Managing light across a wide angle

A common hurdle with wide angle lenses is strong variation in the intensity of light across an image. Using an ordinary exposure, uneven light can make some parts of the image over-exposed, while also leaving other parts underexposed -- even though our eye would have adjusted to this changing brightness as we looked in different directions. One therefore needs to take extra care when determining the desired exposure. For example, in landscape photography the foreground foliage is often much less intensely lit than the sky or a distant mountain. This often results in an over-exposed sky and/or an under-exposed foreground. Most photographers therefore use what is called a graduated neutral density (GND) filter to overcome this uneven lighting. In the example above, the GND filter partially obstructed some of the light from the bright sky, while also gradually letting in more and more light for positions progressively lower in the photo. At the bottom of the photo, the GND filter let in the full amount of light. Move your mouse over the image above to see what it would have looked like without a GND filter. Also take a look at the tutorials on camera lens filter and high dynamic range(HDR) for additional examples. A wide angle lens is also much more susceptible to lens flare, in part because the sun is much more likely to enter into the composition. It can also be difficult to effectively shield the sides of the lens from stray light using a lens hood, since this hood cannot also block any of the image-forming light across the wide angle of coverage.