Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,555   Posts: 1,545,017   Online: 733
      
Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 40

Thread: Why 160?

  1. #21
    Curt's Avatar
    Join Date
    Sep 2005
    Location
    Pacific Northwest
    Shooter
    Multi Format
    Posts
    4,551
    Images
    15
    To drive you crazy! [It is half the speed of Tri-X 320!]

    Why do olives come packed in salt water and sardines come packed in olive oil?

    Steve
    Why are the labels on Cranberries upside down according to how the can is opened? I have asked many people that and no grocer knows the answer.

    Maybe it goes with ASA 64. I use ASA because that film is long gone. What's the most unusual film speed listed by a manufacturer?

    I love those King Oscar ones. http://www.kingoscar.com/company

    My step grandfather was Norwegian, we fished and hunted and ate King Oscar Sardines, but I've told that story before...

    BTW: where is Ole these days?
    Everytime I find a film or paper that I like, they discontinue it. - Paul Strand - Aperture monograph on Strand

  2. #22
    Jesper's Avatar
    Join Date
    Mar 2009
    Location
    Lund in the south of Sweden
    Shooter
    Multi Format
    Posts
    642
    160 Asa as we think of it today may be strange for us, but it is 23DIN.
    Is 23 more or less logical than 21DIN (that is 100Asa) or 27DIN (400Asa)?

  3. #23

    Join Date
    Aug 2009
    Shooter
    35mm
    Posts
    74
    To make film faster, the sensitivity has to increase exponentially, i.e. one step difference means doubling the sensitivity. In reverse, it decreases logarithmically. A similar thing happens with music. If you look at the neck of a guitar, the frets aren't spaced evenly, they get further apart the further from the body you go.
    100-200-400-800-1600 are the major steps, but each step has half and third steps between it and the next one. Because the scale is exponential, a third of a step isn't 0.33, and changes throughout the step. The difference between 100 and 125 is the same as between (125 and 160) and (160 and 200) and (400 and 500) and (5000 and 6400). These aren't exact figures because the actual figures are horrendous irrational numbers, but 160 is a lot easier to remember than some awful and negligibly different surd.

  4. #24

    Join Date
    Jul 2009
    Location
    Sheffield, UK
    Shooter
    Multi Format
    Posts
    68
    I've always wondered this too...

    And also, I've never (that I can recall) seen ISO 200 120 rolls. Do they exist?

    EDIT: Well explained Mattmoy, makes much more sense to me now!
    Currently shooting: KMZ Horizont and Minox B

  5. #25

    Join Date
    Nov 2008
    Shooter
    35mm
    Posts
    257
    Quote Originally Posted by Mike1234 View Post
    Wouldn't 141 speed be closer to the middle of 100 and 200?
    It would be the exact middle between 100 and 200. But ISO speeds typically go in 1/3 stops rather than 1/2 stops. So you are more likely going to see ISO125 or ISO160 than ISO141.

    Quote Originally Posted by Chris Nielsen View Post
    If clocks go clockwise because of the sundial and sundials run anticlockwise in the southern hemisphere, then clocks down here should run anticlockwise as well, shouldn't they?
    Maybe if clocks were invented in the Southern Hemisphere.

  6. #26
    EASmithV's Avatar
    Join Date
    Aug 2008
    Location
    Maryland
    Shooter
    Multi Format
    Posts
    1,874
    Blog Entries
    4
    Images
    123
    Quote Originally Posted by Blacknoise View Post
    I've always wondered this too...

    And also, I've never (that I can recall) seen ISO 200 120 rolls. Do they exist?

    EDIT: Well explained Mattmoy, makes much more sense to me now!
    What about E200?
    www.EASmithV.com

    "The camera is an instrument that teaches people how to see without a camera."— Dorothea Lange
    http://www.flickr.com/easmithv/
    RIP Kodachrome

  7. #27
    Prest_400's Avatar
    Join Date
    Jan 2009
    Location
    Spain
    Shooter
    Med. Format RF
    Posts
    543
    Maybe 160 is a nicer number than 200.
    Since 160 looks more like 100 than 200, it gives a different thinking about the film; Less grain, more sharpness...

    Just like when prices are 9.95/9.99 instead of 10.

  8. #28
    mts
    mts is offline
    mts's Avatar
    Join Date
    Feb 2004
    Location
    Los Alamos, NM
    Shooter
    Multi Format
    Posts
    335
    Images
    119
    To remind you to rate it at EI-125.
    By denying the facts, any paradox can be sustained--Galileo

  9. #29

    Join Date
    Sep 2009
    Location
    Washington, the state
    Shooter
    Multi Format
    Posts
    1,126
    Images
    16
    Sixty years ago color films used to be ASA 12. Just be glad you have 160.

  10. #30

    Join Date
    Sep 2006
    Shooter
    35mm RF
    Posts
    429
    The Kodak portrait color negative films have slowly gained speed through the years. Ektacolor Professional S (C-22) and Vericolor S (C-41) were ASA 100. Vericolor II Professional S was ASA 125. Vericolor III was 160, as is Portra 160NC (of course). So it gained speed a third-stop at a time over the last 35 years.

    Of course, with Portra, they also added 400 speed films, and later an 800 speed.

Page 3 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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