Why does it matter what the metering is set at?

[alfa147x]

So i normally set my 30D in manual thus i set the shutter iso and aperture
so why does it matter then what the metering is set to?

this is what i understand correct me if im wrong
When one changes the metering to... say spot metering it uses a small spot to determine the aperture shutter speed and iso ... right?

thanks

 

[OdiN]

It affects how your cameras meter reads the scene.

Spot metering is usually the circle area you see in your veiwfinder - it will meter off of that. Useful if you have a backlit subject and don't care as much about the lighting blowing out or things like that.

You don't want to meter the whole scene if it has a lot of extremes but what you're most interested in isn't taking up most of the shot.

Or say you're metering a wedding shot - the bride is wearing a bright white wedding dress - spot metering on the dress can ensure that you don't blow out the highlights on the dress - which is one of the most important things for wedding photography. Evaluative metering would take more of the scene into account.


Try this. Setup a scene and use a white piece of paper in the center of the shot which is lit well, and just kinda whatever else. Keep the camera pointed at the white paper. Go through your different metering modes, and see what the camera tells you is the "correct" exposure in each - and take a picture. You should see a difference in shutter speed, etc. that you end up using for each one - and look at the exposure difference between them.

 

[kalster]

in fully manual mode (M) it doesn't matter, since you are setting the exposure yourself (iso.shutter speed , aperture), spot/matrix/evaluative only come into play in auto exposure modes(A, P) or other modes (Tv, Av, Tav)

 

[OdiN]

Originally posted by: kalster
in fully manual mode (M) it doesn't matter, since you are setting the exposure yourself (iso.shutter speed , aperture), spot/matrix/evaluative only come into play in auto exposure modes(A, P) or other modes (Tv, Av, Tav)

This is not true.

While in the auto exposure modes, yes it will use those to determine the "proper" exposure. In manual mode you can set it to over that amount. Even in auto modes you can dial in exposure compensation if you want I believe.

But that doesn't mean that the exposure modes only come into play in auto exposure modes.

They also come into play in manual - if you are shooting evaluative metering mode - it will put your meter "centered" on 0 at different settings than if you were using spot metering mode.

So say you were shooting evaluative - a scene with a bride in a wedding dress perhaps. Let's say this is your meter, while pointed at the bride:

-2___-1___0___+1___+2


Now switch to spot metering mode, and you might get this with the same shutter/aperture/ISO:


-2___-1___0___+1___+2


What this is telling you is that in evaluative mode - the whole scene is taken into account and the camera is saying that it's exposed properly (centered). While when you switch to spot - the camera is using primarily the white dress and telling you that with these same settings, you're overexposing. If you took the shot in evaluative, you would ruin the highlights in the dress - not what you want. But with spot, you can meter for a more precise area and get better results. However, you can (in manual mode, or with EC) adjust. So even while using evaluative, if there is a white dress in the shot and you know that you need to "underexpose" by what your camera is telling you, you can do that.

 

[kalster]

That is true, I guess in manual mode even though you set the exposure the camera takes a reading which you can use as a guide , and that differs based on the metering mode, where as in auto exposure mode it sets the exposure.

Good info, thanks

 

[OdiN]

Originally posted by: kalster
That is true, I guess in manual mode even though you set the exposure the camera takes a reading which you can use as a guide , and that differs based on the metering mode, where as in auto exposure mode it sets the exposure.

Good info, thanks

Precisely

And this is, of course, why your camera has a meter. Imagine shooting in manual mode, but not havnig a meter at all. You could guess and chimp after the fact, but not very useful, right?

 

[soydios]

Odin, you're confusing everybody.

In manual mode, you set all the parameters (ISO, shutter speed, and aperture), but the meter is still active, telling you what it thinks of your choices. changing the meter program changes how it meters the scene, and what it tells you about it.

general example:
you want to nail the exposure on a gray card in a scene. you set the camera to spot metering, and adjust your parameters until the meter agrees that the gray card will be properly exposed.

personal example:
I do a lot of stage photography. when I do, I set the meter on my D50 to center-weighted average, because spot metering is too fickle for quick use and matrix metering is distracted by large black areas on stage. this way, while taking photos in manual mode, when the lights change, I can put the metering circle over a representative area, and adjust my exposure to compensate. in this way, I can adjust my exposure quickly, without having to test shots, which I might not have time for if a crucial shot comes up in two seconds.

 

[OdiN]

How am I confusing everyone, that's exactly how it works!

 

[ElFenix]

Originally posted by: OdiN

Originally posted by: kalster
That is true, I guess in manual mode even though you set the exposure the camera takes a reading which you can use as a guide , and that differs based on the metering mode, where as in auto exposure mode it sets the exposure.

Good info, thanks

Precisely

And this is, of course, why your camera has a meter. Imagine shooting in manual mode, but not havnig a meter at all. You could guess and chimp after the fact, but not very useful, right?

shooting with a broken meter isn't that hard. sunny f/16. as long as the light is consistent you just set the shutter, set the aperture, and have fun

 

[OdiN]

Originally posted by: ElFenix

Originally posted by: OdiN

Originally posted by: kalster
That is true, I guess in manual mode even though you set the exposure the camera takes a reading which you can use as a guide , and that differs based on the metering mode, where as in auto exposure mode it sets the exposure.

Good info, thanks

Precisely

And this is, of course, why your camera has a meter. Imagine shooting in manual mode, but not havnig a meter at all. You could guess and chimp after the fact, but not very useful, right?

shooting with a broken meter isn't that hard. sunny f/16. as long as the light is consistent you just set the shutter, set the aperture, and have fun

I'm not talking about nicely lit outdoors scenes - I'm talking about indoors or difficult lighting during something like a wedding - you don't have time to "guess" for that candid that happens only once

With landscape stuff - you can get really good at nailing exposure without a meter - check out the zone system. You use it long enough and you don't really rely on the meter anymore.

 

[alfa147x]

Ok so when im in manual and i look down a see this
-2___-1___0___+1___+2
|
its just telling me how far off i am from what is recommends

 

[kalster]

yeh, that means you are under exposing, at least that is what the meter thinks

 

[alfa147x]

how correct is the meter?

 

[Zenmervolt]

Originally posted by: alfa147x
how correct is the meter?

Depends on the scene, the metering mode, and what you want the scene to look like. Seriously though, the meter is typically very accurate as long as you take into account how it is metering the scene.

ZV

 

[ElFenix]

Originally posted by: alfa147x
how correct is the meter?

are you pointing it at something black and non reflective?

 

[alfa147x]

Originally posted by: ElFenix

Originally posted by: alfa147x
how correct is the meter?

are you pointing it at something black and non reflective?

well just before dinner i was playing around with it by taking pictures of my fireplace (lights were off, little light was coming from the kitchen) and the meter worked perfectly

i think i shot at 3.5 and a shutter speed 1.5 seconds at ISO 200