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Old Dec 3, 2003, 7:17 AM   #1
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Default What does a Lens Hood Do?

I just got my 300D a few weeks back and am a novice when it comes to photography. I picked up a couple of lenses and they both came with lens hoods. I took pictures with and without the lens hood but failed to see any difference. Can I assume that the effects of the lens hood will only be noticed under certain conditions?
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Old Dec 3, 2003, 8:48 AM   #2
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yep. try shooting in afternoon or morning when the sun is low on the horizon and break the cardinal rule of "shoot only with the sun at your back" and you'll see a big difference. Even more so if you're on a beach or something.

If you live in the northern hemisphere a lens hood can be a big help this time of year. There are other circumstances where it will help too, but this one comes to mind because I had flare and glare on some shots I took on a lake one Saturday morning.

On a related note, does anyone have opinions on those generic $5 folding rubber hoods They have at B&H? Is it really worth it to spend the bucks on the dedicated hoods for Canon lenses? I had one for my old Pentax unit and about all I can say bad about it was that eventually the rubber dried out and it tore.
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Old Dec 3, 2003, 1:01 PM   #3
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echaban
Can't say on the generic hoods. Never tried them. I'm interested in the answer, though.

kartracer
If you really want to create lens flare (this is what the hood is there to prevent) here is a great way to do it (I believe this works.)

Take a picture where you're facing the sun, but the sun is just out of the view of the lens. That should create a nice angle where the light can bounce around a bit inside the lens before hitting the sensor (I believe that causes it.) The hood prevents the light from entering the lens bad angles. It should also be said that other things effect lens flare, like having lots of lens elements (therefor zooms are more susceptible to it than primes.)

They also protect the end of the lens from hitting things. Like branches, people's hands when they swing them. They can save you lots of money..

Eric
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Old Dec 3, 2003, 1:58 PM   #4
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Thank you all for your replies. This site is definitly very eduational for novices like me. I'm gonna go and try it out. Thanks.
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Old Dec 4, 2003, 12:16 AM   #5
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I bought one of those soft rubber $5 lens hoods. I was hoping that because they fold back I can stick the lens with hood in my bag. However, when folded back the right thickness is 3/4 of an inch or so. Makes it hard to stick in a tightly fitting bag. Other than that, they work fine.

Barthold

PS L lenses come with lens hood, thus no need to buy one.
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Old Dec 14, 2003, 12:12 AM   #6
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Quote:
Originally Posted by barthold
I bought one of those soft rubber $5 lens hoods. I was hoping that because they fold back I can stick the lens with hood in my bag. However, when folded back the right thickness is 3/4 of an inch or so. Makes it hard to stick in a tightly fitting bag.
Most of the Canon hoods will screw on the lens in reverse. That adds to the overall diameter, but might solve your problem.

-jb
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Old Dec 14, 2003, 10:11 PM   #7
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Default Lens hood basics

A lens hood is supposed to cut off stray light from entering a lens and causing flair in the photo. This means the hood must be a different length for each focal length since the angle of view is different for each lens. In most cases this is a strong arguement for using the hood provided by the manufacturer for a specific lens. However, I see two exceptions to this rule.

First Zoom lenses are hard to fit with a useful hood. To be correct, the hood needs to get longer when zoomed to longer focal lengths and shorter to avoid vignetting at wider settings. The proper length is just short of where it would vignette. Hoods provided with a 28-300 lens have to be useable at 28mm which means they are so short that they will be next to useless with the lens zoomed to 300mm.

The second question I see is that hoods provided by Canon with 'L' lenses have to assume that you will be using that hood with a film camera but it really could be longer when used on the smaller digital format. In that case, it might be better to put a hood for a 300mm lens on a 200mm used on digital.

I suppose everyone knows that it is common practice for hoods for wide angle lenses to have cut outs at the corners so it can be longer in the sides and do as much good as possible. I believe the fact is that most people are using hoods considerably too short for the lens in use but that is better than too long. Whether the hood is made of black metal, plastic or rubber should mean nothing as long as it is non reflective and the right length. The problem with those generic rubber hoods is not the hood but the fact that people use them on lenses the wrong length. There isn't much demand for hoods as an aftermarket item so those interested in customizing their hoods will probably have to do some fabricating.

I have never heard of anyone offering an adjustable hood for zooms and I have not seen references to how to figure the proper length of a hood for a given lens. The answer would seem to be to try progressively longer hoods until you vignette and then back off. The vignetting will be worst at smallest aperture so don't test this wide open!

Does anyone disagree with any of these points on hoods?
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Old Dec 15, 2003, 11:36 AM   #8
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Doug,
Some people adapt the medium format caqmera bellows lens shades to 35mm cameras. This arrangement is cumbersome but serves the purpose of an adjustable lens hood but not for me.
Sometimes I use a hand , a hat or other nearby object or person to shade the camera lens under difficult conditions.
Ted
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Old Dec 15, 2003, 12:15 PM   #9
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Default hand or hat

Quote:
Originally Posted by twcoffey
Sometimes I use a hand , a hat or other nearby object or person to shade the camera lens under difficult conditions.
Ted
Agree totally! The whole point is to limit the light entering the lens to that part that will make a good image and excluding the part that will make flair. Whether you do it with a custom lens hood or your carefully placed hand makes no difference. Like so many things in photogaphy, it is not how you do it as much as that you found a way that worked for that circumstance. Too many of us blaim the shortcomings of our images on the lack of equipment but more often it is for lack of our imagination.
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Old Dec 17, 2003, 5:00 AM   #10
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Kartracer,

Check out this page on lens flare:

http://www.adorama.com/catalog.tpl?op=article_012703
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