Home · Register · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Nikon Forum | Join Upload & Sell

       2       3              19       20       end
  

Z8 extremely unreliable/inconsistent AF in mildly low light

  
 
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #1 · p.1 #1 · Z8 extremely unreliable/inconsistent AF in mildly low light


This is an issue I've been fighting with and trying to get a better handle on for a while: in even just slightly lower light, I have found the Z8's subject detection to become extremely unreliable, especially in AF-C.

To be clear, by "slightly lower light" I'm not talking about anything extreme, but something like "there's bright sunlight streaming in through my bay windows and I have someone standing 15 feet away where the sun isn't reaching so I need ISO 2000 at f4 and 1/200" sort of low light.

Also to be clear, by "extremely unreliable" I don't mean that subject detection doesn't work, but that it detects the subject and puts the focus point on the eye and it is green but my in-focus hit rate is <33%.

I've messed around with this a lot and found the following to be true:

1) With any kind of non-subject detect mode the in-focus rate goes up a ton. It's still not perfect in this sort of light, but for instance using single point or one of the dynamic areas in AF-C works far, far more reliably.

2) When going to AF-S, the non-subject detect modes get even better.

3) If I turn on the green AF-assist light in AF-S, it nails things pretty much 100% of the time.

4) I've tried the "adjust settings for ease of viewing" and it sort of improves things, but not much.

5) Starlight mode sort of works in much darker lighting to bring things up to the level of this "sort-of-low light" scenario but still just leaves me with the 33% hit rate instead of not functioning at all.

6) When the subject detect misses in this sort of light (so about 2/3 of the time) it seems to miss by back-focusing a LOT. For instance, it's very, very common if someone is turned at a 45 degree angle that when subject detect is focusing on the front eye and misses, I find the back eye to be very nicely in focus.

Is this really as good as it gets with this system right now? I have seen plenty of people really extol how amazing they find the AF to work in lower light, so I'm hoping there's something I'm missing here. Any help?



Apr 25, 2024 at 05:15 PM
HibikiRush
Offline

Upload & Sell: Off
p.1 #2 · p.1 #2 · Z8 extremely unreliable/inconsistent AF in mildly low light


The Z8 and the Z9 are terrible performers in low-light AF and I do not recommend them for anyone that works in these environments. This is something Nikon really needs to address with their next cameras, and hopefully the Z6 III is that. Since original firmware the Z9 (I do not have a Z8 but I am assuming they both function the same) has improved slightly, although it is still unreliable.

I have a D6 always in my bag for whenever I end up in a dim area as I know I cannot trust the Z9 to nail autofocus. I work in entertainment events and the consensus among my colleagues is the same regarding the Z9 - they don't like it. Don't get me wrong, when you do have the light it's a great camera and I do enjoy using it. When you lose that light, forget it and pray that it doesn't misfocus on an important shot.

Nikon needs to do better next gen. A lot better. I have tried the R3 side by side with the Z9 and it flies with autofocus in dim situations.



Apr 25, 2024 at 09:24 PM
dcisive
Offline
• • •
Upload & Sell: Off
p.1 #3 · p.1 #3 · Z8 extremely unreliable/inconsistent AF in mildly low light


Of course a R3 will exceed performance in low light. It's a lower megapixel that has larger pixels so gathering more light. However since the Ver. 5 update on my Z9 I'm getting outstanding performance in very low light shooting situations. I just set it to an upper limit of ISO6400, with People subject detection and the Wide/Large box and it instantly grabs a persons eye in very poor light indoors. This is with a 24-120 f4 S lens. I have a friend that has both the Z9 and R3 and has exhaustively tested them against each other. We've determined the R3 has about a stop better overall performance then a Z9 at ISO's above 6400.


Apr 25, 2024 at 10:04 PM
1bwana1
Online
• • • • • •
Upload & Sell: On
p.1 #4 · p.1 #4 · Z8 extremely unreliable/inconsistent AF in mildly low light


What the OP is posting about has zero to do with ISO.


Apr 25, 2024 at 10:22 PM
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Z8 extremely unreliable/inconsistent AF in mildly low light


dcisive wrote:
Of course a R3 will exceed performance in low light. It's a lower megapixel that has larger pixels so gathering more light. However since the Ver. 5 update on my Z9 I'm getting outstanding performance in very low light shooting situations. I just set it to an upper limit of ISO6400, with People subject detection and the Wide/Large box and it instantly grabs a persons eye in very poor light indoors. This is with a 24-120 f4 S lens. I have a friend that has both the Z9 and R3 and has exhaustively tested them against each other. We've determined
...Show more

It does instantly recognize and "grab" the eye even in poor light indoors, but the eye is very frequently not actually in focus in light that is anything less than really quite good. This is, for whatever it's worth, with S-line lenses like the 70-200, the 24-120, the 85 1.8.

If shooting at a relatively short focal length or a relatively large distance to the subject (or both), I do get an in focus eye much of the time because the focus is close enough that it falls within the somewhat larger depth of field you get in these situations. However, if using longer focal lengths or if you are closer to the subject so that the depth of field is a bit more shallow the focus is usually not actually on the eye even though the camera's AF thinks it is.

So for instance I have found that shooting upper body shots I can usually expect a pretty decent hit rate, but with headshots or portraits where a longer focal length has been used for compression I am getting somewhere around 1/3 of the shots actually in focus on the eye with subject detect. Swap to single point in the same conditions and place that on the eye and I get more like 3/4 or more of the shots in focus on the eye. Go outside and shoot the same person using subject detection and I'll also get about 3/4 or more of the shots in focus. Switch to AF-S and use the AF-assist light and it's pretty much 100% in focus.



Apr 25, 2024 at 10:42 PM
tester_V
Offline
• •
Upload & Sell: Off
p.1 #6 · p.1 #6 · Z8 extremely unreliable/inconsistent AF in mildly low light


You guys are scaring me. I trust real people opinion....


Apr 25, 2024 at 11:55 PM
Ai_Print
Offline
• • •
Upload & Sell: Off
p.1 #7 · p.1 #7 · Z8 extremely unreliable/inconsistent AF in mildly low light


SCoombs wrote:
This is an issue I've been fighting with and trying to get a better handle on for a while: in even just slightly lower light, I have found the Z8's subject detection to become extremely unreliable, especially in AF-C.

To be clear, by "slightly lower light" I'm not talking about anything extreme, but something like "there's bright sunlight streaming in through my bay windows and I have someone standing 15 feet away where the sun isn't reaching so I need ISO 2000 at f4 and 1/200" sort of low light.

Also to be clear, by "extremely unreliable" I don't mean that
...Show more

Iím finding exactly the same issues lately Z8 and Z9, I feel like these cameras were doing much better with the above scenarios a couple of firmware updates ago. It gets bad enough at times that I have to punch in and manually focus it and hope the person does not rock back and forth too much.

I have a big out of town corporate job next week, I am going to see if prolonged use / on time might have something to do with it in regards to heat build up.



Apr 26, 2024 at 12:49 AM
IainD
Offline

Upload & Sell: Off
p.1 #8 · p.1 #8 · Z8 extremely unreliable/inconsistent AF in mildly low light


I don't know if this might help, but for AF to work properly in the Z9, the subject must be exposed well. In other words, the subject seems to need to look nice and bright in the viewfinder, otherwise AF will miss. Making sure the exposure on the exact area of the subject rather than averaging nicely on the whole frame has helped me.


Apr 26, 2024 at 01:29 AM
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #9 · p.1 #9 · Z8 extremely unreliable/inconsistent AF in mildly low light


IainD wrote:
I don't know if this might help, but for AF to work properly in the Z9, the subject must be exposed well. In other words, the subject seems to need to look nice and bright in the viewfinder, otherwise AF will miss. Making sure the exposure on the exact area of the subject rather than averaging nicely on the whole frame has helped me.


Yes, this is true and up to a point it helps to a point. It is why I many have reported that turning on the setting to adjust the viewfinder for ease of viewing or the setting to keep the viewfinder bright when flash is in use helps, as does Starlight mode, which essentially brightens the viewfinder as much as possible to allow the AF system to focus better. I have found this can make a difference to a point.

However it only helps to a point and so there is a point at which light levels are still not really all that low but at which it's nevertheless too low for the subject detection system to apparently focus well.

And it really is the subject detection system. As noted, when the subject is bright in the viewfinder any of the non-subject detection modes will work within reason when light levels are getting lower but subject detection modes will perform markedly worse.

Some examples, all using bounce flash with something in the area of 1/4 power on a relatively low powered speedlight, so sort of low light but really not nearly all that bad.

Subject detection. The EVF when I was taking the photo and NX studio both reported the AF was on the near eye. Where is it actually? On the pizza.






A few seconds later, this time using the non-subject detect dynamic area small, focus is perfect:







This next one's a crop just to make it easy to see the eyes. Subject detection. EVF and NX studio report focus on the near eye. Where is it really? The back eye:







A few seconds later with the non-subject detect dynamic area, focus is perfect:







Another example with subject detect. EVF and NX studio report focus on the eye. It's really on the little puff of hair up top:







I could post these all day. If I use a "dumb" mode in lowish light the focus is spot on 75% of the time and I am more than willing to accept something like a 25% miss rate as lighting decreases. If I can get a subject to stand still so I can use AF-S with the Z8's green AF assist light it's in focus basically 100% of the time. It's perfect. If I use subject detection of any kind in this light, I'm getting something like 70% of the shots where the system adamantly believes it's focused on an eye when the real plane of focus is actually several inches to the front or the back.






Apr 26, 2024 at 02:31 AM
ilkka_nissila
Online
• • • •
Upload & Sell: Off
p.1 #10 · p.1 #10 · Z8 extremely unreliable/inconsistent AF in mildly low light


Could you show what the light looks like without the flash (including ISO, aperture and shutter speed information)? (The flash won't help the AF.)

I don't think it's a question of the subject detection mistaking pizza for an eye, but the pizza has high-contrast texture which produces a meaningful contrast that the camera can focus on, while the eye surrounded by soft skin might not, in low light, produce adequate contrast-to-noise ratio for the system to work with.

I haven't really had difficulties with my Z8 in low light except when talking about extremely low light (such as 1/50s, f/1.4, ISO 25600 and backlight at that). I agree that having some direct light on the subject helps a lot. But mostly I use the D6 and Zf in low-light people and event photography and not the Z8 simply because the 20 and 24 MP sensors produce to my view better image quality in these conditions and the smaller files are faster to work with as well. I wildlife photography I have used the Z8 in fairly low light (1/200s, f/5.6, ISO 25600) and there can be difficulties for sure, but again the image quality wouldn't be that great even if the shots were in focus, and so I find the major limitation here the maximum aperture of the lens and the image quality that the sensor can produce at these ISO settings. I think the biggest focus limitation is related to the lack of cross-type sensors in the Nikon Z cameras (the D6 obviously has them, and is in some situations much more reliable, such as when the subject is in backlight and the background has brightly lit vertical lines). However, this is not consistently related to low light levels as it can happen in bright sunlight.

Canon has the advantage in low light because all of the sensor photosites are used for phase-detection whereas in the Nikon/Sony designs the phase-detection sensors constitute only a small part of the sensor area. However, the latter design has the advantage that the camera doesn't have to deal with twice as much data (i.e. 90 MP camera sensor when the files are delivered with 45 MP of data). I think some of Canon's overheating problems with the R5 are related to the quantity of data that has to be processed in their system.



Apr 26, 2024 at 03:48 AM
 


Search in Used Dept. 

suteetat
Offline
• • • •
Upload & Sell: Off
p.1 #11 · p.1 #11 · Z8 extremely unreliable/inconsistent AF in mildly low light


I am very surprise to hear this.
I use Z8/Z9 in nightclub, indoor sporting event, poorly lit restaurant, night time street photography etc with no problem at all.
I use Z8 in underwater housing when I scuba dive, even during night dive when I as using AF-C to shoot blanket octopus and only have small underwater flashlight as my only light source (I was using 2 strobes but that only lit up when I took the pictures, did not help with focusing) so I am really surprise
that anyone would say Z8 has unreliable focus in low light.
For night dive, I use either 105/2.8S macro or 60/2.8G with FTZ adapter usually with L or S wide area AF with no subject detection as there is nothing that Z8 would recognize down there but sometimes I forgot to turn off subject detection but
that had not make any difference for me so far.



Apr 26, 2024 at 04:00 AM
sjms
Offline
• • • • • • •
Upload & Sell: On
p.1 #12 · p.1 #12 · Z8 extremely unreliable/inconsistent AF in mildly low light





Apr 26, 2024 at 04:43 AM
bs kite
Offline
• • • • •
Upload & Sell: On
p.1 #13 · p.1 #13 · Z8 extremely unreliable/inconsistent AF in mildly low light


sjms wrote:








Apr 26, 2024 at 05:47 AM
bs kite
Offline
• • • • •
Upload & Sell: On
p.1 #14 · p.1 #14 · Z8 extremely unreliable/inconsistent AF in mildly low light


deleted



Edited on Apr 26, 2024 at 06:28 AM · View previous versions



Apr 26, 2024 at 06:18 AM
bs kite
Offline
• • • • •
Upload & Sell: On
p.1 #15 · p.1 #15 · Z8 extremely unreliable/inconsistent AF in mildly low light


SCoombs wrote:
This is an issue I've been fighting with and trying to get a better handle on for a while: in even just slightly lower light, I have found the Z8's subject detection to become extremely unreliable, especially in AF-C.

To be clear, by "slightly lower light" I'm not talking about anything extreme, but something like "there's bright sunlight streaming in through my bay windows and I have someone standing 15 feet away where the sun isn't reaching so I need ISO 2000 at f4 and 1/200" sort of low light.

Also to be clear, by "extremely unreliable" I don't mean that
...Show more

I'm surprised people actually expect an AF system to be this precise.

The following settings will solve the issue you have SCoombs.......

I've got my Z8 set to AF-ON and fn2 button assigned to Single Point AF.

Place the AF square on the child's eye and press/release the fn2 button.

If you wish, you can recompose before shutter release.

The whole process takes less than 2 seconds *and the AF is precise*..... every shot.

Robert


Edited on Apr 26, 2024 at 07:13 AM · View previous versions



Apr 26, 2024 at 06:27 AM
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #16 · p.1 #16 · Z8 extremely unreliable/inconsistent AF in mildly low light


suteetat wrote:
I am very surprise to hear this.
I use Z8/Z9 in nightclub, indoor sporting event, poorly lit restaurant, night time street photography etc with no problem at all.
I use Z8 in underwater housing when I scuba dive, even during night dive when I as using AF-C to shoot blanket octopus and only have small underwater flashlight as my only light source (I was using 2 strobes but that only lit up when I took the pictures, did not help with focusing) so I am really surprise
that anyone would say Z8 has unreliable focus in low light.
For night dive, I
...Show more

I've used it for indoor sports, an extremely dark comedy show, and concerts as well, and I did have success, so let me reiterate that this is about AF reliability, not that it can never get the shot. Even in a dark concert with shooting a lot I get photos that can be used, it's just that for any given shot I'll get about a 1/3 chance it's got the focus in the right place.

Second, I have found it's much, much better if we are talking about shooting from greater distances or shorter focal lengths where the depth of field is naturally brighter. If, when shooting in a concert for instance, I'm looking to get an entire person in the shot, the depth of field is usually enough that most of such photos are fine. If I try to go for an upper body only or a headshot where the depth of field is more shallow, the issues become a lot more apparent.

I also need to reiterate that I'm talking about subject detection only. Some of what you mention wouldn't be putting the subject detection to any use or wouldn't be triggering it even if it was set to on.




Apr 26, 2024 at 06:43 AM
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #17 · p.1 #17 · Z8 extremely unreliable/inconsistent AF in mildly low light


ilkka_nissila wrote:
Could you show what the light looks like without the flash (including ISO, aperture and shutter speed information)? (The flash won't help the AF.)

I don't think it's a question of the subject detection mistaking pizza for an eye, but the pizza has high-contrast texture which produces a meaningful contrast that the camera can focus on, while the eye surrounded by soft skin might not, in low light, produce adequate contrast-to-noise ratio for the system to work with.

I haven't really had difficulties with my Z8 in low light except when talking about extremely low light (such as 1/50s, f/1.4, ISO 25600
...Show more

If we were talking here about something like the wide area large box with no subject detection and the camera going after the pizza because it's got more contrast that would make perhaps some sense, but we're talking about the system confidently identifying the eye and putting a small AF box on it. There shouldn't be any way for the system to suddenly go after the pizza, which is not in this case blocking the eye and is not anywhere near the box the AF system reports it is using. Moreover, there are the other examples I posted where the focus landed on something else with about the same or with literally the same contrast as the eye it said it was focused on. I have posted some screencaps from NX Studio on DPreview which show the focus points.

It's also worth nothing that I'm far from the only one who has reported this experience, as evidenced by some of the posters in this thread as well as in plenty of other discussions on the topic in the past. On the other hand, I'd agree that some report not having the problem, and I've read enough threads to thus far not have been able to find an obvious difference in what people from either group are doing, how they're setting things up, how they're trying to use the AF, etc.

As far as natural light levels go, I don't have photos readily available to post of this but I have kept track of this and we're talking about anything on the darker end from something like ISO12800 at 1/160 f4 - which I'd admit is getting pretty dark - all the way to something more like ISO 3200 at f4 1/160, which is not all that bad, to something like ISO 1600 at f2.8 and a shutter in the range of 1/400, which is really not what I'd call extremely dark. Another way of putting it is that it happens in light that's low but still good enough that without the flash I can get usable photos.

Another way of putting it, and this is the most important practical issue, if the light is low enough that I need to use a flash *at all*, this whole dynamic comes into play. In other words, anytime I would ever need to use the flash I can't count on the system to focus on eyes more than 1/3 of the time unless I place a focus point manually.




Edited on Apr 26, 2024 at 07:08 AM · View previous versions



Apr 26, 2024 at 07:01 AM
SCoombs
Offline
• •
Upload & Sell: Off
p.1 #18 · p.1 #18 · Z8 extremely unreliable/inconsistent AF in mildly low light


bs kite wrote:
I'm surprised people actually expect an AF system to be this precise.

The following settings will solve the issue you have Coombs.......

I've got my Z8 set to AF-ON and fn2 button assigned to Single Point AF.

Place the AF square on the child's eye and press/release the fn2 button.

If you wish, you can recompose before shutter release.

The whole process takes less than 2 seconds *and the AF is precise*..... every shot.

Robert


As noted, it does work well with single point mode. Not "precise on every shot," but more like "close enough you can't usually notice it on three out of four shots."

This doesn't mean there's no reason to want to have the "eye-AF" working in situations where the flash is required, or that we can't find it weird that in the very same situation an AF point placed on the eye by the user will work very reliably while the same point place there by the subject detect system will usually not get good focus.



Apr 26, 2024 at 07:07 AM
story_teller
Offline
• • •
Upload & Sell: On
p.1 #19 · p.1 #19 · Z8 extremely unreliable/inconsistent AF in mildly low light


SCoombs wrote:
I've used it for indoor sports, an extremely dark comedy show, and concerts as well, and I did have success, so let me reiterate that this is about AF reliability, not that it can never get the shot. Even in a dark concert with shooting a lot I get photos that can be used, it's just that for any given shot I'll get about a 1/3 chance it's got the focus in the right place.

Second, I have found it's much, much better if we are talking about shooting from greater distances or shorter focal lengths where the depth of
...Show more

What specific lenses are you using? I didnít see that mentioned.



Apr 26, 2024 at 07:11 AM
armd
Offline
• • • •
Upload & Sell: On
p.1 #20 · p.1 #20 · Z8 extremely unreliable/inconsistent AF in mildly low light


SCoombs wrote:
I've used it for indoor sports, an extremely dark comedy show, and concerts as well, and I did have success, so let me reiterate that this is about AF reliability, not that it can never get the shot. Even in a dark concert with shooting a lot I get photos that can be used, it's just that for any given shot I'll get about a 1/3 chance it's got the focus in the right place.

Second, I have found it's much, much better if we are talking about shooting from greater distances or shorter focal lengths where the depth of
...Show more
Sadly, your observations are entirely accurate. I recently did a sunset engagement shoot in the islands using subject detect nearly 1/3rd or more images were misfocused. Fortunately, there were enough in focus photos to make the couple happy, though thatís because I intentionally overcompensated with the number of shots. I was astounded by the number of photos focused on the nose or elsewhere on the face even though the box was clearly on the eye. Compared to my Canon gear one would have to return to the 7d to achieve such poor results. I suspect that Nikon has less effective algorithms and the lack of dual pixel leads to the af inconsistencies . As you observed, turning off subject detect results in better accuracy.



Apr 26, 2024 at 07:18 AM
       2       3              19       20       end






FM Forums | Nikon Forum | Join Upload & Sell

       2       3              19       20       end
    
 

You are not logged in. Login or Register

Username       Or Reset password



This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.