Inconsistent AF performance with Z6/Z7 - using external flashes

[aniltulsi]

OP is not able to focus with the modeling light in the studio, but you are able to AF, using the 'glow' of the diffuser (not sure what it is, as diffuser don't have there own source of light, but only diffuses flash light), is it that the Z cameras are more sensitive to certain type of light? Is your colour of the 'glow' white or yellow or blue or something else?

In fact it does have a light source ...

I have three different kinds like this, shipped from Asia.

This is not the exact one I used, but similar. LED lights connected to a battery pack.

The faint LEDs enable you two "see" what you're doing at night, but they don't actually affect the picture. Once you nail focus, and fire the flash, that's what makes the image. The diffuser than does its work.

But the little battery pack + LED lights "glow," which enable the user to see what he's doing and enjoy night macro photography, night reptile photography, etc.

--
Please forgive: I use voice text, so there may be typos. Hopefully it still makes sense
~
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Interesting... Looks like the diffuser has blue light, and maybe, the Z camera focuses better in blue light???

 

[mrbr]

OP is not able to focus with the modeling light in the studio, but you are able to AF, using the 'glow' of the diffuser (not sure what it is, as diffuser don't have there own source of light, but only diffuses flash light), is it that the Z cameras are more sensitive to certain type of light? Is your colour of the 'glow' white or yellow or blue or something else?

In fact it does have a light source ...

I have three different kinds like this, shipped from Asia.

This is not the exact one I used, but similar. LED lights connected to a battery pack.

The faint LEDs enable you two "see" what you're doing at night, but they don't actually affect the picture. Once you nail focus, and fire the flash, that's what makes the image. The diffuser than does its work.

But the little battery pack + LED lights "glow," which enable the user to see what he's doing and enjoy night macro photography, night reptile photography, etc.

Interesting... Looks like the diffuser has blue light, and maybe, the Z camera focuses better in blue light???

The camera uses green/blue photosites to focus !

--
Greetings,
Marc

 

[goactive]

I have two Z6s original ones and we have shot over well over 250 jobs with them and most we use off camera flash on and have zero problems.

In summer I can shoot 6 days in a row doing portrait sessions and weddings and not get any out of focus images unless I do something wrong my self.

I shoot 100% of the time with a single focus point and never use any eye focus never needed it.

I use a Godox AD200 off camera flash.

When it gets dark out or like in studio you should turn off the view finder exposure vire as I note that the camera can not see as well but when you turn it off your view finder gets much brighter and the camera then can focus in almost compleat darkness.

We have shot meany time after sunset on the beach in the dark like this and it nales it.

We also shoot a lot into the sunset so the Z6 has to focus with very strong back sunlight and it works for us.

This was using the adptor and a Tamron 35-150 lens we use the most.

Here is one in very low light way after sunset with off camera flash so the camera has to focus on its onw with no other help. I am using a low shutter speed to bring in more of the background.

But if i have the live exposure view truned on it would not get this at all as the camera would not see as good.

--
Started shooting digital back with the first 2MP cameras. Over 20 cameras later still going. I shoot for a living - family and people portraits, weddings, Sports and a little of everything.

 

[olyflyer]

I started to use FF Z bodies early spring and I was very happy with both Z6 & Z7 including how AF performed during outdoors sessions - for mostly portraits, some fashion and street photos.

Now in late autumn I went back to the studio and I am using mainly external flashes radio trigerred remotely from the camera. It is Quadralite system. With such a setup I struggle a lot with the performance of my Z6&Z7 autofocus and I cannot figure out what is the reason?

The keepers ratio went down from about 90-95% of nicely sharp eyes during outdoor sessions to about 60% in the studio. I tried to compare Z6 and Z7 with two latest firmware versions 3.31 and 3.40. I was pretty restrictive with my judging - treating pictures as OOF whenever the focus slided visible towards the ears or nose instead of the eyes. I was using mainly AF-S, Auto-Area with eye detection but also single point AF. My keepers ratio was as follows:

In the EVF view both bodies performed substantially better with FW 3.40. The AF rectangles were stickier and recognized eyes and faces from a larger distance.

I am dissapointed with so many OOF pictures. Of course I understand that the light conditions are completely different in the studio where the only source of it are the leading bulbs (set mostly on medium or high power). But the thing is that AF confirms with a beep and on actual pictures the focus is missing - often set on the bacground like on below NX Studio screenshot:

NX Studio shows that focus point is on face but actual focus is on the column in the background :-(

It seems that AF accuracy is better when shooting without flash even in low light conditions.

Have anyone experienced similar problems and know how to solve them?

I think your conclusions are wrong. I have been using the Z7 for over three years now and have zero problems with focus accuracy using a flash.

I don't know what that screen capture shows, but it does not show that you have eye detection and in fact, not even face detection. Also, you should set focus priority if you want high hit rate. With release priority the risks for pushing the shutter release too soon or too late is too high, especially if the subject is not static. So my own conclusion from your "problem" description is that this is simple user / camera configuration error.

Focus accuracy is just as good with flash as it is without a flash. If it is too dark and there is not enough contrast then the camera may struggle, but that's what the AF assist LED is used for, or you have to add some modelling light, but especially this picture should represent zero problems. Of course, there can be an issue with your camera, but it is very unlikely that you have identical issues with both the Z6 and the Z7 you claim to have, so I don't actually think that this is a camera error.

 

[olyflyer]

OP is not able to focus with the modeling light in the studio, but you are able to AF, using the 'glow' of the diffuser (not sure what it is, as diffuser don't have there own source of light, but only diffuses flash light), is it that the Z cameras are more sensitive to certain type of light? Is your colour of the 'glow' white or yellow or blue or something else?

In fact it does have a light source ...

I have three different kinds like this, shipped from Asia.

This is not the exact one I used, but similar. LED lights connected to a battery pack.

The faint LEDs enable you two "see" what you're doing at night, but they don't actually affect the picture. Once you nail focus, and fire the flash, that's what makes the image. The diffuser than does its work.

But the little battery pack + LED lights "glow," which enable the user to see what he's doing and enjoy night macro photography, night reptile photography, etc.

Interesting... Looks like the diffuser has blue light, and maybe, the Z camera focuses better in blue light???

That's a D500. Red is the best for AF, after that it should be white. Blue is at the other end of the visible spectrum, so it should not be the best.

 

[olyflyer]

OP is not able to focus with the modeling light in the studio, but you are able to AF, using the 'glow' of the diffuser (not sure what it is, as diffuser don't have there own source of light, but only diffuses flash light), is it that the Z cameras are more sensitive to certain type of light? Is your colour of the 'glow' white or yellow or blue or something else?

In fact it does have a light source ...

I have three different kinds like this, shipped from Asia.

This is not the exact one I used, but similar. LED lights connected to a battery pack.

The faint LEDs enable you two "see" what you're doing at night, but they don't actually affect the picture. Once you nail focus, and fire the flash, that's what makes the image. The diffuser than does its work.

But the little battery pack + LED lights "glow," which enable the user to see what he's doing and enjoy night macro photography, night reptile photography, etc.

Interesting... Looks like the diffuser has blue light, and maybe, the Z camera focuses better in blue light???

The camera uses green/blue photosites to focus !

The mirrorless cameras need green light for best focus. For DSLR that should be red.

 

[wildblanket]

Did you use radio triggered external flashes?

Yes. I started the year with Phottix manual triggers and finished with Godox.

Could you share more of your Af settings please? Was IBIS on?

IBIS on, AF-C, wide area with face/eye detect, back button focus.

I also did some self portraits in a space with lower light levels. I used AF-S so that I could hear focus confirmation while in front of the camera with a remote trigger. My hit rate was lower but I don't think that was really a fair test as I was not behind the camera. I also used some dynamic area instead of wide area.

I have an impression that I could shoot sharp pictures at my ambient light level without flashes. But I haven't tested it. I need to try it :-

Good luck

Presumably you are not talking about Z6/7 here as the firmware update does not add Wide Area Face/Eye detect according to posts here, and the Z5/Z6ii/7ii firmware was not updated significantly, so I don't think that's the issue in this thread.

 

[mrbr]

OP is not able to focus with the modeling light in the studio, but you are able to AF, using the 'glow' of the diffuser (not sure what it is, as diffuser don't have there own source of light, but only diffuses flash light), is it that the Z cameras are more sensitive to certain type of light? Is your colour of the 'glow' white or yellow or blue or something else?

In fact it does have a light source ...

I have three different kinds like this, shipped from Asia.

This is not the exact one I used, but similar. LED lights connected to a battery pack.

The faint LEDs enable you two "see" what you're doing at night, but they don't actually affect the picture. Once you nail focus, and fire the flash, that's what makes the image. The diffuser than does its work.

But the little battery pack + LED lights "glow," which enable the user to see what he's doing and enjoy night macro photography, night reptile photography, etc.

Interesting... Looks like the diffuser has blue light, and maybe, the Z camera focuses better in blue light???

The camera uses green/blue photosites to focus !

The mirrorless cameras need green light for best focus. For DSLR that should be red.

Yes, the Z AF assist light is green and from dslr's it is red.

I have found follwing information in Thom Hogan's Z6 e-guide p608 ( recommended ! ) :

QUOTE

The Z series phase detect sensors live under blue and green filters,....

UNQUOTE

--
Greetings,
Marc

 

[mrbr]

I started to use FF Z bodies early spring and I was very happy with both Z6 & Z7 including how AF performed during outdoors sessions - for mostly portraits, some fashion and street photos.

Now in late autumn I went back to the studio and I am using mainly external flashes radio trigerred remotely from the camera. It is Quadralite system. With such a setup I struggle a lot with the performance of my Z6&Z7 autofocus and I cannot figure out what is the reason?

The keepers ratio went down from about 90-95% of nicely sharp eyes during outdoor sessions to about 60% in the studio. I tried to compare Z6 and Z7 with two latest firmware versions 3.31 and 3.40. I was pretty restrictive with my judging - treating pictures as OOF whenever the focus slided visible towards the ears or nose instead of the eyes. I was using mainly AF-S, Auto-Area with eye detection but also single point AF. My keepers ratio was as follows:

In the EVF view both bodies performed substantially better with FW 3.40. The AF rectangles were stickier and recognized eyes and faces from a larger distance.

I am dissapointed with so many OOF pictures. Of course I understand that the light conditions are completely different in the studio where the only source of it are the leading bulbs (set mostly on medium or high power). But the thing is that AF confirms with a beep and on actual pictures the focus is missing - often set on the bacground like on below NX Studio screenshot:

NX Studio shows that focus point is on face but actual focus is on the column in the background :-(

It seems that AF accuracy is better when shooting without flash even in low light conditions.

Have anyone experienced similar problems and know how to solve them?

I think your conclusions are wrong. I have been using the Z7 for over three years now and have zero problems with focus accuracy using a flash.

I don't know what that screen capture shows, but it does not show that you have eye detection and in fact, not even face detection. Also, you should set focus priority if you want high hit rate. With release priority the risks for pushing the shutter release too soon or too late is too high, especially if the subject is not static. So my own conclusion from your "problem" description is that this is simple user / camera configuration error.

Focus accuracy is just as good with flash as it is without a flash. If it is too dark and there is not enough contrast then the camera may struggle, but that's what the AF assist LED is used for, or you have to add some modelling light, but especially this picture should represent zero problems. Of course, there can be an issue with your camera, but it is very unlikely that you have identical issues with both the Z6 and the Z7 you claim to have, so I don't actually think that this is a camera error.

Yes, good remark !

OP also states in his post that AF confirms with a beep, so he is using AF-S ( no beeps when using AF-C ) . In OP's picture focus is achieved on the bright white background with the vertical lines IMO. That is exactly what Thom Hogan's warning is about when using AF area wide large/small modes in his Z6/7 e-guide.

--
Greetings,
Marc

 

[mrbr]

I started to use FF Z bodies early spring and I was very happy with both Z6 & Z7 including how AF performed during outdoors sessions - for mostly portraits, some fashion and street photos.

Now in late autumn I went back to the studio and I am using mainly external flashes radio trigerred remotely from the camera. It is Quadralite system. With such a setup I struggle a lot with the performance of my Z6&Z7 autofocus and I cannot figure out what is the reason?

The keepers ratio went down from about 90-95% of nicely sharp eyes during outdoor sessions to about 60% in the studio. I tried to compare Z6 and Z7 with two latest firmware versions 3.31 and 3.40. I was pretty restrictive with my judging - treating pictures as OOF whenever the focus slided visible towards the ears or nose instead of the eyes. I was using mainly AF-S, Auto-Area with eye detection but also single point AF. My keepers ratio was as follows:

In the EVF view both bodies performed substantially better with FW 3.40. The AF rectangles were stickier and recognized eyes and faces from a larger distance.

I am dissapointed with so many OOF pictures. Of course I understand that the light conditions are completely different in the studio where the only source of it are the leading bulbs (set mostly on medium or high power). But the thing is that AF confirms with a beep and on actual pictures the focus is missing - often set on the bacground like on below NX Studio screenshot:

NX Studio shows that focus point is on face but actual focus is on the column in the background :-(

It seems that AF accuracy is better when shooting without flash even in low light conditions.

Have anyone experienced similar problems and know how to solve them?

I think your conclusions are wrong. I have been using the Z7 for over three years now and have zero problems with focus accuracy using a flash.

I don't know what that screen capture shows, but it does not show that you have eye detection and in fact, not even face detection. Also, you should set focus priority if you want high hit rate. With release priority the risks for pushing the shutter release too soon or too late is too high, especially if the subject is not static. So my own conclusion from your "problem" description is that this is simple user / camera configuration error.

Focus accuracy is just as good with flash as it is without a flash. If it is too dark and there is not enough contrast then the camera may struggle, but that's what the AF assist LED is used for, or you have to add some modelling light, but especially this picture should represent zero problems. Of course, there can be an issue with your camera, but it is very unlikely that you have identical issues with both the Z6 and the Z7 you claim to have, so I don't actually think that this is a camera error.

Yes, good remark !

OP also states in his post that AF confirms with a beep, so he is using AF-S ( no beeps when using AF-C ) . In OP's picture focus is achieved on the bright white background with the vertical lines IMO. That is exactly what Thom Hogan's warning is about when using AF area wide large/small modes in his Z6/7 e-guide.

The picture in OP's example is shown at 100% , so shows only a small part of the picture.

Maybe OP is willing to post the original picture ? That could maybe help to understand better what the problem is.

--
Greetings,
Marc

 

[RazorSharpWO]

That's a D500. Red is the best for AF, after that it should be white. Blue is at the other end of the visible spectrum, so it should not be the best.

Actually, it's a d850. The camera used to take the photo was a d500 come up with the camera being photoed is the d850.

Interesting information. I'm traveling out-of-state right now, but I will post a photo of the actual set up, what the actual diffuser. I think it shoots white lights.

 

[Qbalion]

Here another example with AF eye detection confirmed and actual focus is somewhere on the ear. The model was static. I am not having any conclusions here. I am just trying to understand what (settings, operator mistakes, anything...) to change or to improve to make it better. I can send the full picture on priv if you want.

--
Our craft over our lenses over the camera bodies

 

[j_photo]

Presumably you are not talking about Z6/7 here as the firmware update does not add Wide Area Face/Eye detect according to posts here, and the Z5/Z6ii/7ii firmware was not updated significantly, so I don't think that's the issue in this thread.

Good point. When I started this project back in October of 2020, I was shooting with the Z7. My recollection back then is that focus was pretty good, but there were occasional misses, and I got in the habit of reviewing shots carefully during the shoot to make sure we were getting sharp results. I would say the hit rate was about the same as what I had previously experienced with my D800 in similar conditions. I was not experiencing any systemic issues, like some others are reporting here. Sometime later, I got the Z6 II and switched to shooting with that body. I think the Z6 II is more consistent.

Your point about firmware updates is right too. Thanks for clarifying that.

 

[Leonard Shepherd]

Yes, it locks nicely but the pictures are OOF. Like the one I inserted in OP.

If that image was a screen grab showing the focus area, you are not using eye-detect. You are illustrating Wide-area AF Large mode. In that mode the camera is not looking for eyes, But just anything within the red rectangle. You may get the nose or an ear, and at low apertures that means you won’t get a keeper.

Set AF-area mode to “Auto-area AF.”

Set Focus mode to Continuous AF (AF-C).

In custom setting a4 (original Z7), set to Face and eye detection ON.

Almost plus 1

AF does need detail with a reasonable amount of contrast parallel to the short dimension of the frame when not using AI to look for an eye.

If the studio lighting is very low relative to the flash exposure there may insufficient light for AF to lock on accurately before the flash operates.

When you point the camera at a person you will see a tiny rectangle on one eye, with an arrow pointing at the other eye. You can switch eyes by using the multi-selector.

This I find works extremely well

 

[j_photo]

Could you share more of your Af settings please? Was IBIS on?

Another poster has pointed out that some of the shooting experience I have been referring to was with the Z6 II, so not directly applicable to your situation. Early in the series of sessions that I was referring to I was shooting with the Z7. With that body, I was most confident relying on Dynamic Area, or occasionally single point, along with AF-C and back button focus. I was experiencing occasional focus misses, but nothing problematic. I was also experimenting with face/eye detect in Auto Area, but didn't like not having full control over where the focus point was landing. Sorry for any confusion I may have caused!

 

[olyflyer]

Here another example with AF eye detection confirmed and actual focus is somewhere on the ear. The model was static. I am not having any conclusions here. I am just trying to understand what (settings, operator mistakes, anything...) to change or to improve to make it better. I can send the full picture on priv if you want.

Ok. There are several things which can go wrong.

1. You move.

2. Subject moves.

3. You push the release too early.

4. You push the release too late.

5. You twist the focus ring accidentally.

None of that has with flash to do.

Disable the focus ring and enable focus priority. This will not give you 100% hit rate but probably will improve a lot. All of the above except 5 can happen even with focus priority, but will help you out.

... another question is... You did not do any focus tuning, did you? If you did then that might also cause a problem. Regardless what, the very low hit rate you get with TWO cameras indicates user error. I'm 99.99% sure that it's not camera or lens error and has nothing to do with flash.

 

[Boudewijn van der Drift]

Here another example with AF eye detection confirmed and actual focus is somewhere on the ear. The model was static. I am not having any conclusions here. I am just trying to understand what (settings, operator mistakes, anything...) to change or to improve to make it better. I can send the full picture on priv if you want.

Ok. There are several things which can go wrong.

1. You move.

2. Subject moves.

3. You push the release too early.

4. You push the release too late.

5. You twist the focus ring accidentally.

None of that has with flash to do.

Disable the focus ring and enable focus priority. This will not give you 100% hit rate but probably will improve a lot. All of the above except 5 can happen even with focus priority, but will help you out.

... another question is... You did not do any focus tuning, did you? If you did then that might also cause a problem. Regardless what, the very low hit rate you get with TWO cameras indicates user error. I'm 99.99% sure that it's not camera or lens error and has nothing to do with flash.

focus tuning is for DSLR's IMHO. ML has focus detection on the sensor. What is sharp on the sensor is sharp on the picture.

In DSLR's the focus detection is remote from the sensor, the different route may create focus error. And light metering error using (linear) polarizers.

P.S. looking at the picture, and understanding flash is involved, can the light have been too dim (prior to the flash) to perform AF?

 

[Boudewijn van der Drift]

OP I suggest a simple experiment in the situation of your last "eyes only" picture.

See if the camera AF's in the (dim) studiolighting, in your picture it did not.

Then turn up the lights, use an LEDpanel, torch anything, and see if the camera focuses that way.

If so, the remedy is, more studio lighting.

 

[Qbalion]

Ok. There are several things which can go wrong.

1. You move.

2. Subject moves.

Obvious reasons and theoretically can happen, but I am sensitive to be frozen and even holding my breath I believe, so not very probable. Just for testing purposes I'll try how AF-C changes the keepers ratio...

3. You push the release too early.

4. You push the release too late.

What do you really mean by too early or too late? I believe I push as soon as the focus is confirmed with AF-S, so with a static model it is a right moment. Too early would be corrected by focus priority - right?

5. You twist the focus ring accidentally.

I am convinced I do not even keep my left hand on the lens (usually primes) but on the body. Also I've just checked the ring needs to be turned pretty a lot to initiate manual focus. It is also visualized in the EVF with a focus slider so I would have notice. Nevertheless just in case I turned f2 from M/A to off.

None of that has with flash to do.

I understand there seems to be no correlation. With enough ambient light the AF should work the same way with or without flash. But please notice than in FW 3.40 release notes Nikon claims:

Improved face/eye detection performance and the visibility of subjects in pictures taken using an optional flash unit.

Disable the focus ring and enable focus priority.

It is on focus prio already

This will not give you 100% hit rate but probably will improve a lot. All of the above except 5 can happen even with focus priority, but will help you out.

... another question is... You did not do any focus tuning, did you?

AF fine tune is OFF.

If you did then that might also cause a problem. Regardless what, the very low hit rate you get with TWO cameras indicates user error.

I cannot figure out what changed my keepers ratio so badly since summer? My first guess was some FW 3.40 bug and that is why I rolled out back to 3.31 and compared results.

I'm 99.99% sure that it's not camera or lens error and has nothing to do with flash.

Lens were changed as well. Will keep trying...

 

[kssharma]

Ok. There are several things which can go wrong.

1. You move.

2. Subject moves.

Obvious reasons and theoretically can happen, but I am sensitive to be frozen and even holding my breath I believe, so not very probable. Just for testing purposes I'll try how AF-C changes the keepers ratio...

3. You push the release too early.

4. You push the release too late.

What do you really mean by too early or too late? I believe I push as soon as the focus is confirmed with AF-S, so with a static model it is a right moment. Too early would be corrected by focus priority - right?

5. You twist the focus ring accidentally.

I am convinced I do not even keep my left hand on the lens (usually primes) but on the body. Also I've just checked the ring needs to be turned pretty a lot to initiate manual focus. It is also visualized in the EVF with a focus slider so I would have notice. Nevertheless just in case I turned f2 from M/A to off.

None of that has with flash to do.

I understand there seems to be no correlation. With enough ambient light the AF should work the same way with or without flash. But please notice than in FW 3.40 release notes Nikon claims:

Improved face/eye detection performance and the visibility of subjects in pictures taken using an optional flash unit.

Disable the focus ring and enable focus priority.

It is on focus prio already

This will not give you 100% hit rate but probably will improve a lot. All of the above except 5 can happen even with focus priority, but will help you out.

... another question is... You did not do any focus tuning, did you?

AF fine tune is OFF.

If you did then that might also cause a problem. Regardless what, the very low hit rate you get with TWO cameras indicates user error.

I cannot figure out what changed my keepers ratio so badly since summer? My first guess was some FW 3.40 bug and that is why I rolled out back to 3.31 and compared results.

I'm 99.99% sure that it's not camera or lens error and has nothing to do with flash.

Lens were changed as well. Will keep trying...

This is EXACTLY what I am experiencing with my Z7II. I have tried with my 50 1.8 S and 24-70 2.8S. Same results.

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