# Canon XS Metering Modes??



## wmc1117 (Jun 19, 2009)

I am having a little trouble with my metering for my Canon XS.  1) I do not know when to use which mode, Center-Weighted Average, Partial Metering, or Evaluative Metering.  Could someone explain to me the benefits of each, or which is the best to use?  Also if someone could clarify for me when I go to take a meter read in manual and half press the shoot button the red dots register what the camera is focusing on but is that also what it is using for the meter read?  Thank you for your time and help.


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## Josh66 (Jun 19, 2009)

Center-Weighted Average
Does what it says.  Averages the entire scene, with added emphasis on the center.

Partial Metering
Like Spot metering, but the spot is bigger.  Only meters a small area (usually in the center, sometimes attached to the active focus point)

Evaluative Metering
Averages out the entire scene.  Tries to get a good exposure for everything.



wmc1117 said:


> Also if someone could clarify for me when I go to take a meter read in manual and half press the shoot button the red dots register what the camera is focusing on but is that also what it is using for the meter read?


No.  In most cases this is not what is happening.  In Partial/Spot metering, it may be metering from the active focus point - but it's usually just the center.

Evaluative & Center Weighted meter the whole scene.


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## Big Mike (Jun 19, 2009)

There really isn't a right or wrong when it come to metering modes...but it does help if you understand which mode you are in, and what that mode is doing.  It's fairly simple, partial metering uses only the center area.  Centre-weighted uses the whole scene but gives more precedence to the centre and Evaluative uses the whole area (or thereabouts).

If you are shooting a landscape with different tones throughout, you might choose evaluative.  If you are shooting a portrait of a single person with a lot of background around them, you might use partial or centre weighted so that you are metering for the person and not the background.

The metering mode does not change (or shift position) based on the active focus point (not to my knowledge anyway).  The active (red) focus point light is only to tell you which point is active.


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## Josh66 (Jun 19, 2009)

Big Mike said:


> The metering mode does not change (or shift position) based on the active focus point (not to my knowledge anyway).  The active (red) focus point light is only to tell you which point is active.



Some cameras attach spot metering to the active focus point, not sure if the XS does this though (probably not).


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## Big Mike (Jun 19, 2009)

I thought that might be the case...especially with the higher end 'Pro' bodies...but I don't know about something like the XS.


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## wmc1117 (Jun 19, 2009)

I just have been having trouble with some of my metering.  Its hard for me to decide where to take my meter reads off of for specific scenes.  Specially the ones where there is a dark foreground and bright background.


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## Big Mike (Jun 19, 2009)

This may not be what you are asking about, but it may help.

Understanding Histograms

Expose Right


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## Josh66 (Jun 19, 2009)

Well, it depends on what mode you're in - but I'll assume you're in Partial, since that's what I use the most and am most familiar with...

When you have different levels of light in the scene, you have to decide what is the most important thing to be properly exposed.  That's what you meter off of.

In evaluative or center-weighted average, it doesn't really mattter - it's looking at everything.


When Evaluative or Center-Weighted are giving you bad results - try Partial.

Partial is a lot more specific.  It only meters what you point it at.  All you have to know is what to point it at.


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## wmc1117 (Jun 19, 2009)

Ok thanks I think Partial is what I was looking to use...I have been using Center-Weighted...cause most of my shots have been having a lot of green in them so I was trying to expose with the -2/3 and I think it was picking up more than just the green.


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## wmc1117 (Jun 19, 2009)

I was confused for this shot where to take the meter read.  I knew I wanted a flowing waterfall and not the streaking one like it was.  Would you have recommended setting the shutterspeed to something like 1/4 and then taking a meter read off of the green above the waterfall?


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## Josh66 (Jun 19, 2009)

wmc1117 said:


> I was confused for this shot where to take the meter read.  I knew I wanted a flowing waterfall and not the streaking one like it was.  Would you have recommended setting the shutterspeed to something like 1/4 and then taking a meter read off of the green above the waterfall?



In this situation - with moving water, first you have to decide how much movement you want to show.  That's your shutter speed.

Next, meter it.  I would probably meter off of the trees, or maybe the rocks.
Adjust your aperture (and ISO, if you can't get what you want) untill the selected shutter speed is giving you a "good" exposure (zeroed out meter) on whatever you're metering off of.

Metering off of the (white, and pretty bright) water will tend to make everything else underexposed.

You camera is going to try to make whatever you meter off of a neutral grey (imagine that it is B&W)


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## Big Mike (Jun 19, 2009)

A more in depth way to meter a landscape scene, is to use your smallest metering area and meter different parts of the image.  This is one reason why higher end cameras have a spot metering mode, rather than just partial.  

What you would do, is meter specific areas...the rocks, the greenery etc and find out what the difference between them is.  It might be 4 stops, for example.  They you take into mind that a digital camera has a native latitude (the dynamic range) of about 5 stops (it may be a little more these days).  
So then you figure out what exposure level you should shoot at, so that it covers (as best as possible) the range of your scene.  This is sort of the idea of the evaluative metering mode, but as the camera is just a computer, it can be easily fooled.

Now, this shot is a little harder because running/bubbling water will 'always' turn white which makes it very hard to expose with a darker scene.  

There are other things you can do to 'even out the light' in a scene.  One would be to use a split or graduated filter to block off the brighter areas.  Another would be to add light (flash etc) to darker areas.  Yet another would be to take multiple shots and use software to combine them...or just edit areas of the image selectively.


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## Josh66 (Jun 19, 2009)

Big Mike said:


> A more in depth way to meter a landscape scene, is to use your smallest metering area and meter different parts of the image.  This is one reason why higher end cameras have a spot metering mode, rather than just partial.



Yes, this would be the best thing to do.

Read up on the zone system.  This will help you decide where different elements in the scene need to be on the zone scale (and how to put them there).

Your meter will try to place everything in zone V.


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## Big Mike (Jun 19, 2009)

We forgot to mention the option of a hand held meter.  Many hand held light meters can be use as 'reflective' light meters...which is essentially the same as the camera's meter...but you can also use them as incident light meters...meaning that you put the meter in the light that is hitting your subject and measure the light (rather than the light coming off of the subject).  This can help you avoid the problems of trying to figure out the tones and reflectivity of different parts of your subject/scene.  Of course, if the scene has parts that are too bight and too dark...no single setting will get it all in one shot, no matter how you meter.


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## wmc1117 (Jun 19, 2009)

Thank you, I will read more in depth into that, do you guys use a gray card at all for your meter reads?


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## Josh66 (Jun 19, 2009)

wmc1117 said:


> Thank you, I will read more in depth into that, do you guys use a gray card at all for your meter reads?



I do.  I find it very helpful not only for metering, but for white balance as well.

I don't use it every time, but if my subject is darkly (or brightly) colored, it really helps to nail the exposure the first time.



EDIT
If you're going to be shooting a lot of landscapes - green grass is good to meter off of too.  That's like the color version of a grey card (if that makes sense).


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## wmc1117 (Jun 20, 2009)

I read Understanding Exposure, and he suggested using the green in a landscape shot and set it to -2/3 exposure, just curious if thats what you guys use as well?


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## Josh66 (Jun 20, 2009)

I do, but I don't set it to -2/3 - I just go with it as is.

In bright sun, you might need to compensate a little.


Just try to meter off of a patch of grass that has the same light falling on it as the rest of the scene.

(Don't meter on a shady patch if almost the whole scene is in direct sunlight.)


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## wmc1117 (Jun 20, 2009)

ok, just curious...when is it a good time to set the exposure to -2/3?  In the book Peterson says -2/3 is a good go-to for all green dominated shots?


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## Josh66 (Jun 20, 2009)

I guess it all depends on what kind of results your meter is giving you.

Personally, I don't really use exposure compensation on anything...  Maybe I'm just lucky and my meter is always right.

If you find that you're getting underexposed shots when your meter is telling you that it should be good, set the exposure compensation to the positive side.  If you're getting overexposed shots, set it to the negative side.

It's probably because foliage is more reflective than a grey card, so it _should_ be reflecting more light back.  I've never noticed it causing any problems though.

For now, just leave it alone.  Once you get them on the computer (I don't think I would judge them by looking at the small LCD), if they look too bright try setting your exposure compensation to -2/3.


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