p.2 #2 · Z8 extremely unreliable/inconsistent AF in mildly low light
armd wrote:
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 that’s 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. ...Show more →
The most surprising thing to me is that the AF point if placed by the user on the eye is very reliable (for me anyways) but the very same point when placed by the algorithm is like a coin flip or worse. Why the actual focusing system would behave differently in these two cases is a mystery to me.
If you haven't tried it, consider AF-S and the built in illuminator for a posed shoot - I have found it results in almost 100% reliable focus.
p.2 #3 · 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 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.
I used 50/1.2s, 85/1.2S, 135/1.8s quite a bit for half body low light portrait and upper torso/face shot with 50/1.2S across the table in very dim restaurant and an outdoor evening reception at a friend's wedding with 135/1.8 and 50/1.2S and my keeper rate is much much higher than 30%. I wonder if you might be one of the people who may suffer from this?
p.2 #4 · Z8 extremely unreliable/inconsistent AF in mildly low light
Another thought for those who haven't had as many problems:
I have found from my testing that it seems as if the system is more likely to have accurate focus on the initial acquisition than after the AF-C tries to maintain focus, meaning that if I let the shutter button activate focus and shoot that way I get more hits than if I use my normal approach of back button focus. If I use back button but try to hit the shutter the *instant* the system gives me a green box, I also have better success.
This is also consistent with the finding that in AF-S subject detect seems to work better.
It's as if the initial acquisition is generally good and then the system immediately starts moving around.
So if you're not usually using back button focus, you may have noticed this less.
p.2 #5 · Z8 extremely unreliable/inconsistent AF in mildly low light
suteetat wrote:
I used 50/1.2s, 85/1.2S, 135/1.8s quite a bit for half body low light portrait and upper torso/face shot with 50/1.2S across the table in very dim restaurant and an outdoor evening reception at a friend's wedding with 135/1.8 and 50/1.2S and my keeper rate is much much higher than 30%. I wonder if you might be one of the people who may suffer from this?
p.2 #6 · Z8 extremely unreliable/inconsistent AF in mildly low light
SCoombs wrote:
Another thought for those who haven't had as many problems:
I have found from my testing that it seems as if the system is more likely to have accurate focus on the initial acquisition than after the AF-C tries to maintain focus, meaning that if I let the shutter button activate focus and shoot that way I get more hits than if I use my normal approach of back button focus. If I use back button but try to hit the shutter the *instant* the system gives me a green box, I also have better success.
This is also consistent with the finding that in AF-S subject detect seems to work better. ...Show more →
I have encountered this behaviour, e.g., when photographing birds in low light; the initial focus is better than the focus when the sequence is continued.
However, I use custom function a1 set to focus + release so this behavior is expected. The camera will check the focus before allowing the shot to be taken on the first shot of the sequence and not so much for the subsequent shots, where it is taking less time to check focus before releasing, to keep the sequence fps rate constant.
In order to improve the situation one could set a1 to focus priority and then the camera will do more work before each shot to ensure focus, but you may lose a bit on the actually realized fps rate if you are shooting a burst.
I am not saying this isn't an issue, clearly the camera isn't working as well as it might, but at least the users have some recourse when this problem is occurring, by adjusting the setting. Nikon should work on their algorithms for autofocus to improve consistency, but for now, this is what we have.
p.2 #7 · Z8 extremely unreliable/inconsistent AF in mildly low light
ilkka_nissila wrote:
I have encountered this behaviour, e.g., when photographing birds in low light; the initial focus is better than the focus when the sequence is continued.
However, I use custom function a1 set to focus + release so this behavior is expected. The camera will check the focus before allowing the shot to be taken on the first shot of the sequence and not so much for the subsequent shots, where it is taking less time to check focus before releasing, to keep the sequence fps rate constant.
In order to improve the situation one could set a1 to focus priority and then the camera will do more work before each shot to ensure focus, but you may lose a bit on the actually realized fps rate if you are shooting a burst. ...Show more →
Unfortunately this doesn't help because the real issue is not that the system can't achieve a state where it thinks it has focus: it's that it is in low light often wrong when it thinks it does.
When I am having these issues the AF-C gives the green "focus acquired" indicator basically at 100% uptime. It reports focus acquired and tracked full time, so the shutter will release when set to release on focus only. The issue is that the system is wrong about *where* the focus is. I have tested this for what it's worth.
p.2 #8 · Z8 extremely unreliable/inconsistent AF in mildly low light
Just did a studio shoot with Z8/Z9, pretty darkish environment. Most images tack sharp on the eye at f2.8 using 50mm f1.2 S, 85mm f1.2 S and 135mm f1.8 S.
I use AF-C, customer mode 2 with people subject detection, erratic, lowest possible response time.
p.2 #9 · Z8 extremely unreliable/inconsistent AF in mildly low light
I'm kind of scratching my head as to why, as iso 2000 at f4 and 1/200 isn't that dark. I often shoot at f5.6-8 in a darkened studio at iso 100 and 1/200 on my Z8 (typically with the 24-120 f4 S or an adapted f-mount lens), and don't have noticeable issues with finding focus. I've shot weddings and events with the Z8 and Z9 at f1.8 iso 6400 ss 1/250 with the Z8, Z9 and Z6ii and also no issues there.
I wonder if it's because they have blue eyes. I sometimes find that blue eyes are a little harder for the eye-detect to find. If all else fails though, just stopping down tends to solve it in terms of depth of field. This is kind of an issue with all mirrorless cameras I've owned, and why I keep my D850 as the single AF point tends to be more sensitive in dark situations.
p.2 #10 · Z8 extremely unreliable/inconsistent AF in mildly low light
So I predominantly shoot trail ultra marathons and shoot most of the time in terrible lighting conditions. I'm in and around caves, tree canopy, am usually shooting early in the mornings, late in the evenings and after sunset into the night and overnight. The experience of the OP is nothing like my experience with the Z8. In low light I primarily use the 85mm 1.2 and 135mm 1.8. Overnight, I am often focusing on runners with very little ambient light and then firing a flash. The Z8 is the best low light camera I've used. Shooting up to 10,000 ISO I have an almost 100% keeper rate with the 85mm 1.2 wide open. I just don't worry about it missing. When I'm shooting in near darkness with flash that keeper rate obviously drops, but I would still put it well above the 30% OP is finding. It is remarkably reliable in exceptionally challenging conditions.
p.2 #11 · Z8 extremely unreliable/inconsistent AF in mildly low light
sungphoto wrote:
I'm kind of scratching my head as to why, as iso 2000 at f4 and 1/200 isn't that dark. I often shoot at f5.6-8 in a darkened studio at iso 100 and 1/200 on my Z8 (typically with the 24-120 f4 S or an adapted f-mount lens), and don't have noticeable issues with finding focus. I've shot weddings and events with the Z8 and Z9 at f1.8 iso 6400 ss 1/250 with the Z8, Z9 and Z6ii and also no issues there.
I wonder if it's because they have blue eyes. I sometimes find that blue eyes are a little harder for the eye-detect to find. If all else fails though, just stopping down tends to solve it in terms of depth of field. This is kind of an issue with all mirrorless cameras I've owned, and why I keep my D850 as the single AF point tends to be more sensitive in dark situations....Show more →
It's not that eye detect doesn't have difficulty finding the eye - it doesn't - though the results aren't accurate. Past findings suggested that Nikon had a tendency to focus on the lashes rather than the eye itself. That is really an aside though one of the vexing issues is that one cannot diagnose this easy in post as the exif doesn't record distance and there is some question as to whether the actual AF point is the one displayed in NxStudio.
Quite candidly, I haven't taken the time to determine whether AF-S is more accurate than AF-C. My solution has been to either turn off subject detect and use a spot focus or just shoot large sequences and play the odds that one shot will be in focus.
p.2 #12 · Z8 extremely unreliable/inconsistent AF in mildly low light
sungphoto wrote:
I'm kind of scratching my head as to why, as iso 2000 at f4 and 1/200 isn't that dark. I often shoot at f5.6-8 in a darkened studio at iso 100 and 1/200 on my Z8 (typically with the 24-120 f4 S or an adapted f-mount lens), and don't have noticeable issues with finding focus. I've shot weddings and events with the Z8 and Z9 at f1.8 iso 6400 ss 1/250 with the Z8, Z9 and Z6ii and also no issues there.
I wonder if it's because they have blue eyes. I sometimes find that blue eyes are a little harder for the eye-detect to find. If all else fails though, just stopping down tends to solve it in terms of depth of field. This is kind of an issue with all mirrorless cameras I've owned, and why I keep my D850 as the single AF point tends to be more sensitive in dark situations....Show more →
The examples I posted happen to be blue eyes, but I've had the same thing with eyes of all sorts.
p.2 #13 · Z8 extremely unreliable/inconsistent AF in mildly low light
armd wrote:
It's not that eye detect doesn't have difficulty finding the eye - it doesn't - though the results aren't accurate. Past findings suggested that Nikon had a tendency to focus on the lashes rather than the eye itself. That is really an aside though one of the vexing issues is that one cannot diagnose this easy in post as the exif doesn't record distance and there is some question as to whether the actual AF point is the one displayed in NxStudio.
Quite candidly, I haven't taken the time to determine whether AF-S is more accurate than AF-C. My solution has been to either turn off subject detect and use a spot focus or just shoot large sequences and play the odds that one shot will be in focus....Show more →
I have found the AF works well enough when you're not asking it to perform miracles. Tiny humans with light colored eyes in a dark room are a hard one for any camera. I think the OP just needs to get to know the camera better and its limits.
Generally AF-S is going to be more accurate than AF-C, based on a couple decades of shooting canon, nikon, sony, fuji etc. Any camera is going to have challenges with super shallow depth of field in low light with fast moving objects.
p.2 #14 · Z8 extremely unreliable/inconsistent AF in mildly low light
SCoombs wrote:
The examples I posted happen to be blue eyes, but I've had the same thing with eyes of all sorts.
I'm not sure what the issue could be honestly. Even my Z6ii isn't as bad in terms of low light AF as what you're describing. I've gotten sharp focus on the eyes in dark rooms of a black cat with my Z8.
p.2 #15 · Z8 extremely unreliable/inconsistent AF in mildly low light
nhmorgan wrote:
So I predominantly shoot trail ultra marathons and shoot most of the time in terrible lighting conditions. I'm in and around caves, tree canopy, am usually shooting early in the mornings, late in the evenings and after sunset into the night and overnight. The experience of the OP is nothing like my experience with the Z8. In low light I primarily use the 85mm 1.2 and 135mm 1.8. Overnight, I am often focusing on runners with very little ambient light and then firing a flash. The Z8 is the best low light camera I've used. Shooting up to 10,000 ISO I have an almost 100% keeper rate with the 85mm 1.2 wide open. I just don't worry about it missing. When I'm shooting in near darkness with flash that keeper rate obviously drops, but I would still put it well above the 30% OP is finding. It is remarkably reliable in exceptionally challenging conditions. ...Show more →
I wonder what the explanation is as there are many like you who report great, near perfect performance but also many like me who report struggles in low light. It sometimes feels like people have two different cameras.
One might put something up to user error, but most (myself included) with this experience say they have very good performance in better light.
That said, reading through the comments here and dpreview one trend I notice is people who report no problems talking about shooting wider angle shots (even if using a longer focal length). For instance, are you shooting mainly runners *full body*? If Inshoot full body I don't have too many problems as a miss of an inch can still look perfectly in focus. It's when the depth of field is smaller with a tighter shot that it really shows up more consistently.
p.2 #16 · Z8 extremely unreliable/inconsistent AF in mildly low light
I wonder... for those reporting no problems, what information do you include on the display? Do you have the histogram? The horizon? Do you have a lot of the display information active, or a little?
Do you use VR/IBIS when shooting in these lower light scenarios? Normal or Sport?
p.2 #17 · Z8 extremely unreliable/inconsistent AF in mildly low light
SCoombs wrote:
I wonder what the explanation is as there are many like you who report great, near perfect performance but also many like me who report struggles in low light. It sometimes feels like people have two different cameras.
One might put something up to user error, but most (myself included) with this experience say they have very good performance in better light.
That said, reading through the comments here and dpreview one trend I notice is people who report no problems talking about shooting wider angle shots (even if using a longer focal length). For instance, are you shooting mainly runners *full body*? If Inshoot full body I don't have too many problems as a miss of an inch can still look perfectly in focus. It's when the depth of field is smaller with a tighter shot that it really shows up more consistently. ...Show more →
There are a near infinite number of variables that could differ. The first I would consider is the subject. Baby skin is very soft and textureless, harder for the AF system to use as a guide even though it should be predominately using the eye. Have you seen this issue with other subjects?
p.2 #18 · Z8 extremely unreliable/inconsistent AF in mildly low light
snapsy wrote:
There are a near infinite number of variables that could differ. The first I would consider is the subject. Baby skin is very soft and textureless, harder for the AF system to use as a guide even though it should be predominately using the eye. Have you seen this issue with other subjects?
Yes, this applies to all subjects - or all living ones, anyways. I also see it with the animal and bird modes when shooting those creatures, but not as often. Others above have also talked about seeing it with engagement shoots, etc.
p.2 #19 · Z8 extremely unreliable/inconsistent AF in mildly low light
sungphoto wrote:
I have found the AF works well enough when you're not asking it to perform miracles. Tiny humans with light colored eyes in a dark room are a hard one for any camera. I think the OP just needs to get to know the camera better and its limits.
Generally AF-S is going to be more accurate than AF-C, based on a couple decades of shooting canon, nikon, sony, fuji etc. Any camera is going to have challenges with super shallow depth of field in low light with fast moving objects.
I know my camera quite well, as do others who experience this behavior.
Let me put it this way: it is literally impossible for me to take any photograph with flash without dealing with this while in AF-C. If the lighting is such that flash is required, the subject detection will give me missed focus of an inch or more two thirds of the time. I get what you're saying and for more traditional DSLR style focus9ng I'd agree... but I don't think by any means its asking for a miracle to expect to be able to use the camera's main focusing feature for flash photography. Do you think that's reasonable?
p.2 #20 · Z8 extremely unreliable/inconsistent AF in mildly low light
SCoombs wrote:
I know my camera quite well, as do others who experience this behavior.
Let me put it this way: it is literally impossible for me to take any photograph with flash without dealing with this while in AF-C. If the lighting is such that flash is required, the subject detection will give me missed focus of an inch or more two thirds of the time. I get what you're saying and for more traditional DSLR style focus9ng I'd agree... but I don't think by any means its asking for a miracle to expect to be able to use the camera's main focusing feature for flash photography. Do you think that's reasonable? ...Show more →
I think most of the time these issues on the Z8 and Z9 are due to camera setup or user technique. The Z6 and Z7 for sure have issues, but to be honest what you're describing doesn't make sense to me
