It merely looks at the phase difference and tells the
lens how far to spin the focus ring."

Best regards,

Bill

 

[EricBowles]

That is not how I interpret Steve's explanation. Of course, he could be mistaken.

Steve's autofocus for mirrorless, page 375:

"The thing is, unlike CDAF, PDAF doesn’t “massage” the focus like that - it
would take too long. It merely looks at the phase difference and tells the
lens how far to spin the focus ring."

Best regards,

Bill

That is a correct description of PDAF only. But I'm pretty sure Nikon has an additional step in their algorithm. I don't think it's possible to see a PDAF only step but it might exist in some circumstances. Technically, the focus ring is an electronic input and does not spin, so it's an electronic instruction to the focus motor to run for a specific time or to a specific point. CDAF has a similar instruction but moves the lens group a small amount to determine whether the change was better or worse, so it is processor dependant. I don't want to get to far into the technical details because it's beyond my area of specific knowledge. I discussed the hybrid AF directly with Mark Cruz of Nikon.

 

[bjanes]

That is a correct description of PDAF only. But I'm pretty sure Nikon has an additional step in their algorithm. I don't think it's possible to see a PDAF only step but it might exist in some circumstances. Technically, the focus ring is an electronic input and does not spin, so it's an electronic instruction to the focus motor to run for a specific time or to a specific point. CDAF has a similar instruction but moves the lens group a small amount to determine whether the change was better or worse, so it is processor dependant. I don't want to get to far into the technical details because it's beyond my area of specific knowledge. I discussed the hybrid AF directly with Mark Cruz of Nikon.

Please accept my apologies for persistence, but I think this is an important topic. Here is what
Thom says in his Z9 guide:

"Yes and no. The phase detection autofocus system used by Nikon in
the Z9 is generally accurate, but it is not always backed by a
contrast verification step. Indeed, contrast verification is not
performed most of the time; it’s only done in low light conditions or
with specific focus settings (e.g. Pinpoint AF)."

Regards,

Bill

 

[EricBowles]

Please accept my apologies for persistence, but I think this is an important topic. Here is what
Thom says in his Z9 guide:

"Yes and no. The phase detection autofocus system used by Nikon in
the Z9 is generally accurate, but it is not always backed by a
contrast verification step. Indeed, contrast verification is not
performed most of the time; it’s only done in low light conditions or
with specific focus settings (e.g. Pinpoint AF)."

Regards,

Bill

I understand - and believe he is wrong. Now there may be some difference in the frequency of the CDAF step. Supposedly the Z9 adjusts focus 120 times per second - so there is plenty of time for a CDAF adjustment. But that's different from what Mark Cruz said and he works for Nikon.

I'm not sure there is a way to confirm it outside of the impact on photos. My experience with a lens that needed repair and still produced perfect focus on the Z6 suggests there is a CDAF step with the Wide AF modes using AF-C.

Said another way, the data reported by Reikan for Z cameras shows very different performance compared to any DSLR from Nikon. It must be more than simply the on-sensor AF with PDAF. It's just not possible to enhance PDAF performance to that extent.

 

[bjanes]

I understand - and believe he is wrong. Now there may be some difference in the frequency of the CDAF step. Supposedly the Z9 adjusts focus 120 times per second - so there is plenty of time for a CDAF adjustment. But that's different from what Mark Cruz said and he works for Nikon.

I'm not sure there is a way to confirm it outside of the impact on photos. My experience with a lens that needed repair and still produced perfect focus on the Z6 suggests there is a CDAF step with the Wide AF modes using AF-C.

Said another way, the data reported by Reikan for Z cameras shows very different performance compared to any DSLR from Nikon. It must be more than simply the on-sensor AF with PDAF. It's just not possible to enhance PDAF performance to that extent.

Eric,

I did view Mark's Nikon autofocus video and at about 16:21 into the presentation he did mention hybrid PDAF/CDAF focusing. I do not know what to believe, but it is more or less academic since I am getting good results thus far without resorting to pinpoint focus or other special modes.

Regards,

Bill

 

[EricBowles]

Eric,

I did view Mark's Nikon autofocus video and at about 16:21 into the presentation he did mention hybrid PDAF/CDAF focusing. I do not know what to believe, but it is more or less academic since I am getting good results thus far without resorting to pinpoint focus or other special modes.

Regards,

Bill

Hi Bill

That's my take as well. As the Reikan link suggests, the amount of AF Fine Tuning is so much smaller than with a DSLR that it's much less of an issue now than a few years ago.

I remember a few years ago LensRentals.com looked at the distribution of AF errors for Phase Detect and Live View Contrast Detect for a DSLR. They found a range of AF errors - even with Live View. The value was the range of AF errors was much tighter with Live View, but absolute accuracy for the best images was about the same with each method. I suspect we're seeing the same now, and with fast motion in the equation it's hard to tell how much the focus errors are technique vs. technology.

 

[dorthzyx]

Does anyone fine tune their z lenses on their z9 and if so do you get good results. I had heard that fine tuning wasn't necessary with the z9, z lens combo but have recently read some reviews saying it make a pretty good difference. I have been pleased with the results I've been getting but every little improvement helps.

 

[MrFotoFool]

With mirrorless setups, meaning any Z body (including Z9) and any Z lens, you should not need to do lens calibration (aka fine tuning). Even when I used DSLR (first Canon 5D series then Nikon D850 and D500) I never once needed to calibrate my lenses. Not once. I went through well over a dozen lenses in those years and all worked great out of the box. I think the whole idea of lens calibration is grossly overrated (my local camera repair guy says the same thing).

 

[Woodyg3]

Since focusing is done by the image sensor rather than a separate focus sensor as with DSLRs, there shouldn’t be much need for calibration.

 

[MartyD]

I am a fan of the Reikan Focal software for focus calibration and other tools but I have never calibrated my lenses on my Z cameras.

Here is a link to information on the Reikan site that explains why they think it is worthwhile.

 

[Vincent_VdB]

I have owned a wide array of Nikon bodies starting with the D70s up to Z8 & 9 today and never did lens finetuning on a Nikon lens on a Nikon body.

 

[EricKlees]

The mirrorless camera eliminate the need to fine tune any lens. Lens a needed to fine tune in my D850 and D500 were 100% tack sharp (200-500 and 500PF) and any Z lens shouldn't need any fine tuning for sure.

 

[SCoombs]

You'll hear people say that mirrorless cameras eliminate any need to fine tune. On the other hand, MartyD posts a good link with a look at some reasons why it may be helpful. Personally I've fine tuned a few lenses on the Z8 and found that in at least one case it seemed to help.

 

[bleirer]

Just conjecture, but if Nikon uses a hybrid of phase detect and contrast detection, where one type would tell the lens how far to jump all at once, then it could be useful. Have to know more how focus worked on the specific camera.

 

[EricKlees]

You'll hear people say that mirrorless cameras eliminate any need to fine tune. On the other hand, MartyD posts a good link with a look at some reasons why it may be helpful. Personally I've fine tuned a few lenses on the Z8 and found that in at least one case it seemed to help.

I would think a Z lens needing AF fine tuning to be extremely rare less than 5%. I would also think that the lens would need a recalibration from Nikon or any other brand.

If there is a firmware update for the lens and if you did update, i might try running the update again.

 

[DonM]

I have fine tuned a number of lens on my D500 with good results. Some needed very little but others it made a significant difference. I recently acquired a Z8 and noticed that there is a fine tune option in the setup menu that looks like the one in the D500. I tried fine tuning my 500mm PF to the Z8 and while I could optimize with LensAlign when I entered that value in the camera it actually made the picture worse. I tried manually focussing and then focused with the camera. It actually went out of focus with the fine tune turned on in the menu. When I turned off fine tune the camera focused same as manual focus. I enquired of Nikon on this and was told they don't recommend focus fine tune. OK, why did they put it in the menu ???