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Stupid question about shutter speed...

Discussion in 'Olympus Cameras' started by txbkst, Nov 17, 2012.

  1. txbkst

    txbkst Mu-43 Regular

    Nov 9, 2012
    Hi Everyone,
    I am trying to teach myself the ins and outs of using the camera in manual mode. I know the little box in the bottom left is the shutter speed, but when I read about shutter speeds online I see them referenced as 1/25, etc. Does that correspond to the value of 25 on the EPM1 (there is no 1/)?
  2. dhazeghi

    dhazeghi Mu-43 Hall of Famer Subscribing Member

    Aug 6, 2010
    San Jose, CA
    Correct. Many cameras do away with the 1/ part.

    Note that for shutter speeds longer than a second, the E-PM1 uses " to indicate seconds, so 25 = 1/25 second, but 25" = 25.0 seconds.
  3. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Yes the notation is 1/x and if you see x" it is a seconds.
  4. txbkst

    txbkst Mu-43 Regular

    Nov 9, 2012
    Thanks for the quick response!
  5. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    Yes. (BTW- There are no stupid questions.)

    The number to the right is the F-Stop/aperture which is also a single digit but is actually a ratio of lens' focal length to the size of the aperture's opening. (So if the F-Stop is shown as "8" it is actually 1:8.)

  6. Crdome

    Crdome Mu-43 Hall of Famer Subscribing Member

    Sep 11, 2011
    West Central Indiana
    Full seconds are followed by ("), ie: 8 sec = 8"
  7. RevBob

    RevBob Super Moderator Subscribing Member

    Jun 4, 2011
    NorthWestern PA
    The only stupid question is the one you fail to ask - folks here are always glad to help. :cool: 
  8. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    Correct mostly.

    The apertures of photographic lenses are, by convention, almost always calibrated in units expressing the ratio of the focal length of the lens compared to the diameter of the opening. In standard mathmatical formulas relating to optics focal length is always represented by a lower case "f". Therefore "f/stop" is correct and using a hyphen instead of the slash, omitting the punctuation, and using a capital "F" are all incorrect (possible exceptions are to capitalize the "F" when it is the first letter in a sentence or occurs in an English language title).

    Since the f/stop numbers are fractions, f/2 is a "large" or "wide" aperture and f/16 is a "small" aperture. Keep in mind that you will all too often read a post where someone reverses the "large" and "small" terms out of ignorance.

    Like the common shutter speed display or dial that only shows the fraction's denominator (the number after the "/" in fraction notation or after the ":" in ratio notation) almost all f/stop displays and f/stop rings only show the denominator (e.g. "8" for "f/8"). It is also convention that the more technical markings indicating the lens' focal length and maximum aperture use ratio notation ("1:4" instead of "f/4") for the aperture.
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