Why and When to Use Camera Lens Hoods

Purpose, Advantages, Problems and What They Do

Nov 12, 2008 Yuen Kit Mun

New SLR camera lenses often come with a removable hood. Though cumbersome, lens hoods can improve picture quality, and even protect the lens from damage.

Lens hoods can be made from metal, plastic or rubber. They can be round, square or petal-shaped. They can be screwed on to the lens filter ring, mounted on the lens barrel or permanently fixed on to the lens as a sliding sleeve.

Lens Flare

The main purpose of a hood is to prevent stray light from entering the lens through the side of the lens. Light from just outside the photo border can still enter the lens, bouncing inside the barrel and reflecting off the lens surfaces to reach the image sensor indirectly.

This light can reduce the contrast and color saturation of the photo. This is why movie cameras are always used with a hood (matte box), as can be seen in any "The Making of ..." movie documentary. With the vast sums of money spent on making a movie, only the best image quality will do.

Digital SLR photographers can similarly improve their images. Modern lens coatings make the improvement less noticeable, but still significant especially when pointing the lens close to the sun and other strong sources of light.

DSLR Built-in Flash and Lens Hood Issues

With today's large zoom lenses, it is possible for a lens hood to block the camera's internal flash. This will cause a shadow to appear at the bottom of the photo.

Workarounds:

Using an external flash
Using only the tele end of the zoom
Removing the lens hood

Lens Mechanical Protection: Drop-proofing Lenses

Though not their main purpose, lens hoods can protect the lens from damage. Accidentally dropping a camera on to the ground may result in no more than a broken hood, if the camera happens to fall on its hood.

This is especially true if the lens is designed so that the hood is fixed to the lens barrel, and not the more delicate moving front lens element.

Hoods also help keep fingers, and fingerprints, away from the lens. Using a hood means having to clean the lens less often.

Petal Hoods and Vignetting

Hoods for wide angle lenses (including standard and kit lens zooms) are petal-shaped to efficiently match the rectangular photo image (petal hoods are not needed for telephoto lenses because their field of view is so narrow that a long round hood can be used without blocking the lens). Turning the hood out of position can cause the hood to block the corners of the photograph (vignetting).

Photographers should regularly check that petal hoods are in position. Sticky tape can be used to stop the hood from turning.

The Best Lens Hood

Each lens should have its own customized hood, provided by the manufacturer. There is no one best hood for all lenses. The optimal hood size and shape depends on the focal length of the lens.

If the original lens hood is not available, a generic third party lens hood can be used. These will be circular rubber hoods, screwing on to the lens filter ring. To avoid having the hood block the corners of the photo, the rubber hood can be cut to fit.

Lens Hood Storage

Depending on how the lens is stored, the hood may have to be removed in order for it to fit into its container. For convenience, the len's original box can be replaced with a larger container so that the lens can be stored with the hood attached.

Why Use Camera Lens Hoods?

Hoods are not without problems, having issues with built-in flashes and vignetting. However, photographers willing to work with their limitations can expect clearer (higher contrast) images under some circumstances.

The additional mechanical protection a hood can provide will make them especially attractive to owners of expensive lenses.

Novice photographers should give hoods a try before deciding to leave behind these bulky, inconvenient, deceptively simple-looking pieces of plastic or metal.

Resources

The copyright of the article Why and When to Use Camera Lens Hoods in Photography is owned by Yuen Kit Mun. Permission to republish Why and When to Use Camera Lens Hoods in print or online must be granted by the author in writing.

Petal-shaped Lens Hood on a Typical Zoom Lens

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