Camera under default settings is severely underexposing pictures

<p>I bought a D200 recently and it's been working fine, but tonight I was taking some test pictures and they are severely underexposed compared to normal. I took the below pictures as an example, do you know what may be causing this?</p>

<p>Attaching a picture to show the problem.</p>

<p>Attaching a reference picture from my point and shoot.</p><div></div>

<p>Is that a white wall? Despite all the fancy talk about clever exposure systems in modern cameras, I don't think they can recognize each and every situation automatically. You still need to know what you're doing and adjust exposure when needed. In this case, overexpose. Check the histogram when reviewing your pictures. (If you shoot raw, you may be able to save some underexposed pictures in post-processing.)</p>

<p>Also, what metering did you use? Matrix, centre-weighted or spot? Using program + matrix, the D200 may have some tricks up its sleeve. Using spot or centre-weighted I would expect a more straight-forward metering. That is: calibrated for roughly 18% grey, and thus underexposing a subject like a white wall.</p>

<p>Incidentally, my D200 seems to do a similar job on white walls.</p>

<p>See attachment: matrix, program, ISO 1600. No correction and +2 correction. </p><div></div>

<p>And the associated histograms (in Photoshop, but they seem to match the camera close enough).</p><div></div>

<p >Using a uniform wall or placard as a target to check exposure increases the degree of difficultly 100 fold. In other words your approach is wrong.</p>

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<p >A little history lesson: In the pre-historic days of the camera and film, all film boxes included a data sheet complete with printed tables. Bright sunlight = f/16 @ 1/100 second or Overcast use f/8 @ 1/100 second Sports arena lighted f/4 @ 1/100 sec. The tables were helpful but ….</p>

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<p >A breakthrough occurred in the late 1930’s, when electric hand-held light meters came on the market. Messrs. Jones and Condit at Kodak Labs measured and demonstrate the average scene had a reflectance that statistically averaged between 18% – 20%. They suggested, using the yellow box top as an exposure determination tool (sheet film had big boxes). A box top was temporally placed in the scene, making sure it was illuminated just like the subject, and an electric reflection light meter was used to take a reading and the camera set accordingly. It worked!</p>

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<p > In 1941, Ansel Adams, a prominent landscape photographer and his friend, Fred Archer, a photo magazine editor, jointly published the Zone System which provided photographers with a method to precisely fine-tune exposure. Their zone system revolves around the use of an 18% placard (battleship gray). This card replaced the Kodak box top. The 18% gray target became the de facto standard. Today film and paper speed as well as the digital chip are calibrated and the ISO is established using the 18% gray card.</p>

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<p >Now the chip logic in a camera has severe limitations. It will always attempt to render a uniform subject the same intensity as an 18% gray target. Try your experiment again using a more diverse subject like a colorful toys etc. </p>

<p>In the first pic I did reset the WB based on a white sheet of paper and it turned out fine. I've taken multiple shots of my room and for some reason that night all my pictures under the same shooting conditions were underexposed. However it seemed to be a one night problem so I'm not too worried about it until it pops up again.<br>

Thanks for all the help though!</p>

<p >Nevertheless, images of a white wall or a dark wall or a gray wall will all be rendered 18% (battleship gray) for the reasons I related. Images of colored uniform walls or placards will be reproducing as a middle shade of their hue. This is due to the chip logic attempting to set the exposure for a middle gray of 18% reflectivity. </p>