How can I tell what lens 'spec' is 'wide angle'?

Discussion in 'Digital Photography' started by Steve, Jun 5, 2005.

  1. Steve

    Steve Guest

    How do interpret the figures given for lenses i.e. 28mm-114mm in conjunction
    with zoom, f factor etc to gauge whether a camera has a good wide or poor
    narrow field of view? I would rather know what width of view the camera
    would take at what distance as these figures are meaningless to me - unless
    someone can explain?!
    Steve, Jun 5, 2005
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  2. You are right. Without all the information it is meaningless.

    Even the same lens on different cameras can give different results.

    The usual 7X or 3X or ?X just means that the most telephoto view will
    look 7 or 3 or ? times closer than the wide setting. It does not tell you
    if the lens is wide angle, telephoto or spans both.

    I suggest you give us some more information about exactly why you asked
    the question (like you are ready to buy a new camera and want to know if the
    Acme 5000 model will work well with sports shots of your kids baseball games
    and also the family around the Christmas dinner table.
    Joseph Meehan, Jun 5, 2005
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  3. Steve

    Jim Guest

    I assume these terms are the "35mm equivalent focal lengths". All focal
    lengths shorter than 50mm are considered wide angle even though the normal
    lens for the 35mm format should be about 44mm.
    The shorter the focal length, the more pronounced the wide angle effect is.
    Thus 28mm focal length is a useful wide angle lens.
    The 114 mm setting is a very moderate telephoto setting. You will find that
    this focal length can make excellent portraits.
    Jim, Jun 5, 2005
  4. Steve

    dylan Guest

    You will get the angle of view from the focal length (in your example the
    28-114mm) but this has to be related to the size of the sensor eg 35mm.
    In most cases they will normally quote relative to 35mm cameras as these are
    Take a look at
    for an example where they will quote the angle of view for the 28-135mm lens
    for a 35mm camera. The largest angle being the 28mm setting.
    In 35mmm terms Wide angle is usually around 28mm or less, <20mm will be very
    wide. >100mm is telephoto

    the f number has no effect on angle of view and the zoom just gives the
    range ie 28-135 had a zoom range of 135/28 = 4.8x
    dylan, Jun 5, 2005
  5. You can't tell whether it is wide angle from the focal length
    alone - yiou also need to know what size the imager is.

    f=28mm is wide angle on a camera using 135-film (aka. "full frame),
    it is darned closed to "normal" on a consumer digicam such as the
    Canon EOS 20D, and 28mm gives the FOV of a telephoto lens on a compact
    such as the Canon Powershot G5.
    This web page show you how to compute FOV if you know the focal
    length and imager size:
    Gisle Hannemyr, Jun 6, 2005
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