Lens hoods are nothing new, they have been around for as long as there have been lenses, many old-school photographers couldn’t imagine a lens without a complimenting hood. Lens hoods are an important part of any system. Circular rubber hoods are still a popular option today just as they were 60 years ago; however hoods have had to change in order to keep up with advances in lens design. The result is that many of today’s lenses use hoods that aren’t circular; in fact they look petal shaped.
The biggest issue with using a lens hood becomes evident at wide angle lens lengths and is most common on wide angle zoom lenses. On a wide zoom if we used a fully circular hood we would notice that the corners of our images would be darker than the center of the image (vignetting). This darkening is caused by the hood partially blocking the light at the corners of the image from striking the film plane.
Decades ago photographers found that by cutting out four quarter shaped notches in their hoods the vignetting problem went away. My high school photo instructor taught me this trick using rubber hoods ages ago and it generally worked. However the lens manufacturers took it a step further by actually measuring the angle of view for each lens and pairing it with a computer designed and modified lens hood. These petal shaped hoods are now common.
Some of the petal shaped hoods look downright silly – they seem to have more material in the mounting ring than in the hood’s petals – but they are still effective. In addition, where a fully circular hood could just thread on most petal shaped hood will have registration marks and a bayonet style attachment in order to get them properly aligned on the lens.
That seems like an awful lot of engineering dedicated to such a lowly piece of camera gear. In fact today more photographers skip lens hoods than ever before. Since going without a hood seems to be the trend why is it that we encourage hoods as much as we do?
Every time we hold our hand over our eyes to shield them from the sun we prove why our digital camera lenses need a lens hood. By blocking the strong glare of the sun the scene we are viewing gains contrast and color, and isn’t that exactly what we want in your photos?
A rigid plastic lens hoods also provide some protection to the front element of the camera’s lens – kind of like a bumper. A lens with a hood on it is less likely to be damaged by incidental impact.
We get a lot of questions about using lens hoods and one of the most common is if the hood should come off once we step inside to shoot. The answer is conditional. If your camera is equipped with a hotshoe flash you may not need to take the hood off for indoor shooting. However when relying on the camera’s built-in flash we suggest that the hood should always come off. The problem isn’t so much the hood as the height of the flash. If the flash is close to the lens (like a built-in flash is) the lens hood is more likely to block a portion of the flash’s light creating a half-moon of shadow in the pictures.
What kind of hood is best? This depends on the length of the lens it will be attached to. With a digital camera lens that is 28mm or shorter we recommend a hard plastic petal shaped hood. For lenses with lengths of 35mm or more the fully circular hood design in either hard plastic or folding rubber will do nicely. When I am shopping for my own lenses I look for the hard plastic hoods since they offer the added benefit of additional lens protection.
We also suggest that photographers should own one hood for each lens. Sharing hoods between lenses can get confusing in low light situations. Hoods are comparatively inexpensive and the money saved by sharing one hood between lenses is out weighed by the impact hoods have on the resulting images.
Conclusion: Lens hoods are a necessary part of any camera / lens combination. By reducing strong, stray light a hood intensifies both color and contrast. Hard plastic lens hoods provide some additional lens protection from bumps. Lens hoods are an inexpensive accessory that can improve any photographer’s outdoor images.