Using EV adjustment to get more light at night ?

Discussion in 'Digital Photography' started by Povl H. Pedersen, Dec 20, 2003.

  1. If I take my camera (EOS 300D) set it for 1600 ISO and
    som fixed exposure time, and does not have enough light,
    can I just adjust the EV to +2 and gain more light that
    way ? Or is there something wrong doing so ?

    I.e. set the exposure time to 1/60 second, ISO 1600,
    EV +2 ? Assuming already outside where AE will work ?

    If I am in P mode, and adjust EV, then it does so by
    increasing shutter time. And in T-mode it adjusts the
    Aperture. So it is my guess, that it will not work.

    Can I extract more light from the 12-bit RAW images ?
    I know some of the extra bits are used for highlight,
    since you can save some overexposure.
     
    Povl H. Pedersen, Dec 20, 2003
    #1
    1. Advertising

  2. Povl H. Pedersen

    DHB Guest

    You guessed correctly!

    Exposure compensation does not work in full manual mode because you are
    selecting both shutter speed & aperture. In most other modes it will
    calculate what "it thinks" is the "correct" exposure settings & than add or
    subtract "your" EV setting from that.

    As for your question about RAW mode I am still in the learning curve
    with it so I can't offer much. My understanding is that RAW mode is a
    "little" more forgiving of improper exposure only because the camera did not
    process the image DATA. But exposure is important to get correct regardless
    of what format the picture DATA is saved in, jpg, TIFF or RAW.

    If I am wrong I am sure somebody will correct me & then we will both
    learn something.

    Respectfully, DHB

    "Povl H. Pedersen" <> wrote in message
    news:...
    > If I take my camera (EOS 300D) set it for 1600 ISO and
    > som fixed exposure time, and does not have enough light,
    > can I just adjust the EV to +2 and gain more light that
    > way ? Or is there something wrong doing so ?
    >
    > I.e. set the exposure time to 1/60 second, ISO 1600,
    > EV +2 ? Assuming already outside where AE will work ?
    >
    > If I am in P mode, and adjust EV, then it does so by
    > increasing shutter time. And in T-mode it adjusts the
    > Aperture. So it is my guess, that it will not work.
    >
    > Can I extract more light from the 12-bit RAW images ?
    > I know some of the extra bits are used for highlight,
    > since you can save some overexposure.
     
    DHB, Dec 21, 2003
    #2
    1. Advertising

  3. Povl H. Pedersen

    Guest

    Povl H. Pedersen <> wrote:
    > If I take my camera (EOS 300D) set it for 1600 ISO and
    > som fixed exposure time, and does not have enough light,
    > can I just adjust the EV to +2 and gain more light that
    > way ? Or is there something wrong doing so ?


    The nice thing about digital cameras is that once you already
    own one, it costs nothing to experiment with the camera's
    different features. Try adjusting the EV and see how it works
    out for you. At worst, you'll end up with a black photo and
    you can easily delete it and try other settings.
     
    , Dec 21, 2003
    #3
  4. "Povl H. Pedersen" <> writes:
    >If I take my camera (EOS 300D) set it for 1600 ISO and
    >som fixed exposure time, and does not have enough light,
    >can I just adjust the EV to +2 and gain more light that
    >way ? Or is there something wrong doing so ?


    EV adjustment is just a correction factor applied to the metering
    system, to tell the camera that this particular subject needs more or
    less light than the (simple minded) metering system thinks it does.
    For example, if you're shooting in snow, the meter is likely to read the
    white snow as mid-grey, so you need +2.5 exposure compensation to make
    the snow white.

    So, if you're shooting in shutter priority auto mode (fixed shutter
    speed, variable aperture) and you set the EV compensation to +2, the
    aperture will open 2 more stops - if it has 2 more stops of range
    available. If you're already wide open, nothing will change. You can't
    "gain more light", you just get a wider aperture set automatically.

    >If I am in P mode, and adjust EV, then it does so by
    >increasing shutter time. And in T-mode it adjusts the
    >Aperture. So it is my guess, that it will not work.


    In P mode, it may adjust either shutter or aperture or both. If it's
    adjusting shutter time only, the aperture may already be wide open.

    >Can I extract more light from the 12-bit RAW images ?
    >I know some of the extra bits are used for highlight,
    >since you can save some overexposure.


    You can produce a lighter final image. This isn't the same as
    "extracting more light"; it's just brightening the image that you
    captured with insufficient light. It may give you a usable image in
    circumstances where you otherwise wouldn't get anything.

    Dave
     
    Dave Martindale, Dec 21, 2003
    #4
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Sammie Garvin \(Mobile\)

    Low-light/Night Photography

    Sammie Garvin \(Mobile\), Aug 9, 2003, in forum: Digital Photography
    Replies:
    14
    Views:
    848
    pjruiz(nospaam)
    Jan 12, 2005
  2. terry
    Replies:
    0
    Views:
    420
    terry
    Oct 8, 2003
  3. Ted
    Replies:
    0
    Views:
    704
  4. Vance

    The non-night night shot

    Vance, Oct 12, 2010, in forum: Digital Photography
    Replies:
    3
    Views:
    423
    Robert Coe
    Oct 13, 2010
  5. golemnagesh

    Adjustment Images using ImageItem in J2ME

    golemnagesh, Dec 14, 2010, in forum: Software
    Replies:
    1
    Views:
    1,291
    golemnagesh
    Dec 15, 2010
Loading...

Share This Page