Camera's Metering System's Peculiarity

cjdesu6

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I took some test shots with lighting in the background so the subject is relatively dark. This picture is set to Matrix metering. I do not mind the background being blown out, but I focused on the subject and it is underexposing the subject. So I even tried Spot metering and the same happened picture. Since I am focusing on the subject (even with SPOT) shouldn't the camera properly expose the subject even if it means blowing out the background in the picture.
 

480sparky

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Focus has ZIP to do with exposure. The two are totally different animals.

It could be the spot of the camera's meter isn't small enough to meter just the leaf and ignore the bright background.
 

tirediron

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Since you say "matrix metering" I'll assume you're using a Nikon, in which case focusing can have something to do with spot metering, in that some bodies will assign the spot metering point to the selected focus point, IF you are using a single focusing point. Looking at the scene, I would expect that the plant leaves are large enough that the camera should spot meter them accurately. If you can tell us what camera and whether you were using single-point AF or not, then we should be able to diagnose conclusively.
 

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Hmm something is off here, are you sure you changed the metering mode to spot rather than just changing to a single focusing point?
 
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cjdesu6

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Since you say "matrix metering" I'll assume you're using a Nikon, in which case focusing can have something to do with spot metering, in that some bodies will assign the spot metering point to the selected focus point, IF you are using a single focusing point. Looking at the scene, I would expect that the plant leaves are large enough that the camera should spot meter them accurately. If you can tell us what camera and whether you were using single-point AF or not, then we should be able to diagnose conclusively.

Thank you everyone for your responses.

The picture was shot with a Nikon D3200 (55-200 lens) the focusing was set on Single-Point and set on both the upper-most spot and the center spot. Both came out underexposed. I shot both with Matrix and Spot metering.
 
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cjdesu6

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Hmm something is off here, are you sure you changed the metering mode to spot rather than just changing to a single focusing point?

Yes I set the metering to spot and matrix to test and the focusing was set to single point. Just don't know why the camera keeps underexposing the subject. :meh:
 

480sparky

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Yes I set the metering to spot and matrix to test and the focusing was set to single point. Just don't know why the camera keeps underexposing the subject. :meh:

Focus points do not affect exposure.

It could be that even the area that spot metering sees is much larger than the subject. So it still sees the brighter background and adjusts accordingly.
 

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I think the exposure in the first Matrix metered shot looks pretty doggone good. It's a wide dynamic range, but the camera has rendered the whites a beautiful white, and the look of the light appears very nice.

According to Thom Hogan's various Nikon camera reviews, the selected focus point used on some bodies DOES, in fact, affect the exposure the camera gives.
 
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cjdesu6

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I have tested it by illuminating half of a subject with light. I set the camera to single point focus and looked at the camera's settings while aiming at the illuminated site, I then moved it a few mm to the dark area and indeed the settings did change (the shutter speed to be exact I was in Aperture priority.) I am assuming that if the focus point did not matter the exposure would have been the same since it is metering in matrix mode.
 
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cjdesu6

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So back to the question though I changed the exposure comp to a higher value and that solved the issue of the subject being underexposed, but how are you supposed to know what to set the exposure comp at, is it experience.
 

tirediron

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My guess ('though I don't know for sure) is that on the entry-level bodies, the spot metering is the traditional few degree spot in the centre of the screen, regardless of which focusing point is selected. Why not simply read the manual? It should tell you exactly how to meter using all three metering modes. Nikon's manuals are actually very good and very clearly written.
 

Alimac1

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Have you tried getting your exposure set and using the exposure lock to hold it while you reframe?
 

480sparky

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So back to the question though I changed the exposure comp to a higher value and that solved the issue of the subject being underexposed, but how are you supposed to know what to set the exposure comp at, is it experience.

One trick is to learn how to read historgrams.

Take the shot, then zoom in on the monitor to what you want to have correctly exposed. Check the histogram of the zoomed-in image. That will tell you if the subject is exposed correctly.

At least this works with Nikons..... YMMV with other makes.
 

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A good high quality camera with some prior experience in photography can make a great difference.
 

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