What does the numbers on the lens tells you? Like 18-200mm


Csboi

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Jul 18, 2011
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#1
As the title says it all, what does the 18 and 200mm means? The bigger the mm behind, means the more it can zoom? Means 500mm can zoom better than 200mm, and how much can it zoom? Thanks :bsmilie:
 

Diluted

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Jun 6, 2010
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#3
As the title says it all, what does the 18 and 200mm means? The bigger the mm behind, means the more it can zoom? Means 500mm can zoom better than 200mm, and how much can it zoom? Thanks :bsmilie:
it simply means 18mm and 200mm is the widest and longest focal length you can get on that lens..
 

edutilos-

Senior Member
Dec 28, 2010
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#4
Zoom is a very artifical concept.

You need to care more about these two things: "focal length" and "field of view". Make that three, also read up about "crop factor".

4x zoom is meaningless, 15-60mm is 4 times zoom, 50-200mm is 4 times zoom, 800-3200mm is 4 times zoom, all it conveys is that you can zoom in 4 times. Not very useful.

Useful links:
http://photo.net/learn/fov/
http://www.photoaxe.com/understanding-the-lens-focal-length-and-aperture/
http://www.outbackphoto.com/dp_essentials/dp_essentials_01/essay.html
http://www.digital-photography-school.com/crop-factor-explained
http://www.kenrockwell.com/tech/crop-factor.htm
 

rhino123

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Sep 1, 2006
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#5
As the title says it all, what does the 18 and 200mm means? The bigger the mm behind, means the more it can zoom? Means 500mm can zoom better than 200mm, and how much can it zoom? Thanks :bsmilie:
18-200mm is the focal lengths of the lens.

18mm is at the wide end and 200mm is at the long ends. It is not correct to say that 500mm can zoom better than 200mm because by just stating 1 figure (500mm or 200mm) it would means the focal lenght is merely 500mm or 200mm.

There is no such thing as better zoom... because all lenses are designed for specific uses. And so there is no better or worst.

For a starter, I would suggest you search the net and read a bit more on the focal length.

1) http://en.wikipedia.org/wiki/Focal_length (this is a good place to start)
2) http://www.dpreview.com/learn/?/key=focal+length
3) http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/foclen.html

There are hundreds more sites.
 

Cowseye

Senior Member
Mar 7, 2010
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#6
edutilos- said:
Zoom is a very artifical concept.

You need to care more about these two things: "focal length" and "field of view". Make that three, also read up about "crop factor".

4x zoom is meaningless, 15-60mm is 4 times zoom, 50-200mm is 4 times zoom, 800-3200mm is 4 times zoom, all it conveys is that you can zoom in 4 times. Not very useful.

Useful links:
http://photo.net/learn/fov/
http://www.photoaxe.com/understanding-the-lens-focal-length-and-aperture/
http://www.outbackphoto.com/dp_essentials/dp_essentials_01/essay.html
http://www.digital-photography-school.com/crop-factor-explained
http://www.kenrockwell.com/tech/crop-factor.htm
I always laugh when I read the gimmick features itemization on PnS on the X times zoom. 1-20mm is 20 times zoom! :p though I dun think it's possible or practical.
 

edutilos-

Senior Member
Dec 28, 2010
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#7
I always laugh when I read the gimmick features itemization on PnS on the X times zoom. 1-20mm is 20 times zoom! :p though I dun think it's possible or practical.
Well, we were all there once, I also remember buying a Sony H2 thinking, "wa, the zoom so much". :)
 

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