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08/10/2010 10:43:45 PM · #1 |
What kind of lens hood do I want?
Round? Flower Petal?
What do I look for?
Im clueless! so fill me in!
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08/10/2010 10:54:46 PM · #2 |
| I've always just gotten whatever the manufacturer makes for a given lens... |
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08/10/2010 10:54:47 PM · #3 |
You want the lens hood that is designed for the lens. Depending on the focal length, zoom length, ect. each will have it's own design. Look up your lens on B&H and at the bottom it will tell you what lens hood is suppose to be with it.
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08/10/2010 11:05:10 PM · #4 |
I did a search for my soon to be here lens.... and there was a zillion different kinds
I just bought a Canon EFS 55-250mm 1:4-5.6 IS
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08/10/2010 11:07:40 PM · #5 |
Since we shoot rectangular images with a round lens, in theory a cylindrical lens hood is sacrificing coverage on two sides. In theory, a petal hood is needed for perfect coverage, but it has to be designed for your particular lens.
On fixed-focal-length (prime) lenses, once you get out to around 75mm or so there's no real advantage to be gained from a petal hood. On the other hand, in the ultrawide range a lens hood that is NOT of the petal design is literally useless.
When you're talking about zoom lenses, it gets more complicated; obviously, whatever hood you use has to NOT vignette at the widest end of the zoom, meaning that its coverage is not as good as it could be at longest end. On a lens like a 70-200mm, this really isn't an issue. On a lens like a 24-70mm, you're really giving up a little more than you'd like to at the long end, but that's the price you pay. On the ultrawide zooms, the lens hood is of some slight utility at 10mm, but essentially meaningless at 22mm.
That's my take on it, anyway :-)
R.
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08/10/2010 11:08:05 PM · #6 |
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08/10/2010 11:10:42 PM · #7 |
Originally posted by Bear_Music:
Since we shoot rectangular images with a round lens, in theory a cylindrical lens hood is sacrificing coverage on two sides. In theory, a petal hood is needed for perfect coverage, but it has to be designed for your particular lens.
On fixed-focal-length (prime) lenses, once you get out to around 75mm or so there's no real advantage to be gained from a petal hood. On the other hand, in the ultrawide range a lens hood that is NOT of the petal design is literally useless.
When you're talking about zoom lenses, it gets more complicated; obviously, whatever hood you use has to NOT vignette at the widest end of the zoom, meaning that its coverage is not as good as it could be at longest end. On a lens like a 70-200mm, this really isn't an issue. On a lens like a 24-70mm, you're really giving up a little more than you'd like to at the long end, but that's the price you pay. On the ultrawide zooms, the lens hood is of some slight utility at 10mm, but essentially meaningless at 22mm.
That's my take on it, anyway :-)
R. |
uhhhhh lol can you explain that in kid terms. it went wooosh over my head... though it could be im tired.
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08/10/2010 11:18:25 PM · #8 |
On the kit lens, you can't use a petal hood. Because the outer lens element rotates, you will get the petals sticking into the image at certain spots in it's rotation. (I bought one once and realized my mistake pretty quickly) I bought a screw in collapsing rubber hood for mine. Something like this one for $5 If you want the hood to provide a little more physical protection, you can get a plastic one like this.
Notice that on a short lens, the hood is not very deep. If it were as deep as the one I linked below, the hood would be visible in the frame on the short end of the focal range. So, you end up only getting some minor benefit on the shorter lenses.
Here's what I bought for the 55-250 lens, that I have and you have coming.
Message edited by author 2010-08-10 23:20:06. |
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08/10/2010 11:22:23 PM · #9 |
Originally posted by JustCaree:
uhhhhh lol can you explain that in kid terms. it went wooosh over my head... though it could be im tired. |
If you put a paper towel tube, or something like it, long and round, onto the end of your lens, it will "vignette" the image by restricting to a very narrow angle the light coming in. The lens itself is trying to see a specific angular coverage; the longer or more tele the lens, the narrower the angle it sees. My 17mm WA on the 5D sees like 105 degrees from edge to edge diagonally, a 200mm lens on the same camera sees about 12 degrees diagonally.
So obviously the more telephoto lens can have a deeper lens shade tube without it truncating the image, see?
Slightly harder to visualize is that the angular coverage on the long dimension of our image is different from the angular coverage on the short dimension; that 200mm lens on a FF camera is around 12 degrees diagonally, but 7 vertically and 10 horizontally. A superwide, say 15mm, on FF shows coverages of 111, 77, and 100 respectively.
Thus the petal hoods on WA lenses; they are essentially custom-tailoring the hood to the rectangular format, they are a little deeper on the long side than on the short side. But the hoods that come with a WA zoom have to not vignette at the widest zoom, so they are not very effective hoods at the narrowest zoom.
R.
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08/10/2010 11:23:05 PM · #10 |
Originally posted by Yo_Spiff:
On the kit lens, you can't use a petal hood. Because the outer lens element rotates, you will get the petals sticking into the image at certain spots in it's rotation. (I bought one once and realized my mistake pretty quickly) I bought a screw in collapsing rubber hood for mine. Something like this one for $5 If you want the hood to provide a little more physical protection, you can get a plastic one like this.
Notice that on a short lens, the hood is not very deep. If it were as deep as the one I linked below, the hood would be visible in the frame on the short end of the focal range. So, you end up only getting some minor benefit on the shorter lenses.
Here's what I bought for the 55-250 lens, that I have and you have coming. |
ok if i end up upgrading to the 18-55 is would this be smarter cause it works on both the 55-250 and the 18-55 and its a petal? or would the one you got be better and then find one similar for the 18-55is
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08/10/2010 11:24:24 PM · #11 |
Originally posted by Bear_Music:
Originally posted by JustCaree:
uhhhhh lol can you explain that in kid terms. it went wooosh over my head... though it could be im tired. |
If you put a paper towel tube, or something like it, long and round, onto the end of your lens, it will "vignette" the image by restricting to a very narrow angle the light coming in. The lens itself is trying to see a specific angular coverage; the longer or more tele the lens, the narrower the angle it sees. My 17mm WA on the 5D sees like 105 degrees from edge to edge diagonally, a 200mm lens on the same camera sees about 12 degrees diagonally.
So obviously the more telephoto lens can have a deeper lens shade tube without it truncating the image, see?
Slightly harder to visualize is that the angular coverage on the long dimension of our image is different from the angular coverage on the short dimension; that 200mm lens on a FF camera is around 12 degrees diagonally, but 7 vertically and 10 horizontally. A superwide, say 15mm, on FF shows coverages of 111, 77, and 100 respectively.
Thus the petal hoods on WA lenses; they are essentially custom-tailoring the hood to the rectangular format, they are a little deeper on the long side than on the short side. But the hoods that come with a WA zoom have to not vignette at the widest zoom, so they are not very effective hoods at the narrowest zoom.
R. |
ahhhh ok that makes sense.... sounds like petal is better if i do a lot of long range.... round is better for short range...
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08/10/2010 11:31:00 PM · #12 |
Originally posted by JustCaree:
like petal is better if i do a lot of long range.... round is better for short range... |
Not really, though I'm not sure exactly what you mean. A couple points:
1. If the front element of the lens rotates when you focus, you can't use a petal hood at all. It only works for lenses with internal focusing.
2. Whether you need a petal hood or not is more a function of focal length; at the wide end, they are pretty much the only useful hoods. At the longer end, it doesn't really make any difference. The cutoff point is like around 70mm; past that point, it doesn't matter, really. So the 55-250mm is gonna be fine with the appropriate cylindrical hood for the 55mm end of the zoom. It's not as much hood as you'd want at 250mm, but there's not a lot you can do about that. With the 18-55mm, IF the front element is fixed, the appropriate petal hood is the way to go.
R.
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08/10/2010 11:31:57 PM · #13 |
Originally posted by JustCaree:
ok if i end up upgrading to the 18-55 is would this be smarter cause it works on both the 55-250 and the 18-55 and its a petal? or would the one you got be better and then find one similar for the 18-55is |
The petal hood will be in the frame at the short end of your 18-55. A petal hood is useful on a short focal length lens that does NOT have a rotating front element. The kit lens rotates. |
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08/10/2010 11:33:44 PM · #14 |
Think about it as if you were going to have two pairs of goggles made, one pair for wide angle, and another for telephoto.
The wide angle ones would need to be petal types and shallow so that you could see more from side to side.
The telephoto ones would look like toilet paper tubes, because with telephoto you only see a small area straight ahead.
For wide angle *small MM number* you use a wide or petal shade.
For telephoto * large MM number* you would use a longer, narrower shade.
For a zoom, the shade has to be made for the widest setting so that it does not cover the area that the lens is trying to "see" and make dark edges when it is set to it's widest setting.
The purpose of the lens shade is to keep stray light from hitting the front element of the lens and causing loss of contrast and flares/ghosts from bright lights just outside the "view" of the lens.
ETA, also ditto what Yo said. With a lens which rotates at the front end when you focus or zoom, a petal shade is not practical, only a round one will be satisfactory.
Message edited by author 2010-08-10 23:36:24.
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