A very common problem novice photographers face is an overly bright sky. It can cause dull images with a washed out or completely white sky, glare, low contrast and even under-exposed subjects.
The first thing to know about this issue is that it is completely normal because, in the day time, the sky is usually the brightest part of the scene and all cameras have a limited dynamic-range. The dynamic-range of a camera is simply the amount of contrast it can capture in a single image. As a matter of fact, this dynamic-range is the reason why the concept of exposure exists!
Now, if you darken the exposure by applying negative Exposure-Compensation, the sky will get darker and more blue. This will cause other elements in the image to darken and some may become under-exposed.This happens because a change in exposure is global.
What needs to be changed is the relative brightness of the sky compared to the foreground using one of these techniques:
- Come back later or earlier during the golden hour. That is the period of time when the sun is within 6 degrees of the horizon, close to sunset or sunrise. This is the ideal solution in terms of exposure.
- Use a circular polarizer. This darkens the sky to varying degree depending on the angle of the sun relative to where you point the camera and the amount of moisture particles in the air. For relatively bright subjects, this often works but it has a limited effect.
- Darken the exposure, use flash to brighten the foreground. This only works for foreground subjects which are sufficiently close and small to be lit be the flash.
- Use Exposure-Fusion or HDR followed by tone-mapping. These are techniques to obtain an image from multiple exposures. You really need a static scene with no moving subjects for this to be easy. Some recent cameras have HDR built-in now and will take between 2 and 4 shots and create a composite directly in the camera.
- Use a Graduated Neutral Density filter (GND). This works by darkening a portion of the image as long as the division between sky and foreground forms a straight line. Otherwise it looks unnatural. Great for shooting shoreline and beaches though. Digitally this can be simulated by multiple shots which are merged together in Photoshop or another image processing software.