Query Re Lens SIzes

Discussion in 'Digital Photography' started by BF, Jul 4, 2005.

  1. BF

    BF Guest

    Hi

    Im looking to buy a Canon 350D but I have no idea as to what the lens
    sizes mean and what zoom range they relate to.

    For example, one of the lenses that comes with the 350D is 18-55mm and
    there is also a 55-200mm.

    In terms of the zoom range, how do I work it out?

    If I wanted 12x optical zoom, what lens size would that require?

    Thanks for any help.
     
    BF, Jul 4, 2005
    #1
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  2. BF

    Jim Guest

    "BF" <> wrote in message
    news:...
    > Hi
    >
    > Im looking to buy a Canon 350D but I have no idea as to what the lens
    > sizes mean and what zoom range they relate to.
    >
    > For example, one of the lenses that comes with the 350D is 18-55mm and
    > there is also a 55-200mm.
    >
    > In terms of the zoom range, how do I work it out?
    >
    > If I wanted 12x optical zoom, what lens size would that require?
    >
    > Thanks for any help.

    18-55 means that the zoom range of the lens is from 18mm to 55mm.
    55-200 means that the zoom range of the lens is from 55mm to 200mm
    As for the second question, first determine what you want the minimum focal
    length to be.
    Then multiply that value by 12. The result is the longest focal length.
    You won't find many 12x zoom lenses for the 350D.
    Jim
     
    Jim, Jul 4, 2005
    #2
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  3. BF

    Darrell Guest

    "Jim" <> wrote in message
    news:wV%xe.630$...
    >
    > "BF" <> wrote in message
    > news:...
    >> Hi
    >>
    >> Im looking to buy a Canon 350D but I have no idea as to what the lens
    >> sizes mean and what zoom range they relate to.
    >>
    >> For example, one of the lenses that comes with the 350D is 18-55mm and
    >> there is also a 55-200mm.
    >>
    >> In terms of the zoom range, how do I work it out?
    >>
    >> If I wanted 12x optical zoom, what lens size would that require?
    >>
    >> Thanks for any help.

    > 18-55 means that the zoom range of the lens is from 18mm to 55mm.
    > 55-200 means that the zoom range of the lens is from 55mm to 200mm
    > As for the second question, first determine what you want the minimum
    > focal
    > length to be.
    > Then multiply that value by 12. The result is the longest focal length.
    > You won't find many 12x zoom lenses for the 350D.
    > Jim
    >

    The only item that seems to be marked correctly are binoculars 7x50 means
    just that 7 power 50mm objective lens. Every day I have to convince people
    that a 12X zoom on a Canon S2 or Panasonic FZ5 is not 12 power.
     
    Darrell, Jul 4, 2005
    #3
  4. BF

    Jim Townsend Guest

    BF wrote:

    > Hi
    >
    > Im looking to buy a Canon 350D but I have no idea as to what the lens
    > sizes mean and what zoom range they relate to.
    >
    > For example, one of the lenses that comes with the 350D is 18-55mm and
    > there is also a 55-200mm.
    >
    > In terms of the zoom range, how do I work it out?
    >
    > If I wanted 12x optical zoom, what lens size would that require?
    >
    > Thanks for any help.



    http://www.shortcourses.com/choosing/lenses/10.htm
     
    Jim Townsend, Jul 4, 2005
    #4
  5. BF

    Darrell Guest

    "BF" <> wrote in message
    >news:...
    > Hi
    >
    > Im looking to buy a Canon 350D but I have no idea as to what the lens
    > sizes mean and what zoom range they relate to.
    >
    > For example, one of the lenses that comes with the 350D is 18-55mm and
    > there is also a 55-200mm.
    >
    >>> In terms of the zoom range, how do I work it out?


    Something like a Tamron 18~200 is close at 11.11x. I feel the lenses should
    be marked as a ratio like 12:1 instead of 12x. If we had a lens marked as 6X
    zoom that can be a 35~210, but then a 28~168mm or a 50~300mm would all be 6X
    (6:1 ratios)

    Getting back to the Tamron 18~200mm with a 11.11X zoom that will give an 4X
    image magnification...
     
    Darrell, Jul 4, 2005
    #5
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