Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,506   Posts: 1,543,487   Online: 1045
      
Results 1 to 8 of 8

Thread: f/stops

  1. #1
    SLNestler's Avatar
    Join Date
    Sep 2002
    Location
    Coral Springs, FL
    Shooter
    Large Format
    Posts
    101

    f/stops

    Hi.
    Does anyone out there know what "f" stands for in f/stop?
    I saw it once in an obscure book, and can't find it again.
    It's one of the most used terms in photography, but I can't find its derivation again.
    I know it's a French word, but since my French vocabulary was learned from Miss Piggy, I'm stumped.
    Thanks.
    Steven
    Steven Nestler
    http://stevennestler.com

  2. #2
    VoidoidRamone's Avatar
    Join Date
    Aug 2004
    Location
    New York City
    Shooter
    Multi Format
    Posts
    490
    I always thought the "f" stood for focal length
    -Grant

  3. #3
    glbeas's Avatar
    Join Date
    Sep 2002
    Location
    Roswell, Ga. USA
    Shooter
    Multi Format
    Posts
    3,307
    Images
    109
    You'll find reference in past postings in the forums. It refers to the optical diameter of the aperture expressed as fraction of the focal length. As in an f/2 50mm lens has an aperture 25mm in diameter, a 100 mm f/2 has a 50mm diameter one. The reason for using this system is both f/2 lenses transmit the same amount of light even though the apertures are different sizes. Keeps life simple for the photog.
    Gary Beasley

  4. #4

    Join Date
    Dec 2004
    Location
    Milwaukee, Wi
    Shooter
    35mm
    Posts
    3,242
    F stands for fractional.

  5. #5
    Ed Sukach's Avatar
    Join Date
    Nov 2002
    Location
    Ipswich, Massachusetts, USA
    Shooter
    Medium Format
    Posts
    4,520
    Images
    26
    "f" (lower case) is standard for "focal length". "f/stop" indicates an aperture diameter that is "focal length" divided by whatever denominator. With a focal length of 50 mm, the aperture diameter represented by f/2, given a 50mm lens, is 50mm/2, or 25mm.

    Note that "f" refers to the actual focal length at the moment, not necessarily at infinity. If a lens is extended to say 75mm for close focusing, the "f/stop" value in the above example changes to 75mm/25 (aperture diameter), or f/3.
    Carpe erratum!!

    Ed Sukach, FFP.

  6. #6

    Join Date
    Sep 2004
    Shooter
    Multi Format
    Posts
    343
    Quote Originally Posted by SLNestler
    Hi.
    Does anyone out there know what "f" stands for in f/stop?
    I saw it once in an obscure book, and can't find it again.
    It's one of the most used terms in photography, but I can't find its derivation again.
    I know it's a French word, but since my French vocabulary was learned from Miss Piggy, I'm stumped.
    Thanks.
    Steven
    I like Claire's explanation, but I think the the word you are thinking of is "fenetre" or window (here misspelled 'cause I am not savvy enough to get "^" to appear in the middle of the word). Similarly I was once told that it was derived from the latin word fenestra. ...if death by beheading is decapitation and death by being pitched out a window is defenestration, is the unconcious clipping of heads through poor framing deparallaxation?
    Celac.

  7. #7
    Helen B's Avatar
    Join Date
    Jul 2004
    Location
    Hell's Kitchen, New York, USA
    Shooter
    Multi Format
    Posts
    1,557
    Images
    27
    I agree with Grant and Ed - f is 'focal length'. The denominator is the diameter of the entrance pupil.

    And is a decimetre something that's been dug out of a cemetery?

    Best,
    Helen
    PS ê might be Alt+0234?

  8. #8

    Join Date
    Oct 2003
    Location
    Århus, Denmark
    Shooter
    Medium Format
    Posts
    2,102
    Images
    16
    Hmmm...another "f" word



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin