Wednesday, December 1, 2010

Making Blue Skies Blue! [Underexposing a bit.]


Ok. So what's the secret to making the sky in your photos more dramatic, more impactful? There are many tips-and-tricks, but today I'm just going to cover one of the easiest -- slightly underexposing the picture.

Background
When I think of a photograph with a dramatic sky, I think of a sky with lots of nicely saturated colours. Not a sky that is pale white. If you look through your photos and notice that the sky doesn't seem as dramatic as when you were there taking it, then read on.

The reason that skies end up looking pale (white) in photographs is usually because the sun (and the sun light reflected in the sky) is just so powerful that it ends up overpowering the sensor in your camera. Instead of the blue sky that you see when taking the picture getting recorded, the camera's sensor gets maxed out. All the Red, Green and Blue sensors all reach maximum. And the combination of maximum Red, Green and Blue is . . . white! The sky is over exposed.

What needs to happen is that the sky needs to be exposed slightly less in order to bring its light within the range of your sensor.

When you underexpose the picture, what happens is that not as much of the sunlight gets captured, and so the sensor on your camera doesn't get maxed out. Some of the pixels will become white, but a lot of them will become various shades of the sky that you see. Instead of a wall of white, you'll get an interesting and dynamic sky.

How to underexpose a picture when taking it.
Ok, some cameras have a "Sunrise or Sunset" scene mode. When you select this mode on your camera, it will automatically underexpose the picture a bit.

Now, if your camera doesn't have this scene mode or if you're not happy with the result, you have another option.

If you're using a point-and-shoot camera or a dSLR in one of its auto modes, you can use "exposure compensation" (if your camera has this feature) to force the camera to underexpose the picture slightly. Read your camera manual (yes they are actually useful for something) and change the "exposure compensation" to "-1.0" and take a picture. If the picture seems a little too dark, change it to "-0.7 or -0.3". If the picture seems a little too light still, change it to "-1.3 or -1.7". In essence, the "exposure compensation" feature on your camera lets you tell the camera to under (or over) expose the picture, giving you creative control to get the photo you want.

This also works if you use flash. If you do turn down your "exposure compensation" when using flash, you may want to experiment turning up the "flash compensation" on your camera slightly as well. So, although you are underexposing the picture, you are turning up the flash so that your close subject matter gets properly lit. I often hear this described as "minus-one, plus-one" (ie. -1 exposure compensation, +1 flash compensation).

If you are using a dSLR camera in its manual mode and are controlling both the aperture and shutter setting, then simply change one or the other in order to underexpose the picture. For instance, if you are shooting at a shutter speed of 1/500 sec, then use 1/1000 sec instead.

Hope this helps!
Take care,
Glen -- DigicamJunkie.com

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