What's the deal with lens hoods?

I've been shooting SLRs as a hobby for about 7 years now...first on a

Canon Rebel G, and in the past month, I have switched to a Nikon D70.

With the Canon, I never bothered to use lens hoods, as I didn't know

what they were used for and never really cared to investigate.

 

But since getting the D70 and joining this site, I've become curious.

I have the 18-70 D70 kit lens and the Nikkor 70-300 ED lens.

 

So my questions are...what is the purpose of the lens hood? Does it

really improve performance, and if so, how? Also, if you do recommend

using the hood, should I use it all the time on both lenses, or only

under certain conditions?

 

Basically, this is a general, what the heck is a lens hood used for

anyway type of question.

 

Any help will be greatly appreciated. Thanks.

Lens hoods are used to prevent flare - stray light getting into the lens which might cause haze and reduce contrast. Important when shooting in situations when you have bright light falling at an angle on the lens surface. Must you use one - no. But you must know which situations might call for one - then even the palm of your hand would do.

Hoods are the most useful when shooting towards a bright light source (the sun). They can

reduce lens flair but more importantly they can increase contrast in those situations. You can

get the exact same effect by using your hand or arm to shade the lens when light is falling

directly on the front element. That's what I tend to do. I shade it with my hand and I can

usually see right through the viewfinder when shade is needed.

 

I'm sure that others will have more detailed advice/information.

The hood helps protect the lens, too. I dropped my 85mm 1.8 off a counter on a tile floor and it hit hard enought to dent the metal hood. Without it, I'm sure the glass would have cracked. It also helps keep some distance between the front element of the lens and things that might scratch it, etc. (i.e., it's a harder to get your thumbprint in the middle of the glass with hood on.)

In other words, if you can have the hood attached all the time? use it. It will protect your lens from a lot of things like in case it is dropped, your fingers might be hard to get into the lens with a hood on, also any branches or stuff that might be around you, you never know.

 

The main purpose for a lens hood is to cover it from flare. Lights from different directions might hit your glass and cause this flare. So with this hood your glass only sees the only light that is supposed to see, forward.

...sometimes even ambient light might cause minimum amounts of flare, this is why I'd recommend to use it all the time, you will get the best possible results from your lens.

1) Reduce/eliminate flare

 

2) Protect the front element from physical/environmental contact (good to keep light rain off)

 

3) Makes a lens look bigger. The Nikon 500mm is very impressive with its extra long hood attached. :)

Make it look bigger...lol. That's what its all about, isn't it?

 

Thanks for the quick responses guys. That's what I wanted to know...is it advisable keeping the hoods on at all times while shooting. Sounds like it is.

The only times you should NOT use the hood are 1) when you use the built-in flash (on some camera bodies) and it might block some of the flash and cast a shadow; 2) when the hood might block an AF assist light.

 

Otherwise use a hood whenever possible (even inside) because it provides protection as well as prevents flare and ghosting.

There are no negative effects of using a lens hood (other than blocking a pop-up flash like was already brought up). I use them all the time because you never know when you'll bump into something with the lens (and might guess wrong in a lens flare situation) and this way you'll always be protected. Lenses can still flare with hoods attached, but it will be minimized to some degree.

I've also found that the use of a lens hood is more crucial when using lenses with those bulging, curved front element(eg:85mm 1.4 afd).

 

Just my half a cent?

Other times when a lens hood is not ususlly used: when using a polarizer filter and using ND grads, or filters in a Cokin-type holder. Regardless, make sure your lens hood is firmly attached and does not rattle loose with use. It is cheap insurance for image and exquipment.

You might actually be able to get away without using the 18-70 DX Nikkor without the hood - it's amazingly flare resistant for a zoom. But the hood is so easy to carry because it reverses onto the lens barrel, there's really no reason not to use it.

 

Without the lens hood the 70-300 ED seems a bit prone to veiling flare. Compared with ghosting (readily identifiable iris shapes) this kind of flare can be difficult to identify because it can simply appear as overall low contrast. This lens definitely seems to benefit from using a hood.

It serves the same purpose as a baseball cap does for your eyes in bright sunshine. Does that make sense?

I use the hood to protect he front of the lens so I can leave the protective filter and lens

cap in the lens box for whenever I sell it.

 

Works for me.