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Archive 2023 · Tips for consistent EyeAF with Z8

  
 
Jman13
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p.2 #1 · Tips for consistent EyeAF with Z8




JHut wrote:
What is the focus (subject) distance for these shots? Wide Area Mode w/ people subject detection? Custom focus box size? Hand off to 3D? If a specific very thin DOF is the goal here then maybe pinpoint AF on the pupil? The 105mm at f/1.4 and a subject 5 ft away then your DOF will be only 1/4". Move back from you subject to 10 ft or use f/5.6 and your DOF will improve to 1".


I’m aware of how DOF changes with distance. I’m aware that this requires very high precision. As I’ve noted, the issue is that the Z8 struggles with this level of precision in situations where the competition does not. I was trying to determine if there were settings or situations to improve this precision on the Z8, and right now it seems that there is not. I can work around it, for sure, but I wanted to make sure I wasn’t missing anything.

This, for example (again, more test shot than anything, as this is too shallow for what I really want), has barely a sliver in focus, as it’s near MFD, but I got the shot using small single focus point for AF, rather than Eye detect.

https://www.jordansteele.com/2023/x_veryclose.jpg



Aug 11, 2023 at 09:45 AM
jmmaher
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p.2 #2 · Tips for consistent EyeAF with Z8


I like a lot of things about the Z9 and Z8 but this lack of eye focus would frustrate me. I currently us a Sony A7R5 and this would not be an issue with that camera. Eye focus just works. Many things to love about the Nikon but this would put me off as much of what I shoot are portraits. Hopefully Nikon will address this as the new cameras are very interesting.


Aug 11, 2023 at 11:07 AM
mikard
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p.2 #3 · Tips for consistent EyeAF with Z8


Does fredmiranda have an ignore list, so I do not have to read this stuff. The title implies, maybe some autofocus tips for my Z8. Instead, I get TROLLS, and I would really like be able to not have to read the crap!


Aug 11, 2023 at 11:33 AM
Jman13
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p.2 #4 · Tips for consistent EyeAF with Z8




mikard wrote:
Does fredmiranda have an ignore list, so I do not have to read this stuff. The title implies, maybe some autofocus tips for my Z8. Instead, I get TROLLS, and I would really like be able to not have to read the crap!


Who is trolling? I’m genuinely looking for tips, as I’m fairly new to Nikon, and this one aspect of the camera isn’t performing how I would expect it to. I’ve been on FM for 18 years and have been a fairly contributory member, I’d like to believe.



Aug 11, 2023 at 11:57 AM
JHut
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p.2 #5 · Tips for consistent EyeAF with Z8



OK Gotcha. The brief time that I have had the Z8 the eye detection has worked well; Nonetheless, my subjects are always far past MFD (people and wildlife). The only time that I used the 105mm lens at MFD is for macro work and that always requires manual focus precision. Sorry that I can’t offer help with your test shots.

John

Edited on Aug 11, 2023 at 12:01 PM · View previous versions



Aug 11, 2023 at 12:00 PM
RoamingScott
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p.2 #6 · Tips for consistent EyeAF with Z8


Just out of curiosity, do you have auto subject detection on or human?


Aug 11, 2023 at 12:01 PM
Jman13
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p.2 #7 · Tips for consistent EyeAF with Z8




RoamingScott wrote:
Just out of curiosity, do you have auto subject detection on or human?


I’ve tried on both with minimal effect. These had human on.



Aug 11, 2023 at 12:05 PM
ilkka_nissila
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p.2 #8 · Tips for consistent EyeAF with Z8


I can recognize the OP's problem from a situation where I was using 85/1.8 S with the Z8 and took a few really tightly framed facial shots and they were pretty much the only case where I got the Z8 to miss focus. However, for a bit less tight shots (as you say, not near minimum focus distance) I can't really get it to miss on the eyes whether the subjects are static or moving. The othe case has been when it was iso 6400-12800, 1/400s, 105mm at f/1.4 in midsummer cloudy lighting outdoors and there it started to miss focus on some shots when the light became dim.

I have shot mostly with 24-70/2.8, 70-200/2.8, and the 1.8 primes with the Z8 and to me the camera has had rock solid focusing on the subject eyes for almost all situations. The two exceptions I mentioned above, one of a very tight head shot and the other in low light.

I typically use VR SPORT, define the area where the face of my main subject is likely to be and position a custom wide area rectangle in that part of the frame. I try to keep the shutter speed fast enough and use continuous AF with the AF-ON depressed, and human face/eye detection ON. I have selected focus+release priority. With this paradigm I have been very happy with the results and I can't see how they could be significantly better (apart from the lack of cross-type sensors which mainly affects me in wildlife but not people photography so much). I think it is worth excluding sources of error that might seem unlikely but could still affect the outcome. Try if a limited custom wide area box, fast shutter speed and VR SPORT rathern than NORMAL can help with the results if you have the time. I think failure or inconsistent results can be affected by multiple parameters and it's best to exclude their impact all at the same time.

JHut wrote:
OK Gotcha. The brief time that I have had the Z8 the eye detection has worked well; Nonetheless, my subjects are always far past MFD (people and wildlife). The only time that I used the 105mm lens at MFD is for macro work and that always requires manual focus precision. Sorry that I can’t offer help with your test shots.

John




Aug 11, 2023 at 12:27 PM
Lee Saxon
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p.2 #9 · Tips for consistent EyeAF with Z8


I don't think anybody has commented on what is to me the most interesting factor: the distribution of in- and out-of-focus shots isn't random. It looks like it took the camera six failed attempts to find the iris, but then once it did it held it for the next six. I don't know what that means, per se, but it's interesting.

Edited on Aug 11, 2023 at 06:18 PM · View previous versions



Aug 11, 2023 at 04:33 PM
AcuteShadows
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p.2 #10 · Tips for consistent EyeAF with Z8


Lee Saxon wrote:
I don't think anybody has commented on what is to me the most interesting factor: the distribution of in- and out-of-focus shots isn't random. It looks like it took the camera six failed attempts to find the iris, but then once it did it held it from the next six. I don't know what that means, per se, but it's interesting.


I was not assuming that the images were presented in chronological order, but I actually don't know.



Aug 11, 2023 at 05:26 PM
AcuteShadows
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p.2 #11 · Tips for consistent EyeAF with Z8


I wouldn't focus on a plane in front of the iris just to get the nose tip inside the depth of field.

But if you want to do zone focusing with portraits, then Nikon should offer the option of iris recognition and eye/zone recognition.

Anyway, if your depth of field is so narrow that you can't do proper zone focusing, having the eyelashes or eyebrows in focus, but neither the iris nor the nose is probably the second worst option (after setting the focal plane on the nose tip, that is).

Most portraits look good if you set depth of field so that the iris are in the focal plane and the eyebrows are within the depth of field. But with a narrower depth of field, I prefer to have the iris in focus.

If you are itching to shoot wide open not because of the kind of portrait you want to produce, but in order to blur the background, there is a decent chance that you simply have a bad background.



Aug 11, 2023 at 05:35 PM
Lee Saxon
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p.2 #12 · Tips for consistent EyeAF with Z8


AcuteShadows wrote:
I was not assuming that the images were presented in chronological order, but I actually don't know.


They are; the file names are visible (but small and easy to miss).

Steve Spencer wrote:
I think there can be too much emphasis on focus on the iris. For me when I take a portrait I want not only the iris to be in focus but the tip of the nose as well.


Yeah, this has been on my mind lately shooting with the GF 110/2. You can get comically shallow DoF with that lens.



Aug 11, 2023 at 07:26 PM
bernardl
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p.2 #13 · Tips for consistent EyeAF with Z8


I am getting excellent consistency with eye AF on the pupil with Z8/Z9 using various shallow AF lenses including 50mm f1.2 S, 85mm f1.2 S, 200mm f2.0 VR and 400mm f2.8 S shot close enough that pupil and eye lash have clearly different focus points. I even consider it a major strength of the Nikon AF compared to what I used to get with my Sony a9II.

For close up I get best results with AF-C set to trigger and focus, erratic with lowest delay setting (1) and all jpg image enhancing set to off.

I get worst results with AF-S even on supposedly static subjects due to the actual movements of subject and photographer. It matters on really shallow DoF situations like these.

Now, you son apparently standing outside has his eyes nearly closed (I assume due to bright conditions?) I tend to shoot in conditions where subject have their eyes opened. This may also have an impact.

Finally, although I personally tend to go to the edge of the gear because I bought bright lenses, the obvious reality is that 99.99% of historically successful portraits by the best photographers in the world were shot with significantly more DoF than what one gets with a 85mm f1.2 S up close. 😀

Cheers,
Bernard



Aug 15, 2023 at 12:04 PM
CanadaMark
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p.2 #14 · Tips for consistent EyeAF with Z8


Eye AF at F1.8 with my 85 1.8G is extremely consistent on my Z9 with the FTZ. Quite a noticeable difference from when I used that lens on my D850, but that is to be expected. I don't have a Z 85/1.8 or anything faster to try. Only difference I can see is I like to use 2-3X the shutter speed you are using to help compensate for my and my subject's movement, and I don't have the steadiest of hands.

I also am just not really a fan of the super shallow DOF close-up portraits so I usually shoot at either farther distances or at smaller apertures.



Aug 15, 2023 at 12:34 PM
OhSnap
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p.2 #15 · Tips for consistent EyeAF with Z8


Jman13 wrote:
I'm looking for some tips to maximize accuracy using EyeAF with the Z8, especially on shallow depth of field portraits. I am no stranger to the EyeAF algorithms of mirrorless cameras. I shot Sony for many years, and their EyeAF became quite good, though not entirely perfect. I shot Canon for several years recently, with the R5 and R8, and there, the EyeAF was essentially flawless. I could rely on the camera absolutely nailing focus on the eyeball with near 100% accuracy, even with ultra-fast lenses and very shallow depth of field. I shot an event for two hours with
...Show more

Nikon Z8: Hybrid with 493 phase-detection points and subject detection

Canon EOS R5: Dual Pixel CMOS AF II with 5,940 phase-detection points and subject detection

I've heard the Z8 sucks compared to the Z9 for hitting the eye, and the Z9 was borderline when I used it.

Everyone here will lie to you because this is a Nikon forum and tell you that's fine, and it's you, when it's not.

The shallower the depth of field, the worse it gets. For reference, I was shooting with the 200mm f/2 and 85mm f/1.2.



Aug 15, 2023 at 12:50 PM
dcisive
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p.2 #16 · Tips for consistent EyeAF with Z8


How odd. I had a Sony A7RV prior to my Z9. Sure, the eye autofocus was fine. Fast and for the most part accurate. But with the firmware update I got last for the Z9, it too for me, has been dead on in even challenging and surprising situations. Like lower light and such. Shooting my wife in the kitchen with very low light and moving around even. With my 24-120 S lens wide open nails each shot I take providing razor sharp eyes when in that mode. I have NO complaints nor weaknesses found in this setup. Not sure why some are having issues. One thing is for sure. When shooting flying birds, the Z9 runs rings around a A7RV.


Aug 15, 2023 at 12:54 PM
Jman13
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p.2 #17 · Tips for consistent EyeAF with Z8


OhSnap wrote:
Nikon Z8: Hybrid with 493 phase-detection points and subject detection

Canon EOS R5: Dual Pixel CMOS AF II with 5,940 phase-detection points and subject detection


I honestly think this might be the real reason. Nikon has 493 PD points, and to maintain speed, rather than truly focusing at the exact pinpoint spot where the eye is detected, the eye detection algorithm is (correctly) analyzing the frame, and simply selecting the closest focus point to the detected eye. If it happens to be over the iris, you get perfect focus. If it happens to be nearest the eyebrow, you get focus on the eyebrow. The points are in a 17x29 grid, and that's good coverage, but does have some small gaps that could cause issues in the right circumstances.

For sports / wildlife / portraits with any sort of normal depth of field, this works great, and results in wonderful accuracy. (And I've noticed it tracks extremely well). But for very shallow depth of field work, it can sometimes result in missing by a bit. I think that if I do find myself in a situation where I'm splitting this razor DOF and need the precision, using Pinpoint AF in AF-S is the way to go, as that appears to use CDAF to confirm focus, and the ability to select position is much finer than the 493 points.




Aug 15, 2023 at 01:32 PM
OhSnap
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p.2 #18 · Tips for consistent EyeAF with Z8


Jman13 wrote:
I honestly think this might be the real reason. Nikon has 493 PD points, and to maintain speed, rather than truly focusing at the exact pinpoint spot where the eye is detected, the eye detection algorithm is (correctly) analyzing the frame, and simply selecting the closest focus point to the detected eye. If it happens to be over the iris, you get perfect focus. If it happens to be nearest the eyebrow, you get focus on the eyebrow. The points are in a 17x29 grid, and that's good coverage, but does have some small gaps that could cause issues in
...Show more

Check your PMs.



Aug 15, 2023 at 01:38 PM
saaketham
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p.2 #19 · Tips for consistent EyeAF with Z8


At f/4, you won't notice the difference between focus on eye vs eyelash. OP is shooting at f/1.2, etc.

dcisive wrote:
How odd. I had a Sony A7RV prior to my Z9. Sure, the eye autofocus was fine. Fast and for the most part accurate. But with the firmware update I got last for the Z9, it too for me, has been dead on in even challenging and surprising situations. Like lower light and such. Shooting my wife in the kitchen with very low light and moving around even. With my 24-120 S lens wide open nails each shot I take providing razor sharp eyes when in that mode. I have NO complaints nor weaknesses found in this setup. Not sure
...Show more



Aug 15, 2023 at 02:00 PM
Jman13
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p.2 #20 · Tips for consistent EyeAF with Z8


So, I photographed the back of my Z8 with my Z7 II on a tripod, noting focus point positions, and at least with the boxes, they actually slightly overlap each other, which is interesting. I did create a grid with the exact bounds (minus the overlaps), and overlaid on portraits. The ones that missed focus most often had the iris of the detected eye split by focus points, (but not always). Those that hit, mostly had the iris inside a focus point, or mostly inside.

Example (the detected eye was his left eye, so rightmost in the image)
Slightly missed focus:
https://www.jordansteele.com/2023/x_oof.jpg

Perfect focus:
https://www.jordansteele.com/2023/x_infocus.jpg

However, this theory completely falls apart here, where his iris is dead in the center of a focus point, and yet the camera focused on his eyebrow.
https://www.jordansteele.com/2023/x_oof_bad.jpg

Still, I've shot some more, and I do get more hits than misses, so I think its certainly workable (I did some test portraits with me and remote shooting with eye detect with the 105/1.4, and it had perfect focus on about 80% of images).



Aug 15, 2023 at 02:22 PM
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