Exposure issue with Nikon Z8

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BWP

BWP

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Hi folks,

I have a brand new Z8 and when I used it for the first time I experienced something unexpected. Here's how the camera was set up.

Manual mode with auto ISO selected. Maximum ISO set to 12800. The lens was a brand new 180-600 and was set to 600mm. Back focus was programmed. No exposure compensation. Bracketing was not enabled. Firmware is 2.0 Frame rate was set to 10 fps. The focus system was set to 3D. Metering was set to spot.

I was photographing ducks on a pond and every time I pressed the shutter release the first exposure was properly exposed on the first shot, but with each successive photo it became more and more over exposed. I tried this multiple times with the same result every time. After 4 or 5 frames the image was at least 3 stops over exposed.

This is extremely weird behavior which I have never seen before on any of my other Nikon cameras (D850, D810, D7200). Hopefully someone on this forum has seen this behavior and has a solution. If I have not provided enough information then please let me know and I'll add whatever info is needed to solve this.

Also, if anyone knows of a Nikon Z8 forum where I can post this question (outside of this one) I would appreciate it.

Cheers,
 
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Have you tried this in Matrix metering? I'm just wondering if while in Spot Metering your AF point is jumping around and with it the spot meter and sometimes hitting the background or elsewhere that might throw the metering off.

FWIW, I avoid spot metering action wildlife as it's so easy to slip the metering point off the subject and dramatically change exposure. It's typically fine for static subjects but mostly I use it for precise metering in full manual mode with manual ISO to set the ISO and then just shoot in that fixed setting until the light changes. It's nice to have precise metering for that but if there's any action and especially if my subject is small in the frame I avoid spot metering with auto exposure modes including auto ISO as small changes in the active AF point (due to focus tracking and subject detection) or poor panning on my part can dramatically change the metering and with it the exposure.
 
The interesting part is the op says it follows a pattern of progressive overexposure that they have repeated with the same result. What other than bracketing would give consistent results like that? I know on my Canon I can set the order of the bracket, middle out, darker to lighter or lighter to darker.
 
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BWP said:
Hi folks,

I have a brand new Z8 and when I used it for the first time I experienced something unexpected. Here's how the camera was set up.

Manual mode with auto ISO selected. Maximum ISO set to 12800. The lens was a brand new 180-600 and was set to 600mm. Back focus was programmed. No exposure compensation. Bracketing was not enabled. Firmware is 2.0 Frame rate was set to 10 fps. The focus system was set to 3D. Metering was set to spot.

I was photographing ducks on a pond and every time I pressed the shutter release the first exposure was properly exposed on the first shot, but with each successive photo it became more and more over exposed. I tried this multiple times with the same result every time. After 4 or 5 frames the image was at least 3 stops over exposed.

This is extremely weird behavior which I have never seen before on any of my other Nikon cameras (D850, D810, D7200). Hopefully someone on this forum has seen this behavior and has a solution. If I have not provided enough information then please let me know and I'll add whatever info is needed to solve this.

Also, if anyone knows of a Nikon Z8 forum where I can post this question (outside of this one) I would appreciate it.

Cheers,
Click to expand...
I wonder if this is a metering issue. Like @DRwyoming I don’t often use spot metering with wildlife photography.

To try to isolate the problem, save your current settings. Reset the camera to factory settings, then just turn on spot metering and auto ISO. Take a similar series of photos again. If you’re seeing the same behavior it’s because you’re moving the metering point a bit between frames to successively darker areas which will raise overall exposure accordingly.
 
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Thanks everyone for your quick responses. I just ran a test in the back yard and changed from spot to matrix metering and it worked fine. My guess is that the spot metering was the issue. Additionally, 3D was jumping around and if spot metering follows the focus point then this would explain the weird behavior. I'll test it in real life now and see how it works out. Again, thanks to everyone who responded.
 
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BWP said:
Thanks everyone for your quick responses. I just ran a test in the back yard and changed from spot to matrix metering and it worked fine. My guess is that the spot metering was the issue. Additionally, 3D was jumping around and if spot metering follows the focus point then this would explain the weird behavior. I'll test it in real life now and see how it works out. Again, thanks to everyone who responded.
Click to expand...
Yeah, the metering spot tracks the active focus point so when we run the mirrorless tracking modes and especially if we run a wider mode that active AF point can move around a lot and with it the metering spot. That's one big difference between this and the AF area modes most of us used with DSLRs.
 
DRwyoming said:
Yeah, the metering spot tracks the active focus point so when we run the mirrorless tracking modes and especially if we run a wider mode that active AF point can move around a lot and with it the metering spot. That's one big difference between this and the AF area modes most of us used with DSLRs.
Click to expand...

What would account for each successive exposure being more and more overexposed, as the op said. I would think the area under the focus point would be more or less random as it metered sometimes darker sometimes lighter areas?
 
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bleirer said:
What would account for each successive exposure being more and more overexposed, as the op said. I would think the area under the focus point would be more or less random as it metered sometimes darker sometimes lighter areas?
Click to expand...
From the description I'd say this wasn't rigorous and repeatable lab testing but an observation out in the field of how exposure changed when shooting ducks on a pond. Maybe it followed an exact sequence of exposure changes and maybe it did that more than once or with different subjects and scenes but it's really hard to guess without seeing and evaluating the images.

Yup, if the exposure literally changed in an exact and repeatable pattern in a variety of situations, that would be strange but I wouldn't take that too literally without seeing and evaluating the images.

What I do know is what you quoted that Nikon's spot meter point follows the active AF point and when running in an auto AF tracking mode that means the spot metering point can jump around quite a bit and not be exactly where we think it should be. When running in an auto exposure mode that can lead to big exposure changes from frame to frame especially if the AF acquisition struggles a bit on smaller subjects or in low contrast situations. I believe other manufacturers fix the spot metering to the center AF point but that's not the way Nikon has handled it in modern cameras with multiple AF points across the frame.
 
Just an aside, but Canon weights the confirmed focus point only in evaluative (matrix) mode. Spot metering it does only at the center, as mentioned above.

I'd have to assume that even in matrix Nikon would weight the confirmed focus point also, making it a good choice for the OP.
 
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