Exposure Compensation

[EOS_JD]

Makes me wonder if this is a camera thing, a lens thing, calibrated monitor or just out and out user preference?

One thing is for sure, it's NOT the monitor.

The image may look different on many different monitors but the histogram will look the same no matter the monitor. All the monitor does is display how it thinks the image should be shown and that is why it is important to have your monitor calibrated.

Properly calibrated monitors should show the image in the same way.

 

[Rusty105]

Just out of curiosity... how is everyone determining that their cameras are 1/3 stop off? What defines a 'perfect' exposure?

 

[EOS_JD]

Just out of curiosity... how is everyone determining that their cameras are 1/3 stop off? What defines a 'perfect' exposure?

You can judge by checking your histogram.

 

[Rusty105]

OK, for us Film shooters.... Is it good highlites, good shadow detail, skin tones... 1/3 stop is not a lot, doubt many could see a 1/3 diff with color negatives. Color slides are different, maybe if you had 3 side by side you could pick out a 1/2 stop diff. But 1 single image, could you spot 1/3 +/- EV?? I am just looking for way to judge my exposures.

 

[petey]

You can judge by checking your histogram.

Can you please elaborate?

 

[Helen B]

There are two main ways of determining ISO speed of digital cameras, according to ISO 12232: ‘saturation based’ and ‘noise based’. The saturation-based speed is calculated from the exposure that would reach the upper limit of the capacity of the sensor or circuitry (ie on the verge of being blown out), and it is generally the method that is used for the highest quality.

It is fixed so that in effect an 18% grey will give an exposure that is 12.8% of the exposure that would result in saturation, or to put it another way, a 100% diffuse-reflective surface will give an exposure that is 71% of the exposure that would result in saturation. That is half a stop of overexposure latitude over 100% reflectance and just a shade less than three stops of headroom over 18%.

This means that if the camera setup follows the ISO standard, and there are no specular highlights in the picture, a reading from an 18% grey card will give an exposure that results in no part of the image being exposed at more than about 2/3 of the maximum the sensor/circuitry can handle. (The highest diffuse reflectance of everyday objects is around 95%, and most of the things we call ‘white’ are 90% reflective or less).

This headroom could be seen as an allowance for specular highlights, or for metering off areas with less than 18% average reflectance, or a combination of those.

Therefore it should be no surprise that an exposure compensation of up to +⅔ of a stop can be given by photographers who meter carefully.

Best,
Helen

 

[Tasmaster]

Another brilliant in-depth piece of info, thanks Helen.

 

[Garbz]

I don't understand this either. I don't think the D200 has a bias in the meter. Infact I just tested that theory took a shot of a sheet of paper out of focus in matrix and centre weighted average. The histogram showed an almost single line going straight up the middle. Now if I remember correctly the camera is supposed to average the scene to middle grey right?

I'm sick of this "my camera is doing it wrong" attitude. No your artistic direction just doesn't line up with what the camera is producing. If you insist on increasing the exposure by +0.3EV then for god sakes just hard set it in the custom settings menu. That's what it's there for.

 

[christopher walrath]

Hey, petey? What's wrong with Ansel Adams? He had a lot to do with that automatic metering system you're using in a round about kinda before digital was around kind of way. He can't be all that bad.