Shading your lens
Do you know where your lens shades are? In the bottom of your camera pack perhaps? Or stuffed in the back of a closet? Lens shades are perhaps the most under rated and under used photo accessory you own. They can protect your lenses and any filters on the lens from accidentally bumping into things. They can help keep rain off of the front element of your lens. And they can shade the lens from direct light sources to help eliminate lens flare.
Lens flare is one of the more common causes of image degradation, and it’s one of the easiest to solve. Lens flare is caused by a direct source of light, like the sun, hitting the front of the lens and bouncing around inside the lens off of the many glass elements. Lens flare usually looks like a string of colored spots marching across your picture. You can see this right in the viewfinder, especially if you use your depth of field preview button. Often, just using a lens hood on the lens eliminates the possibility of lens flare.
But there is another, less obvious way lens flare can ruin an image. And it can happen when you least expect it: on a cloudy day.
Any bright source of light can cause lens flare. And on an overcast day, those clouds overhead can be that source of light. You won’t see the string of colored spots on your image like you will with the sun acting as the direct source of light. Instead, what happens is that the lens flare is big, so big that it covers the entire image, reducing the contrast and making your picture look soft.
With normal to telephoto lenses, simply using a lens hood often solves this problem. But with wide angle lenses, the lens hood may not be enough. Sometimes you’ll need the additional shading of your hand or maybe your photo buddy. One way to tell if you need to shade your lens is to simply look through the viewfinder and then shade the lens with your hand. Notice a difference? If you do, then you’ll need to shade the lens for the actual shot.
Often I’ll view a scene and simply shade my eyes as if I was wearing a ball cap. If the scene looks better by shading my naked eyes, I figure it’ll look better to the camera as well.