Center Weight Metering

I think I understand the other 2 metering modes (matrix and spot) that my d90 can do well enough. But I'm trying to envision a scenario where center-weight metering would be used. It seems like a hybrid between matrix and spot and therefore why not just pick whichever of those two the situation is closest to? Am I missing something or is this just a seldom used mode?

I use center-weight all the time... Spot is too focused and limiting many times, and matrix is too broad...

Spot can really cause some major problems depending on the spot you pick. Pick a white spot and it will try to make it 18% grey so the rest of the photo will be underexposed. Pick a black spot and everything will be overexposed.

Matrix can cause problems also. Family in the nice shade and you have a bright sky. Matrix will take into account the bright sky and will underexpose the family in the shade.

Center-Weighted is a good all-around mode since it is going to expose for the area that you are really shooting, The family in the shade.

There are times where the other two modes are needed but Center-Weighted is the one you should default to most of the time.

Center-weighted meters the same area as matrix but gives priority to the middle area. You would want to use it when the subject fills a significant part of the view but still has some variation, for instance a close-up portrait where there are shadows on a persons face.

I use Center Weighted metering all the time. Center is classic for portraits, but usually any subject is in the center. Center is more Old School, and less Whiz Bang, but Matrix metering will affect that center by seeing bright highlights in the corner somewhere (not a plus).

What I like about "Spot" metering is how the exposure calculation follows the focus-point (unlike most Canon cameras where this is not the case). Matrix metering does a pretty darn good job, IMO, the vast, vast majority of the time. When there is extreme dynamic range I'll fall back on Spot or, with the D750 and some of the other higher-end models you can choose "Highlight Weighted" which will do its best to correctly expose the shot without blowing out the highlights; it works, if not perfectly, surprising well too be sure.

Center Weighted is nice as long as you remember the metering does NOT follow the focus-point like it does in Spot metering. I would say your assessment is pretty much correct, I too think of Center Weighted as "hybrid" of Matrix and Spot metering modes but I don't care for it much because so much of the time my subject is NOT "dead center" in the frame unless I'm shooting portraits. It's just another tool in the box.

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Horoscope Fish said:

I too think of Center Weighted as "hybrid" of Matrix and Spot metering modes but I don't care for it much because so much of the time my subject is NOT "dead center" in the frame unless I'm shooting portraits.
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Center Weighted is not really that sharply defined. Its effect is more like a Gaussian bell curve shape (not a sharp circle). But larger, not comparable to Spot.

I never change it from default, but Center Weighted is selectable size. A DX frame is up to 16mm tall. Center Weighting default is a 8mm circle, but it can be 6, 10, or 13 mm diameter (if DX, and FX has its similar selections). That can be most of the important area, but this center dimension is "weighted" for 75% of the total importance. The rest of the frame has importance of about 25% (the bell curve shape). So it is kinda full frame, and we can only have one exposure setting, and to determine it, this is just saying that intensities in this center area are 3 times more important than edge intensities. Seems right to me.

For Matrix, Nikon only says Gee Whiz words, so we have no clue what it does, but the only identifiable action of Matrix that I see is that very bright spots at frame edge can reduce the exposure of the center. I don't see any advantage of that.

For example, TTL flash (including TTL BL) only meters in the center. It is not exactly the same area as Center Weighted, I think a little smaller than default (DX FV Lock specs say 4 mm), but camera has its own center area for flash metering. So, Matrix or Spot or Center W selection is ignored by flash metering, it always uses its own center area (Spot Metering does however switch TTL BL mode to be TTL mode, to be independent of the ambient).

WayneF said:

I never change it from default, but Center Weighted is selectable size. A DX frame is up to 16mm tall. Center Weighting default is a 8mm circle, but it can be 6, 10, or 13 mm diameter (on DX, FX has its similar selections). That can be most of the important area, but this center dimension is "weighted" for 75% of the total importance. The rest of the frame has importance of about 25% (the bell curve shape). We can only have one exposure setting, and to determine it, this is saying that intensities in this center area are 3 times more important than edge intensities.

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Which is why I said I think of it as a "hybrid"; as in it blends qualities of both "Matrix" (e.g. the calculation of differing areas of the frame) and "Spot" (e.g. giving more "weight" in the calculation to the center most portion of the frame). If you want get into the specific percentages of the the "bell curve" and so forth, that's fine but I don't really. The overview is all I need to effectively work with the different metering modes.

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Thanks all! It was really enlightening to learn when/why people are (or aren't) using center-weighted. It also explained why I'd never used it before; it's rare that the subject is centered for me (I rarely take portraits). BUT it's something to remember if start doing more portraiture.

When you use center weighted or spot metering you don't have to stick to the center of the frame. You can point the center at the spot you want to expose for, set the camera and then frame the shot however you want.

dennybeall said:

When you use center weighted or spot metering you don't have to stick to the center of the frame. You can point the center at the spot you want to expose for, set the camera and then frame the shot however you want.

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Right, plus the center is pretty large, and also is commonly typical of the subject anyway

We should NOT imagine that Matrix is smart enough to find our subject. It's just a dumb computer chip without a clue. It sees some light, with no idea what it is or what it means. Matrix is still center oriented, except it can be influenced by bright lights at frame edge. I've never found that to be an advantage.

Use a fixed tripod, so the camera cannot move. Then take some various test pictures in both Center and Matrix modes. There won't be much difference, but on those with reduced Matrix exposure, locate the bright edge effects (sky, etc) that caused it.

For general shots with subject at or around the centre, Centre weighed gives the appropriate exposure.

I use Matrix metering with flash or for landscape shots.

Only when I want the exposure perfect on an object, do I use spot.

One thing to note is that except Matrix metering, the other modes will leave areas brighter than the subject over exposed and dark areas under exposed. So if you want the bright areas properly exposed, use spot metering. The shadows can then be recovered in post if you shoot RAW.

aroy said:

Only when I want the exposure perfect on an object, do I use spot.

So if you want the bright areas properly exposed, use spot metering.

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Spot metering does Not give "perfect" exposure, even of the spot ... anything but that... Same as all any reflected meter can do, Spot metering merely makes the spot come out as middle gray intensity. So results very much depend on the spot selected, and it does require some thinking. If you Spot meter on a caucasian face, the standard rule of thumb is to add about +1 EV compensation, to prevent the face from being middle gray tone.

What Spot metering does do is to exclude surrounding influences.... the opposite of Matrix which seeks them out. My notion is that Center Weighted is usually the best overall compromise.