Another strange bug with D4, possibly D800!?!?

Started Feb 5, 2013 | Discussions
michaeladawson Forum Pro • Posts: 12,507
'lock' called it

Roland Schulz wrote:

I can reproduce your problem with the D800 but not the D4. My D4 has the latest firmware that was released last week. 1.04? I tried this morning moving from indoor light to outdoor light through a window. With AF lock held the indicated exposure changes as I swing the camera from indoor to outdoor light. When I let go of the lock button the indicated exposure stays steady and it is the correct exposure.

On the D800 I can't set the AF-ON button, but I can assign the AE/AF lock button to be AF Lock Only. So I did that and repeated the test. Indoors I focused on something. Indicated exposure was f/4 at 1/15s. I pressed and held the assigned AF Lock button and swung the camera outdoors. The exposure changed to f/4 at 1/60s. But this is way overexposed if I trip the shutter now. If I release the AF lock button (holding the AF point steady over the same target the exposure jumps to something like f/4 at 1/400s. This is the correct exposure.

Interesting: Your D800 behaviour is exactly what my D4 shows, why doesn´t your D4 show the same?! Nikon Germany can also verify the problem.
I wonder why your D4 works??? Be happy it does, but for me the described workaround is fine so far.

Thanks,
Roland.

OK... I can reproduce your D4 experience.

Thank you 'lock' for specifically calling out the metering mode.  I shoot in center weighted mode a lot of the time.  And in fact, when I ran the tests on Tuesday and Wednesday my D4 was in center weighted mode.  My D800 was in matrix metering mode.

So tonight I switched the D4 to matrix metering.  Lo and behold.... same behavior as my D800 and that reported by Roland.

-- hide signature --

Mike Dawson

 michaeladawson's gear list:michaeladawson's gear list
Nikon D810 Nikon D7200 Nikon D5 Fujifilm X-T2 Fujifilm X-H1 +28 more
Marianne Oelund Veteran Member • Posts: 7,353
It is by design for matrix metering
1

Roland Schulz wrote:

I see that exposure changes while recomposing, but it´s not the right exposure since when I let the AF-ON button off the exposure changes significantly (may change about 5 stops under certain circumstances)! That´s is not the wanted behaviour and it´s also not found in the manual.

Anyone else found this? Maybe also on D800?

Roland.

It isn't a bug; it's a feature of the matrix metering system.

The central assumption is that when you perform the initial focusing, the exposure there is valid for your intended subject.  If, when you recompose, the exposure changes dramatically, the camera assumes that most of that change is due to portions of the scene that are not the intended subject.  Thus it limits the amount that it allows the exposure to change from where you had the camera pointed for focusing.

This is only one of many operational details that Nikon omit from their elementary-level manuals.  I keep hoping that they will make advanced versions of the manuals available, which discuss these fine points.  Professional users, at least, certainly deserve better.

-- hide signature --

Qualities possessed by God in infinite proportion: Love, Grace, Power, Righteousness, Wisdom, . . .
Qualities possessed by humans in infinite proportion: Ignorance.
- Marianne

lock Veteran Member • Posts: 6,202
The undocumented 'features'

Something Nikon has plenty of... We could rewrite the manual if we collected all the knowledge.

hendrikm2 Regular Member • Posts: 209
Solution and Explanation

Dear Roland,

as Marianne already described, this behaviour is NORMAL. It´s not a bug but an intrinsic feature of the Matrix metering. I confirmed this with my D800.

Here´s a quote from the D800 manual:

Verwenden Sie den Belichtungs-Messwertspeicher, um den
Bildausschnitt nach der Belichtungsmessung mit der mittenbetonten
Messung und der Spotmessung neu zu wählen. Beachten Sie, dass die
Matrixmessung nicht die gewünschten Ergebnisse erzielt.

Sorry for quoting in German, these are the first few lines of the chapter about AE-L/AF-L and they state that if you use Matrix and exposure (or focus) lock, the results are not as expected.

Solution: Use centerweighted or spot metering. Matrix was NEVER intended to be used with focus/recompose or other techniqes which involve changing the field of view, as you do with your AF-lock.

OP Roland Schulz Contributing Member • Posts: 716
Re: It is by design for matrix metering

It isn't a bug; it's a feature of the matrix metering system.

The central assumption is that when you perform the initial focusing, the exposure there is valid for your intended subject. If, when you recompose, the exposure changes dramatically, the camera assumes that most of that change is due to portions of the scene that are not the intended subject. Thus it limits the amount that it allows the exposure to change from where you had the camera pointed for focusing.

This is only one of many operational details that Nikon omit from their elementary-level manuals. I keep hoping that they will make advanced versions of the manuals available, which discuss these fine points. Professional users, at least, certainly deserve better.

Hi Marianne,

thanks for your description. Interestingly Nikon Germany themself don´t know about this "feature" (ok, that means nothing), here what they responed to me:

Sehr geehrter Herr Schulz,
vielen Dank für Ihre Anfrage bezüglich der D4.
Wir konnten das von Ihnen angetroffene Verhalten nachstellen, sind ebenfalls über die Ergebnisse verwundert. Wir haben Ihre Anfrage aus diesem Grund, zwecks weitere Untersuchung, an eine höhere Abteilung weitergeleitet.
Sobald wir eine Rückmeldung der Kollegen erhalten haben, werden wir sofort wieder mit Ihnen in Kontakt treten, können bis wir dieser erhalten haben jedoch leider nicht direkt antworten, sollten Sie Ihre Anfrage aktualisiert haben.
Ich hoffe ich handele in Ihrem Sinne und verbleibe mit freundlichen Grüßen,
xxxx xxxx
Nikon Europe Support

means: they can verify the behaviour but don´t know why that happens ;-)! They check back with other people and come back to answear later!

Ok, my opinion and persuasion is still that this is a bug cause

a) I don´t find any documentation or hint to this under chapter a8 in the user manual, no footnote, nothing.
This needs not have to do with general matrix metering and again, the function is defined as "AF lock ONLY". I only (want to) freeze the distance the AF measures, I want nothing more, nothing more is described, hinted or documented under chapter a8 or the chapter itself.

b) I find the described function or feature (from you and "lock") of VERY limited to none sense. The camera can not know or measure if the point under the AF sensor from pressing the AF-ON is still in the frame, even hardly to not with the 92.000 dot matrix metering system. 
Sometimes I sample a distance and turn completely around in another direction. The measured point/exposure is nowhere in the frame any more, but is in calculation for the new frame -> silly,  no sense just nonsense.
Sampling a distance is of sense if you cope with DOF calculations and have no known reference to focus on in the frame you want to take. You take the reference from somewhere else and freeze that focus. I often do that.

c) what sense makes a "feature" that gives you "unexpected" results??
This (resulting exposure) seems/is not random, but what is an exposure of a focused subject after swiveling to a maybe complete different lightning in the frame? The exposure is lifted or lowered to some degree between scene A and B. It´s somewhat exposure compensated, but is that the wanted result? No algorithm can know. Therefore we have matrix metering and manual exposure compensation! The result now is hard to be foreseen.

Seems that this happened with many Nikon cameras before, I haven´t recognized till now. For me, time to stop with this, no sense in my eyes, but there may be others...

Ok, I look forward to what Nikon will tell me. I already found a fine workaround for this as described above here: http://forums.dpreview.com/forums/post/50807179

Roland.

 Roland Schulz's gear list:Roland Schulz's gear list
Nikon D3 Sony a6500
jdhill66 New Member • Posts: 9
Re: It is by design for matrix metering
1

I think there's another element that is confusing this discussion. It appears that holding the AF-ON button is not what "locks" the focus. It becomes locked when the AF-ON button is RELEASED. Holding it in means that focus can still be changing, as is obvious when in AF-C mode. And in Matrix mode, holding AF-ON in also lets the metering change to some degree. Releasing the AF-ON button lets the metereing adjust fully. On my D800 the only place I see the change in metering from holding to releaasing the AF button is the combination of AF-S and Matrix. All other combinations show no change in exposure between hold and release.

Peter Damroth Contributing Member • Posts: 652
Re: Another strange bug with D4, possibly D800!?!?

Roland Schulz wrote:

Hi there,

today I found the following with my D4: Most times I´m using AF-C and so configured the AF-ON button to AF hold using custom function a8.

So I can focus the camera with the shutter pressed to the first step (continous), and if I like to hold focus to recompose I hold the AF-ON button to save the prefocused distance. So far so good, focus is held, but exposure should be independent to this (have AE-L to switch with the middle of the sub dial, f6).

I see that exposure changes while recomposing, but it´s not the right exposure since when I let the AF-ON button off the exposure changes significantly (may change about 5 stops under certain circumstances)! That´s is not the wanted behaviour and it´s also not found in the manual.

Anyone else found this? Maybe also on D800?

Roland.

Are you set on spot metering?

-- hide signature --

Peter Damroth Photography

 Peter Damroth's gear list:Peter Damroth's gear list
Kodak DCS Pro SLR/n Nikon D300 Nikon D600 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S DX Nikkor 16-85mm f/3.5-5.6G ED VR +14 more
jeminijoseph Veteran Member • Posts: 6,486
Re: try this

Roland Schulz wrote:

After focusing release af-on button and hold the shutter release button. That will keep your exposure. This means both your thumb and fore finger is always working.

That´s totally different from what I want. I want to keep focus, NOT exposure.

Not sure if I understood your requirement. Anyway hope others will be able to answer you. I use AF-C 100% of time on my D4 and it works perfectly. Anyhow I shoot only wildlife. I change the focus point using the joy stick and focus and shoot. I leave the exposure to the camera. If I shoot dark scenes I put exposure compensation. sometimes I have to adjust expsoure in post processing because camera expose to the technical perfection. It doesn't know my artistic needs.

 jeminijoseph's gear list:jeminijoseph's gear list
Nikon D500
OP Roland Schulz Contributing Member • Posts: 716
Re: Another strange bug with D4, possibly D800!?!?

Peter Damroth wrote:

Roland Schulz wrote:

Hi there,

today I found the following with my D4: Most times I´m using AF-C and so configured the AF-ON button to AF hold using custom function a8.

So I can focus the camera with the shutter pressed to the first step (continous), and if I like to hold focus to recompose I hold the AF-ON button to save the prefocused distance. So far so good, focus is held, but exposure should be independent to this (have AE-L to switch with the middle of the sub dial, f6).

I see that exposure changes while recomposing, but it´s not the right exposure since when I let the AF-ON button off the exposure changes significantly (may change about 5 stops under certain circumstances)! That´s is not the wanted behaviour and it´s also not found in the manual.

Anyone else found this? Maybe also on D800?

Roland.

Are you set on spot metering?



No, matrix metering.

 Roland Schulz's gear list:Roland Schulz's gear list
Nikon D3 Sony a6500
OP Roland Schulz Contributing Member • Posts: 716
Re: It is by design for matrix metering

jdhill66 wrote:

I think there's another element that is confusing this discussion. It appears that holding the AF-ON button is not what "locks" the focus. It becomes locked when the AF-ON button is RELEASED. Holding it in means that focus can still be changing, as is obvious when in AF-C mode. And in Matrix mode, holding AF-ON in also lets the metering change to some degree. Releasing the AF-ON button lets the metereing adjust fully. On my D800 the only place I see the change in metering from holding to releaasing the AF button is the combination of AF-S and Matrix. All other combinations show no change in exposure between hold and release.











No, in the described setup focus is frozen when AF-ON is held.

 Roland Schulz's gear list:Roland Schulz's gear list
Nikon D3 Sony a6500
ssmumich00 Regular Member • Posts: 417
Re: Another strange bug with D4, possibly D800!?!?

Roland Schulz wrote:

Hi there,

today I found the following with my D4: Most times I´m using AF-C and so configured the AF-ON button to AF hold using custom function a8.

So I can focus the camera with the shutter pressed to the first step (continous), and if I like to hold focus to recompose I hold the AF-ON button to save the prefocused distance. So far so good, focus is held, but exposure should be independent to this (have AE-L to switch with the middle of the sub dial, f6).

I see that exposure changes while recomposing, but it´s not the right exposure since when I let the AF-ON button off the exposure changes significantly (may change about 5 stops under certain circumstances)! That´s is not the wanted behaviour and it´s also not found in the manual.

Anyone else found this? Maybe also on D800?

Roland.

I think the recent firmware addressed AF-C related issues like this, no?

-- hide signature --

(w): www.neilphotos.com
(p): www.suneil.net

 ssmumich00's gear list:ssmumich00's gear list
Nikon D7000 Nikon AF-S Nikkor 24-70mm f/2.8G ED Nikon AF-S Nikkor 50mm f/1.4G Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II Nikon AF Nikkor 20mm f/2.8D +3 more
jdhill66 New Member • Posts: 9
Re: It is by design for matrix metering

Focus is frozen if in AF-S mode, but if in AF-C mode, focus will keep adjusting until the AF-ON is released.

lock Veteran Member • Posts: 6,202
No.

Not with a8 set to the last item. With a8 on the first item , you are correct.

lock Veteran Member • Posts: 6,202
No, it did not

As I explained by Oelund and me (halfway the discussion) this behavior is as intended by Nikon.

OP Roland Schulz Contributing Member • Posts: 716
Re: No.

lock wrote:

Not with a8 set to the last item. With a8 on the first item , you are correct.

Totally right!!

 Roland Schulz's gear list:Roland Schulz's gear list
Nikon D3 Sony a6500
lock Veteran Member • Posts: 6,202
Just a small story, Roland

When I first complained about the changes in the D600/D800/D4 behavior concerning AF-on and focus priority, I had to explain on the telehone the most experienced guy of Nikon Netherlands (van Stijn, well known here) what was actually different compared to the D700/d300/d3/d3s/d3x and the d7000. Once he saw what was going on (as many others did here on the forum) he simply stated 'Ooh, it must be designed that way'. He did not even bother to verify this with Nikon Japan. But on this forum several confirmations about the intentional change in functionality can be found, so he was right.
So you should not be too suprized if in Germany the Nikon staff does not understand what is going on wth a D4. Things are getting complicated even for them. Heck, even in Japan the cannot clearly explain how it works (just read the manual and you know what I mean).

lock

Keyboard shortcuts:
FForum MMy threads