Lens Hood: Why, When, How

[amberlynn]

NEWBIE question, here!

My new lens came with a hood. Cool, I guess. Except I don't understand their purpose... so far, it just feels like an in-the-way blob.

What better place than here to ask why? What are they for?
When should I use it? When shouldn't I use it?

Finally, my hood has to alignment dots, and two sides curve out longer than the other two. Which way is it supposed to go on.

I feel so dumb asking this...

[dcclark]

Purpose: lens hoods are intended to do two things. Primarily, they block light coming in at extreme angles, which can cause flaring or ghosting in your images, as the light bounces around in odd ways in lens. Second, hoods also help protect the front of your lens if you drop it or hit it with something.

That said... I never use my hoods. I find that they always feel like they're in the way. The flare/ghosting prevention works a little, but holding a hand out to one side to block the sun often works better.

Some people store them by putting them on the lens backwards, so that it comes back over the front of the lens, and then flip it when they need it. My lenses are mostly arranged so that this would interfere with the zoom or focus rings.

So -- us 'em if you're having flaring problems. Don't worry otherwise.

Edit: your hood should only fit on the lens one way -- slip it on the front and twist until it locks. That will be the correct position. The "petal" hood is designed that way to avoid vignetting.

[sybren]

I disagree with David. Lens hoods block light that hits your lens but isn't part of your photo. When you use a lens hood, your colours are more pure, your blacks become blacker. I always shoot with a lens hood, as there is virtually no downside to using one. The only thing is that there is a bit of plastic or metal protruding from the front of your lens - big deal if that's going to give you better photos.

[kencaleno]

lens protection(combined with lenscap),better contrast,and avoidance of flare from unwanted light sources-It pays to keep lens hoods on for everytime you use the lens.You need a hood for each lens you have.. Ken

[fletch]

The real question has got to be why not use a lens hood?

[LoveDSLR]

Originally Posted by kencaleno

lens protection(combined with lenscap),better contrast,and avoidance of flare from unwanted light sources-It pays to keep lens hoods on for everytime you use the lens.You need a hood for each lens you have.. Ken

Agreed. However some hoods are more effective than others. The best example is the one for both Nikon and Canon 24-70 f/2.8.

If you have a super zoom then the hood is only effective (avoidance of flare) at the wide end.

[sybren]

Originally Posted by LoveDSLR

If you have a super zoom then the hood is only effective (avoidance of flare) at the wide end.

Another reason to stick to lenses with a smaller zoom range (in case the improved optical quality isn't enough ;-) )

[vandergus]

Lens hoods block light that hits your lens but isn't part of your photo.

"Non image forming light" is the best way I've heard it put. As far as a downside, I think dcclark and amberlynn already mentioned it, added bulk. It bothers some people others it doesn't.

The hand shielding works fine when the flare is noticeable, like ghosting, but when the flare is manifested in less obvious ways, like reduced contrast, you may not realize that you need to shade the lens.

[LoveDSLR]

Another reason to use a hood is to impress others with your BIG lens (think Nikon 200 f/2 hood).

[sybren]

Originally Posted by LoveDSLR

Another reason to use a hood is to impress others with your BIG lens (think Nikon 200 f/2 hood).

It may sound lame, but it really helps. If you are in a situation where you want to separate yourself from "Joe Schmoe with a camera" and profile yourself as a true photographer, a lens hood and a body grip work wonders.

Update: Wohoo! My 500th post, I'm a "senior member" now