Many people wonder if a lens hood is really necessary when taking photographs. While it may not always be necessary to use, it’s a good piece of camera equipment to have. Since the objective of the hood is to block out light.
Most hoods on prime lenses, those lenses that are non-zooming and have a fixed focal length, basically look like a tube with one end usually being larger than the other. Hoods for zoom lenses come with a curved opening at one of the ends. This will allow for a wider field of view at smaller focal lengths and will try to block the majority of light when the focal length is longer.
The lens hood helps block out the light that comes into the lens and creates flare when it reaches the outer elements of the lens at the wrong angle.
This light isn’t needed to take the photo and doesn’t need to reach the camera’s sensor. The light can actually create spots what are shaped like the aperture of the lens.
Lens flare can also be the result of light entering the lens directly, but this is hard to block out. The hood will at least block out light and flare that comes in from an angle.
On lenses with fixed focal lengths, the lens hood is basically solid and is coated on the inside, which blocks out as much light as possible. The felt coating will help cut down on the reflected light that comes from the plastic hood.
However, lens hoods for zoom lenses will let the light in sooner than fixed lens hoods due to the curve at the end of the hood.
Basically, a lens hood won’t cut down on the glare when the light source or the sun is actually in the image. But it can reduce the light that’s created by reflecting off of nearby objects such as white walls, windows, and water, etc. This means the hood should be used whenever you have any unwanted light reflecting into your image.
However, it’s not the end of the world if you don’t have a lens hood or have forgotten to pack it. If you don’t have a hood with you, it’s possible to block out the light by simply using your hand or a magazine or any other type of object to shade the lens from the main source of light.
But if you do this, make sure you don’t get the object in your image. This method won’t really be able to block out the reflected light, but it will be able to keep the glare out of the photo from the main source of light.
In addition, many photographers will keep the lens hood attached to their digital cameras as a way toprotect their lenses from bumps, accidental scratches, water, sand, and fingerprints etc. This is because it’s a lot less expensive to replace a lens hood than it is a lens.