2 serious bugs with 3D tracking and metering

Started Dec 1, 2007 | Discussions
OP jp Senior Member • Posts: 1,151
Ok, here is an example

KennyKB wrote:

jp,

just out of curiosity, how do you know matrix is not following the
initially selected AF point? I don't have a D300 yet so excuse my
ignorance if the answer is obvious.

Please don't worry Kenny, there are no stupid questions, only stupid answers, and I usually try to avoid giving those unless people start to get nasty because they can not stand criticism of their gear.
To make the simplest example:

take a scene with on the left and right a dark part and in the middle a gright part
Position the af point in the middle and meter (over the dark part)

Do not change framing but place the AF spot (on a side AF point over the bright part)
The two situations wil meter exactely the same in 3D tracking mode.

If you do the same but without 3D tracking mode, the metering changes to reflect the subject brighness under the AF point.

It does not matter what other mode you use (AF-C, AF-S combined with dynamic AF or single AF, it always works correctly, except in AF-C mode with dynamic 3D tracking.

Hope this makes things clearer for you and anyone else who did not get the whole picture of this probable issue.

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rondv Contributing Member • Posts: 585
Re: 2 serious bugs with 3D tracking and metering

jp wrote:

Did you have 3d tracking enabled, AF-C selected and used another AF
point than the center one?
And how did you perform the test?

http://forums.dpreview.com/forums/read.asp?forum=1039&message=25861556

Yes. That information is in the post above. I also chose a focus point to the far left of the viewfinder and locked onto the lower edge of a roof line in the shadows and tracked up and as the focus points move and the scene became brighter the exposure did change.

Again, how did you determine there is bugs in the tracking and exposure of the camera?

Rickard Hansson Senior Member • Posts: 2,082
Re: Domain is a good idea

Ahh, c´mon. Just file a complaint directly to nikon then.

Thn they will get the information directly from you.

You can even do it online from their support pages if you like that instead of phoning/calling them.

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Rickard Hansson
Sweden

OP jp Senior Member • Posts: 1,151
Re: 2 serious bugs with 3D tracking and metering

rondv wrote:

jp wrote:

Did you have 3d tracking enabled, AF-C selected and used another AF
point than the center one?
And how did you perform the test?

Again, how did you determine there is bugs in the tracking and
exposure of the camera?

http://forums.dpreview.com/forums/read.asp?forum=1039&message=25869774

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SBedard New Member • Posts: 15
Re: Ok, here is an example

Sorry if I ask the same question others asked already, but I can't seem to reproduce the problem. Here's the setup. camera at matrix metering, single point focus selected, AF-S,and shooting Menu A3 set to 51 points 3d tracking. I framed a scene with some bright and dark areas, then half pressed the shutter. Then, while keeping the shutter half pressed, I moved the focus point around , and, as the subjects on the focus points changed from bright to dark, as did the exposure. I changed accordingly... Did I misunderstood the way to setup or test ?

Just in case, my firmware versions are A;1.01, B: 1.00

Thanks

Step Bed

rondv Contributing Member • Posts: 585
Re: 2 serious bugs with 3D tracking and metering

jp wrote:

rondv wrote:

jp wrote:

Did you have 3d tracking enabled, AF-C selected and used another AF
point than the center one?
And how did you perform the test?

Again, how did you determine there is bugs in the tracking and
exposure of the camera?

http://forums.dpreview.com/forums/read.asp?forum=1039&message=25869774

jp your test is flawed or your camera. I tracked a bird with the sky as the background and as it flew in front of some trees the camera continued to track and the exposure changed. AF-C, dynamic area, 51 pt 3d tracking. It works in both manual and av mode and all metering modes.

Tony H Regular Member • Posts: 430
Re: Ok, here is an example

Hi,

Now, I'm not sure here, I don't have my D300 yet, but it seems to me - by my reading, and in my VERY humble opinion, that the test may be flawed - mostly because the way I understand what you are describing you are not "tracking" an object, you are manually changing a focus point with the shutter at 1/2 press.

It is possible that in 3D Tracking mode - it is meant for tracking, where the camera tracks and object? perhaps it is not designed to function the way you are using it manually moving a focus point rather then letting the camera track the subject?

like I said, I don't really know, I'm just thinking about the wording for the mode the camera is in, and I guess I would assume that in 3D Tracking, the camera would be responsible for doing the tracking as long as the shutter is 1/2 press? And although you manually moved the focus point, the camera did not track the subject of original interest to the new location, so the camera did not re-meter the total image?

Just a thought - like I said, I'm shooting from the hip here from what I interpreted from the posts, other peoples responses and the bits of the manual I have read so far waiting for my camera.

-T

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chorrell Regular Member • Posts: 179
NOT a problem - solution is easy

There is a very simple solution. Set C1 to ON and exposure remains locked on the original subject while tracking still works.

If you want to recompose, let go of the shutter and press again.

Regards,
Craig.

OP jp Senior Member • Posts: 1,151
Re: 2 serious bugs with 3D tracking and metering

rondv wrote:

jp your test is flawed or your camera. I tracked a bird with the sky
as the background and as it flew in front of some trees the camera
continued to track and the exposure changed. AF-C, dynamic area, 51
pt 3d tracking. It works in both manual and av mode and all metering
modes.

The fact that exposure changes should not be interpreted as correct exposure metering.

If the scene changes, then exposure changes but this dos not mean that exposure is correct
You must use a static scene and switch AF points to simulate problem #1

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OP jp Senior Member • Posts: 1,151
Yes but

chorrell wrote:

There is a very simple solution. Set C1 to ON and exposure remains
locked on the original subject while tracking still works.

If you want to recompose, let go of the shutter and press again.

Regards,
Craig.

That was the workaround I suggested in my OP but remember to switch it of when you use auto area af in af-s mode because there it first locks exposure and then determines the AF point which is also incorrect: it should be the other way round. C1 off works correct however

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OP jp Senior Member • Posts: 1,151
My test is not flawed

Tony H wrote:

Hi,

It is possible that in 3D Tracking mode - it is meant for tracking,
where the camera tracks and object? perhaps it is not designed to
function the way you are using it manually moving a focus point
rather then letting the camera track the subject?

The exposure should always be based on the manually selected point not on the center point. That is the error I am talking about

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rondv Contributing Member • Posts: 585
Re: 2 serious bugs with 3D tracking and metering

jp wrote:

rondv wrote:

jp your test is flawed or your camera. I tracked a bird with the sky
as the background and as it flew in front of some trees the camera
continued to track and the exposure changed. AF-C, dynamic area, 51
pt 3d tracking. It works in both manual and av mode and all metering
modes.

The fact that exposure changes should not be interpreted as correct
exposure metering.
If the scene changes, then exposure changes but this dos not mean
that exposure is correct
You must use a static scene and switch AF points to simulate problem #1

http://forums.dpreview.com/forums/read.asp?forum=1039&message=25857992

I did that jp and the exposure changed with the focus point. Whats the point in shooting a static scene in 3d tracking? Now you're stating the exposure does change but is not correct. Why do you think the camera would not give the proper exposure as the focus point and light changes?

jp wrote:

1) If you use ASF-C with 3D tracking then the metering (spot/matrix)
always supposes that the subject is in the middle of the frame
instead of under the selected AF point.
2) As the AF point tracks across the screen, the metering does not
follow the AF point

Now you're changing what you originally posted. I'm not trying to argue with you but you did make the post and I can find no evidence nor did you give any of the problem (?) you stated.

Jim Keye Senior Member • Posts: 2,195
AF-C

According to the OP/thread, you have to be in AF-C for the bug to appear, not AF-S.

SBedard New Member • Posts: 15
Re: AF-C

Oups...Sorry, but actually, I WAS on AF-C...just a typo...So, back to the start. My exposure DOES change as I change the focus point manually.

Steph Bed

Jim Keye Senior Member • Posts: 2,195
Re: Yes but

jp wrote:

chorrell wrote:

There is a very simple solution. Set C1 to ON and exposure remains
locked on the original subject while tracking still works.

If you want to recompose, let go of the shutter and press again.

Regards,
Craig.

That was the workaround I suggested in my OP but remember to switch
it of when you use auto area af in af-s mode because there it first
locks exposure and then determines the AF point which is also
incorrect: it should be the other way round. C1 off works correct
however

JP, thank you for this thread, it's been interesting. I don't mean the following to sound insulting. I really don't. But: who heck lets the camera choose the AF point? (auto area af in af-s)? I can see closest-subject in some caes as always being right, but that has limits to.

So two questions:
1) What is "auto AF"? (is this a rename of "closest-subject?")
2) When do you anticipate using it?

SBedard New Member • Posts: 15
Re: 2 serious bugs with 3D tracking and metering

I agree with Rondv. I did the static scene setup and seems to be fine. Here's the setup. camera at matrix metering, single point focus selected, AF-C,and shooting Menu A3 set to 51 points 3d tracking. I framed a scene with some bright and dark areas, then half pressed the shutter. Then, while keeping the shutter half pressed, I moved the focus point around , and, as the subjects on the focus points changed from bright to dark, as did the exposure. I changed accordingly... Did I misunderstood the way to setup or test ?

Just in case, my firmware versions are A;1.01, B: 1.00

steph Bed

Jim Keye Senior Member • Posts: 2,195
Also

jp wrote:

chorrell wrote:

There is a very simple solution. Set C1 to ON and exposure remains
locked on the original subject while tracking still works.

If you want to recompose, let go of the shutter and press again.

Regards,
Craig.

That was the workaround I suggested in my OP but remember to switch
it of when you use auto area af in af-s mode because there it first
locks exposure and then determines the AF point which is also
incorrect: it should be the other way round. C1 off works correct
however

I want to make sure I'm understanding this: with AF-C/3D tracking:

-matrix metering seems to only use the center spot, doesn't change weighting based on selected AF point
-with spot metering, the initial exposure does change based on selected AF point

-with neither system does the exposure seem to change as the framing or AF points change, IOW once the AF is working and tracking is taking place?

C1 would supposedly eliminate the problem with spot metering because it would track the "subject" for exposure. C1 would have the same effect for matrix, only that it might not be the right exposure in the first place?

Am I getting all this correct? Thanks.

rondv Contributing Member • Posts: 585
Re: 2 serious bugs with 3D tracking and metering

SBedard wrote:

I agree with Rondv. I did the static scene setup and seems to be
fine. Here's the setup. camera at matrix metering, single point focus
selected, AF-C,and shooting Menu A3 set to 51 points 3d tracking. I
framed a scene with some bright and dark areas, then half pressed the
shutter. Then, while keeping the shutter half pressed, I moved the
focus point around , and, as the subjects on the focus points changed
from bright to dark, as did the exposure. I changed accordingly...
Did I misunderstood the way to setup or test ?

Just in case, my firmware versions are A;1.01, B: 1.00

steph Bed

I think you understand well. My first thought was that I didn't understand how he came to the conclusion that the metering was flawed so I checked tracking and metering on static and moving objects where the light changed and the meter responded to the selected focus point and not the center one. His replies are a contradiction to his OP. His test or his camera is flawed.

Tony H Regular Member • Posts: 430
Re: My test is not flawed

Not as I see it when you are manually moving a focus point while 1/2 pressed on teh shutter, you are attempting to override the tracking of the camera.

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Peter Davis Senior Member • Posts: 1,171
Re: 2 serious bugs with 3D tracking and metering

Like the others, I am not seeing the problem here. I set AF-C, 3D tracking, Spot metering. Move the focus point to the side of the frame. Put a bright object under the focus point, and a dark one under the center point. Observe metering is correct.

So no matter which mode you're in, IT IS METERING ON THE (INITIALLY) MANUALLY SELECTED FOCUS POINT. IT NEVER METERS ON THE CENTER POINT (UNLESS YOU SELECTED IT)!

Now I agree it's annoying that the metering point doesn't track along with 3D tracking, and I wish it did, but at least it's no worse than the other dynamic AF modes (on D200 or D300), for which metering did not track either.

What's the bug again?

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