Friday, January 22, 2010

Bright Objects in the Picture

Makin' some cocoa...

I was taking pictures at church the other day for an illustrated kitchen procedure manual. The camera, as usual, set the exposure automatically. And every one of the images was too dark.

Remember that your camera, when on automatic, will want to make the brightness of the entire photo end up at a nice average gray. So if there's a big white object in the frame, the camera will want to make the picture darker. If there's a big black object, it will want to make the picture lighter. Until everything comes out "average." Which is normally OK.

But if the brightness comes from something other than your subject, like white snow or bright sand, then the camera is being fooled into lowering the exposure, and therefore making your REAL subject too dark.

The general rule is to overexpose images of sand and snow by about a stop. But it's not just white granular stuff. This rule applies to any bright scene such as a kitchen with white walls, floors, shiny steel appliances, etc. Shiny appliances too? Yep, particularly when you're using a flash which just treats these objects as reflectors.

Even the shot above was a problem - white cup, light hands, white walls, etc. The big piece of black did help, but I still had to brighten this a little.

The common mistake, and mine as well, was the failure to remember that when you're using automatic exposure with bright objects in the frame, the system will misread that brightness and make the image darker in order to compensate - to that average gray.

In order to "uncompensate" I had to lighten each picture I took using software when I discovered my mistake later. Avoid having to do this in post-process.

Tip: look at your backgrounds - are they light? Are they dark? Are there any other items in the frame that are much different, in terms of lightness than your subject. If so, it's time to compensate and watch your histograms.


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