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Thread: New to EV's

  1. #11

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    ASA film speed is a numerical value describing the light sensitivity of the film.

    Exposure value is INDEPENDENT of film speed and expresses various combinations of shutter speed and aperture as a single numerical value.

    The Kodak Pony has its aperture marked in EV as a “simplification” for easier amateur use. At least that was the idea. It works on the Pony because it only has a single fixed shutter speed. With a camera with a variety of different shutter speeds, the idea of marking the aperture with EV numbers is impractical.

    Once you select a particular film, you have set the film speed. Now both the film speed (its sensitivity to light) and the shutter speed (1/60 second) are fixed. Each data card for the Pony was made to correspond to the film speed of a common Kodak film in use at the time the camera was made.

    All the user had to do was read the sky lighting conditions on the card to find the corresponding EV and set that value on the aperture ring.

  2. #12

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    So, if I understand this correctly, EV tabels are set at ASA 100. If I want to shoot at ASA 200 I add 1 to that EV. So, if I want to shoot EV 14 at 100 ASA, then EV is 14, then if i want to shoot ASA 200 at EV 14, I need to bump it up to EV 15. When the EV value is changed, the f stop will no longer be f/16 but f/22.
    Last edited by zackesch; 11-06-2012 at 01:10 PM. Click to view previous post history.

  3. #13
    Steve Smith's Avatar
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    EV - Exposure Value is a function of shutter speed and aperture only.

    LV - Light Value is a measure of the light only.

    At ISO 100 these numbers coincide. e.g. for ISO 100, an LV reading of 15 means you should use an EV setting of 15.

    At ISO 200, half as much light is needed so an LV reading of 15 will require an EV setting of 16.


    Steve.

  4. #14

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    Clearly stated, Steve!

  5. #15
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    Quote Originally Posted by Steve Smith View Post
    At ISO 100 these numbers coincide. e.g. for ISO 100, an LV reading of 15 means you should use an EV setting of 15.

    At ISO 200, half as much light is needed so an LV reading of 15 will require an EV setting of 16.
    And since the camera doesn't have an EV setting of 16, there is a problem! Stay in the shade!

  6. #16

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    Ok, I have a good understanding of it now. Thanks for your time.

    I noticed that hatchetman, no indoor shots with 200 ISO, and with overcast starting to be normal, Im not too worried about anything over EV 15.

  7. #17
    Steve Smith's Avatar
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    I wouldn't worry about over exposing one or two stops!


    Steve.

  8. #18
    Hatchetman's Avatar
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    Quote Originally Posted by Steve Smith View Post
    I wouldn't worry about over exposing one or two stops!
    Good point. Digital habits are hard to break.

  9. #19

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    Now I have some more photo info that I can entertain my wife with. After all, shes showing interest in B&W film.
    Ill start compairing the weather to an EV value, like looking out my window its now about EV 12. I'm sure she will love that.

  10. #20
    Steve Smith's Avatar
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    No!!!


    You compare it with an LV level!!


    Steve.

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