Spot Metering changes ISO in a burst on Z9

[Butlerkid]

unless the subject or background change. In this case the beating of the wings may give a different exposure. Or the background could change when as the bird moves around the scene (probably not here)

Obviously if the subject or background change the photographer should decide whether or not to change his settings.

 

[Calson]

Another possibility is that the lens is not always able to stop down to the correct aperture from its wide open position during a burst of shots. I would try a different lens to verify one way or another whether this is the case.

 

[ARClark]

I think it might be behaving like that because the area that the AF point is on is relatively dark (especially if the head of the bird is close enough to the AF point to be factored into the metering calculation). It appears that in the second shot the camera has lightened the body of the bird more towards middle gray.

I agree. I use spot metering with 3D AF and subject detection a lot when shooting birds, and I encounter this all the time. It's especially impactful when shooting birds with black eyes or black around the eyes like chickadees, cardinals, and Eastern towhees. With any subtle changes in the AF point through camera and/or subject movement, the spot metering will adjust and ISO will change, sometimes from shot to shot, as the AF zeros in on the dark subject. To avoid this, one could shoot in a different exposure mode, or if I recall, spot metering can be disengaged from subject detection. I've also used exposure compensation at times to counter the extreme spot meter adjustments.

 

[MartyD]

This is a long shot.....

I received my Z9 on a Friday and shot a football game on Saturday afternoon. I was shooting manual with auto ISO and I was having some strange exposure variations. What I found was that setting b2: Matrix Metering Face Detection was set to on. If the Z9 found the face of a football player it tried to expose for the face, it didn't matter if the face was covered with a tinted face shield it tried to expose for the face. There was a huge exposure variation.

I know you were shooting in spot metering and I don't believe this setting applies to spot metering, I'm just wondering if in some of the frames the camera metered for something it detected in those frames that it did not detect in the other frames. If subject detection was on, what mode was it in, Auto, People, Animal?

 

[EricKlees]

I shoot exclusively in full manual in either matrix 95% is the time and highlight weighed meter the other 5% of the time. I tried using spot meter in auto iso a couple months ago with my Z9+800PF. I was getting some crazy exposure adjustments and have up on it after 2 burst sequences of balls takes.

I just leave nothing for the camera to control as it can get fooled far to easily. Plus with real time exposure in the EVF, i have no clue why anyone shots in Auto ISO anymore, especially if you have a Z lens with a control ring to set it for ISO control.

 

[Butlerkid]

I shoot exclusively in full manual in either matrix 95% is the time and highlight weighed meter the other 5% of the time. I tried using spot meter in auto iso a couple months ago with my Z9+800PF. I was getting some crazy exposure adjustments and have up on it after 2 burst sequences of balls takes.

I just leave nothing for the camera to control as it can get fooled far to easily. Plus with real time exposure in the EVF, i have no clue why anyone shots in Auto ISO anymore, especially if you have a Z lens with a control ring to set it for ISO control.

.....maybe because panning a flying bird or fast moving subjects with varying backgrounds you simply don't have time to adjust exposure...............................

 

[arbitrage]

Plus with real time exposure in the EVF, i have no clue why anyone shots in Auto ISO anymore, especially if you have a Z lens with a control ring to set it for ISO control.

I wonder this every single day when all I read about is Auto-ISO this, Auto-ISO that. I read people talk about it so often that I feel I must have missed something so then I go back and use it for a day and I realize I haven't missed anything...with MILC WYSIWYG it makes no sense and just ruins exposures during any type of flight sequence as size of subject in frame and backgrounds change.
With Canon and Sony I have 3 wheels on the body to control my variables...with Nikon I used the control ring to change ISO. Everything is under your control and most of the time the light on the subject isn't changing so you don't have to change anything.
Using Spot metering just takes using a semi-auto mode to a whole other level of headache....I don't see why anyone would put themselves through that.

 

[arbitrage]

.....maybe because panning a flying bird or fast moving subjects with varying backgrounds you simply don't have time to adjust exposure...............................

That is the number one situation where using Auto-ISO is going to ruin your exposure....using full M would give you a perfect exposure for every frame no matter what the background is and no matter how large the subject is in the frame.

If the light is changing on the subject during the flight sequence AND the background isn't changing AND the subject isn't changing size in the frame THEN M+AutoISO would work better than full M. But how often is that the case? Even if the light is changing on the subject, the background and size in the frame is likely also changing so you are basically going to ruin some exposures no matter what mode you are shooting. Better to use Full M, expose for the subject in the bright light, let the camera underexpose when the subject is in shade and use the built in ISO-less sensor to raise brightness in post which would get you the same result you'd get if the Auto-ISO raised the ISO properly anyways (which it probably won't half the time). As long as your missed exposures are due to too low and ISO (underexposed) then you are safe and you can control that in Full M. Using Auto-ISO risks missed exposures with too high an ISO (overexposed) and then you can't recover.

 

[DRwyoming]

Using Spot metering just takes using a semi-auto mode to a whole other level of headache...

Agreed.

To me, spot metering can make sense when you want very precise control over what small part of the image is used for metering. But at least with Nikon where the spot metering point tracks the active AF point you're basically losing that precise control when running in any form of subject detection along with an auto exposure mode and especially when running in 3D or Auto AF Area mode. You're basically giving the camera control of what small portion of the overall frame is used for metering and that depends on what the subject detection algorithms manage to detect.

It makes no sense to me to run in a precise metering mode and then give control of that precise metering location to an automated AF system that can and does change where that spot metering point is located within the frame.

Take a white bird with dark eyes at a range where the eyes could take up a large portion of the relatively small spot metering area. With subject/eye detection enabled the AF system could initially achieve subject detection and the spot metering area would be on something like the white breast or wing feathers. But a moment or even a frame later the detection algorithms might successfully detect the eye and now the spot metering area is on the dark eye. In an automated exposure mode the camera exposure settings could easily change by three or four stops between images in that situation.

Spot metering to set a full manual exposure (e.g. metering on a neutral tone area like green grass lit by the same light as anticipated subjects) can make a ton of sense but running with both automated exposure and automated focus point selection while spot metering doesn't make much sense to me.

 

[bleirer]

Just curious about this camera, does it need to be set in the menu to meter at the confirmed focus point? If it doesn't confirm focus does it meter at the position of the focus point anyway? I ask because Canon in spot metering only uses the center location and the only other way to weigh the meter to the focus point is to use evaluative (matrix) metering.

Overall I would think spot would not be a good choice for this situation anyway. To me the purpose of spot is to study the scene to see the relationships between the lights and darks of the scene in the overall light falling on the subjects. That is more contemplative for when you have time to really think through exposure, not when things are happening fast and furious.

 

[SoCalRick]

Just curious about this camera, does it need to be set in the menu to meter at the confirmed focus point? If it doesn't confirm focus does it meter at the position of the focus point anyway? I ask because Canon in spot metering only uses the center location and the only other way to weigh the meter to the focus point is to use evaluative (matrix) metering.

When using Single-point AF along with Spot Metering, the location used for metering occurs at the center of the focus point. IDK if it makes any difference if the camera locks focus, or not. (I would venture a guess that it doesn't)

Additionally, the size of the metering area is reported to be (much) larger than the Single-point cursor that is depicted. Thom has stated that the spot metering area is a little more than three times the height and width of the Single-point AF cursor.