Wide angle and telephoto

Discussion in 'Digital Cameras' started by Peter Billinghurst, Dec 3, 2003.

  1. Canon advertises x.5 and x2 lenses for the Powershot G3. What does this
    mean? Would it be correct to say that a x.5 lens will double the dimensions
    (both width and height) of the area pictured and the x2 lens would halve the
    dimensions?

    Or to put it another way, what effect do these lenses have on the focal
    length of the lens? I assume that 35mm would become 17.5mm with wide angle
    and 140mm would become 280mm.

    Any advise would be welcome. Thanks

    Peter
     
    Peter Billinghurst, Dec 3, 2003
    #1
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  2. Peter  Billinghurst

    Aardvark Guest

    Yes. The x0.5 will halve your focal length ( so your G3 is now a
    17.5-70mm ) and the x2 will double your focal length ( 70-280 ).
    However, at many focal lengths, there will be severe vignetting,
    which means that only SOME focal ranges can be used when the
    converters are attached. The usable focal lengths are usually at
    the wide end for the x0.5, and at the telephoto end for the x2.
     
    Aardvark, Dec 3, 2003
    #2
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  3. Many thanks - would the first part of my mail concerning dimensions also be
    correct?

    Peter
     
    Peter Billinghurst, Dec 3, 2003
    #3
  4. Many thanks for this - Canon do advertise such a converter on their web
    site. Also several other accessories for the G3.

    I do actually have both converters, but made by an outfit named Digital
    Optics. While the glass seems to be very good, the magnifications or
    conversion factors are nothing like x.5 or x2 as advertised: more like .77
    for the wide angle and 1.2 for the telephoto. I am just checking on the
    facts before complaining!

    Once again thanks



    Peter
     
    Peter Billinghurst, Dec 4, 2003
    #4
  5. Yes - come to think, one would hardly expect a conversion right down to
    f17.5 to work very well. I will put in another post to ask whether any one
    has experience of the Canon tele converter.

    Thanks again

    Peter
     
    Peter Billinghurst, Dec 4, 2003
    #5
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