Focal length - digital v. 35mm.

Discussion in 'Digital Photography' started by Peter Billinghurst, Sep 3, 2003.

  1. What are the digital equivalent focal lengths to 35mm cameras at, say 24mm,
    85mm and 300mm, or does this depend on the digital camera? If there are
    differences in the angle of view between different digital cameras of the
    same focal length, is there any way of finding this out for a particular
    model?

    Peter
     
    Peter Billinghurst, Sep 3, 2003
    #1
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  2. "Peter Billinghurst" <> writes:

    > What are the digital equivalent focal lengths to 35mm cameras at, say 24mm,
    > 85mm and 300mm, or does this depend on the digital camera? If there are
    > differences in the angle of view between different digital cameras of the
    > same focal length, is there any way of finding this out for a particular
    > model?


    It depends on the camera. For example, my Olympus C-2100UZ lens is a 7-70mm
    lens, but that is equivalent to a 38-380mm lens in a 35mm camera since the
    sensor is much smaller than the 35mm film. Digital SLRs have a crop factor
    that you must multiply the 35mm lens focal length by (for example, the Canon
    10D/300D uses a crop factor of 1.6x, Nikon cameras generally use 1.5x, the
    Canon 1Ds is a full frame camera and uses a crop factor of 1x).

    Generally any place where they list the camera's specs (such as dpreview.com)
    will mention the 35mm equivalent of the lens if it has a builtin lens, or the
    crop factor if it is a DSLR with interchangable lenses.

    --
    Michael Meissner
    email:
    http://www.the-meissners.org
     
    Michael Meissner, Sep 3, 2003
    #2
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  3. Many thanks everyone. It has pointed in a useful direction.

    Peter


    "Peter Billinghurst" <> wrote in message
    news:bj4em7$h7g$...
    > What are the digital equivalent focal lengths to 35mm cameras at, say

    24mm,
    > 85mm and 300mm, or does this depend on the digital camera? If there are
    > differences in the angle of view between different digital cameras of the
    > same focal length, is there any way of finding this out for a particular
    > model?
    >
    > Peter
    >
    >
     
    Peter Billinghurst, Sep 3, 2003
    #3
  4. Peter  Billinghurst

    NJH Guest

    How early do you mean by "early"? :)

    I believe Oskar Barnack's very first Leica (which would be what, about 1923
    or so?) had a 50mm lens, and that remained the "normal" for Leica lenses
    forever. (Disregarding the CL and CLE, of course.)

    Likewise the Zeiss Contax. Zeiss actually did market a 42.5mm lens for the
    Contax in the 1930s, which would be close enough to the traditional
    "normal"--but there was little or no buyer interest in it and it was soon
    dropped.

    Similarly Agfa and other German makers settled on 50mm as normal and they
    remained so into the 1950s. I have a small collection of Agfa Karats from
    that period with various lenses, every one of them a 50mm. Likewise Argus
    and Kodak cameras in this country (and German Kodaks like the Retina series)
    used 50mm as normal up to that time. My very first 35, a dinky little Argus
    A2 (in 1951) had a 50mm lens. So did my next one, a Kodak Retina IIa.

    Kodak did make one 35, the Signet, about that time with a 44mm lens as I
    recall. Also the neat little Bolseys had lenses of that f.l., but outside of
    those two I don't remember any in the early 1950s.

    By the 1960s Agfa and others did move to 45mm normal lenses and of course by
    then there were a flood of Japanese RF 35s with 45mm lenses too.

    As for 55mm (and 58mm) lenses, those only came with SLRs, and the only
    reason for them was that the longer f.l. was necessary with fast lens
    designs of that time to give the mirror room to swing. Exaktas usually came
    with the 58mm f/2 Zeiss Biotar as I recall. It wasn't that they WANTED
    normal lenses of that f.l. (which was actually very close to the traditional
    "portrait" lens), they just had to make 'em that long to get a six-element
    lens onto an SLR.

    Neil


    "Don Stauffer" <> wrote in message
    news:...
    > Many early 35s had lenses in 45 to 48 mm range. Then 50 seemed to
    > become almost a standard, though a few supplied 55mm as normal.
    >
    > NJH wrote:
    >
    > >
    > > You're correct that the "normal" lens has traditionally been considered

    a
    > > lens with a f.l. equal to the diagonal of the negative. But the diagonal

    of
    > > a full-frame 35mm negative is about 43.2 mm. The "normal" 50mm lens has
    > > always been on the longish side.
    > >
    > > Neil
    > >
    > > > --
    > > > Thor Henning Wegener
    > > >
    > > > http://home.online.no/~wegener
    > > >
    > > >

    >
    > --
    > Don Stauffer in Minnesota
    >
    > webpage- http://www.usfamily.net/web/stauffer
     
    NJH, Sep 5, 2003
    #4
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