Spot metering and D2...

[krabat]

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Not bad, daveleo... Black is almost black, and white is almost white... To be honest, I did not expect such a clear difference.

 

Well, if you are shooting in snow, an over-exposure by +1 or sometimes even +2 is also recommended.

[jack650]

I agree with Thorsten.

 

There should have been a reference image taken of an 18% gray at your reference aperture - f3.2 - to measure light at the time of the experiment. This reference gray image will be used to compare it against the gray backgrounds in your three metering modes.

 

Since every camera's metering system is calibrated to 18% gray, the photographer is expected to shoot at an 18% gray scene. The camera will then deliver a perfectly exposed image of that 18% gray scene provided you shoot at the shutter speed determined by the metering system. If the scene is not 18% gray, exposure compensation is resorted to, but this is a separate subjective decision by the photographer.

 

My interpretation of the spot meter test is this: by pointing the spot meter square to the black square, you have told the camera that that spot is 18% gray. The metering system then kept exposing for a full minute until that black patch became 18% gray. If there had been a black patch near the perimeter of the image, you would probably see this black patch completely washed out into 18% gray by overexposure.

 

Your black-patch-over-white experiment will probably yield accurate expected results for spot metering. It is hard to draw any conclusions for the other two modes because we don't know the location of the sampling points of the metering system. However, you can compare the degrees of gray in the white backgrounds using 1) your reference image and reference shutter speed and 2) the gray in the spot meter test.

 

Just my $0.02.

 

Regards,

Frank

[jack650]

"The metering system then kept exposing for a full minute until that black patch became 18% gray."

 

Sorry, this should have read "full second".

 

 

Frank

[daveleo]

Frank

 

i also agree with Thorsten, but i am not sure that we were all answering the same question(s) on this topic.

 

what bothered me was that my D2, in the auto modes, was making white areas gray and making black areas gray due to it's weighted averaging scheme.

my objective was simply to convince myself that my D2 could properly record black-to-white and how i could control that.

 

the strict process of the "experiment" was really secondary to my wondering what was going on.

 

in the olden days i never left home without my incident light meter .... where did i go wrong ?

[Overgaard]

Frank

 

in the olden days i never left home without my incident light meter .... where did i go wrong ?

 

You read an ad somewhere that said the camera technology has evolved to a level where it will for sure take great photos.

 

The same ads promoting that you can just shoot raw and decide exposure and white balance later

 

In any case, the middle exposure of your first experiement actually show exactly 18% (more or less) middlegray in the white. So the meter definitely got the two tones in the picture, and hen decided to make most of the image 18% middlegrey. Not bad at all, considering how extreme the scene was.

[mobeyone]

 

my apologies if it seems that i "hijacked" this thread ... but it was a very provocatve question that threw me a curve ball.

 

Glad you did to be honest, lots to read and digest which is why I posted the question in the first place.