Understanding Nikon D5100 Exposure Meter

[TheFlyingScotsman]

I'm posting this here because it's the only forum that seems relevant to "light" and I didn't want to just post it in the chit-chat section. Sorry if it's in the wrong place.

I have a Nikon D5100. I'm getting my mind around Bryan Peterson's Understanding Exposure, and the Photographic (or Exposure) Triangle. I understand how shutter speed, aperture, and ISO relate to one another. I've shot a few hundred photos with the camera to get an understanding of how changing the numbers effects the exposure.

But I'm also trying to understand the exposure indicator on my camera. I understand that when I shoot in auto mode, it serves as an "exposure indicator." When I shoot in manual mode, it serves as a light meter - and these are two different things.

What I'm not understanding is this: should the indicator/meter be set as close to the middle as possible (e.g. balanced) to get a clear, balanced picture? Because that's not happing with me. If I set my ISO at 200, then adjust my f-stop and shutter speed so that the indicator is in the middle, I get an underexposed picture almost every single time. If nudge up the ISO or adjust my stops/shutter speed, I can fix the exposure easily enough and it ends up looking fine.

But I feel like I'm ignoring the meter, as if it serves no purpose. Am I doing something wrong? Is this a camera issue?

My lens is AF-S Nikkor 18-55 mm 1:3.5-5.6.

[RichardTaylor]

For available light:

For an "average" (greyish) scene it should be ok with the needle in the middle.

If you are shooting a bright scene,. such as snow or beach then the meter will be fooled, as it is expecting an average scene, and think there is too much light so underexposed images will result.

The converse applies to dark scenes.

Do you have any exposure compensation dialed in?

What metering mode are you using?

[TheFlyingScotsman]

Originally Posted by RichardTaylor

For available light:

For an "average" (greyish) scene it should be ok with the needle in the middle.

If you are shooting a bright scene,. such as snow or beach then the meter will be fooled, as it is expecting an average scene, and think there is too much light so underexposed images will result.

The converse applies to dark scenes.

Hmmm . . . maybe I just need more experience evaluating light? What qualifies as a bright or dark scene? You're examples are good: would the living room of my house (it's a 1924 Craftsman bungalow with 2.5 sides of wall windows) be "dark"? (I know you can't give a "positive" answer, but in general the natural light "seems" bright and the room is open).

Originally Posted by RichardTaylor

Do you have any exposure compensation dialed in?

Exposure compensation is set to -5.0 (but I didn't set it - does the camera automatically adjust this?). Flash compensation is set to 0.0. Should I be using it (exposure compensation, that is)?

Originally Posted by RichardTaylor

What metering mode are you using?

Metering mode is "matrix metering"? Not sue what it means . . .

Thanks for the help.

[RichardTaylor]

(1) Here is an example of a dark scene or subject. Overcast day
All that black engine is fooling the meter.

Notice the exposure compensation.



Camera Canon EOS 5D
Exposure 0.005 sec (1/200)
Aperture f/6.3
Focal Length 35 mm
ISO Speed 800
Exposure Bias -1 EV

An average scene would be a landscape, rolling hills, a few trees & blue skies. with the sun behind your back.
Your living room may be ok a "standard scene"

(2) The exposure compensation should normally be at zero. Change it and it may solve your problem.

You use exposure compensation when shooting in P mode, Shutter priority, Aperture priority if needed. In Auto it should have no effect. In manual mode it only affects the display - not the exposure.
See page 70.

You use it when the subject dictates.

(3) Matrix metering means the camera looks at the whole scene to determine the exposure needed.
Centre weighted means it mostly takes what is in the centre are of the screen to determine the exposure.
Spot metering means it just looks at a spot, usually defined in the viewfinder, in to determine the exposure setting. You have to be very carefukl where you point it.

See page 68. of the english user manual.

I use mostly Matrix metering (Canon give it a different name) and dial in exposure compensation when needed (how much comes form experience) and checking the histogram.

----------------------

In this example I was using matrix metering with some exposure compensation dialed in.
If I was using centre weighted, with no exposure compensation, the pic would have came out over exposed as the metering system would mostly see black think it need more light.
Spot metering, with no exposure compensation, the dress would have under exposed the pic as the metering system would have thought there was too much light. Spot metering off the skin probably would have been ok.

.

Camera Canon EOS 40D
Exposure 0.003 sec (1/400)
Aperture f/2.0
Focal Length 135 mm
ISO Speed 3200
Exposure Bias -1 EV
Aperture priority.




.

[Doug Sundseth]

Originally Posted by TheFlyingScotsman

Exposure compensation is set to -5.0 (but I didn't set it - does the camera automatically adjust this?). Flash compensation is set to 0.0. Should I be using it (exposure compensation, that is)?

That's your problem. When you use EC with manual, you're telling the meter that you want the meter centered when the camera is actually seeing the scene as under- or overexposed.

For your situation, the meter will be centered when the camera thinks the scene is 5 stops underexposed. Reset the EC to 0 and you should get a better result when you center your meter.

[TheFlyingScotsman]

Thanks to both of you for your help. Yes, setting the EV to 0.0 did the trick.

@ RichardTaylor: Thanks for the information. That was very helpful and I understand light a little better.

But what was really helpful was you clueing me in to the fact that there was another manual for my camera. The one I've been using (styled "User's Manual") has only 82 pages and none of the information you referenced. For a minute, I thought I was crazy. Then I checked the camera box again and, sure enough, there was a CD that got stuck in with the warranties with the "Reference Manual" on it.

Thanks - this will be very helpful in the future.

[RichardTaylor]

Glad to hear.