fiddling with exposures

Discussion in 'Photography Beginners' Forum' started by Jono, Feb 4, 2007.

  1. Jono

    Jono TPF Noob!

    Feb 3, 2007
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    just realised my little Easyshare had an exposure adjustment function from -2.0 to +2.0 (i'm new to this so bear with me!) so had a fiddle & took some shots of the fire in our lounge. Some look better than others and some are just bad. I cant remember which was what exposure was used on what picture. Can someone explain to me what the exposure actually does in laymans terms & how I can use this to my advantage.Thanks in advance.



    3::(in black & white)[​IMG]




  2. firemedic0135

    firemedic0135 TPF Noob!

    Jan 16, 2007
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    East Texas
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    You should go in and edit your url paste and seperate each image on a different line instead of all together to make this a little easier to read to start off.:thumbup: Exposure as best I know is a combination of shutter speed,aperature,and ISO .when all these come together you have an exposure.Kinda like time+volume+sensitivity=exposure.
    if you want something over exposed you could increase the time the shutter is open,or increase the size of the aperture(volume),or increase the sensitivity of the sensor/film.reverse any one or more of these to underexpose.
    Someone else on here may be able to epxplain it better than me though.:thumbup:
  3. LaFoto

    LaFoto Just Corinna in real life Staff Member Supporting Member

    Feb 1, 2004
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    Lower Saxony, Germany
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    Somehow you must expose your film (or sensor, for that matter) to light. Else it would always be in the total dark and nothing would happen.

    And you expose it to light through the lens of your camera.
    In that lens, something will open for either a fraction of a second or - in the case of long exposures - a whole second or even several seconds, half a minute, for as long as you like (which will not be possible with your Easyshare), etc.

    So you have the time value of exposing your film/sensor to light.

    Then you can open the little hole (opening = aperture) more or less.
    Just like the pupil in our eyes gets wide in darkness to adapt to what little light there still is that reaches the receptors at the back or our eyes, or tiny in bright sunlight, so our retina does not get too much light for us to handle, you can open up that little hole in your lens or leave it small. So if you want light to fall onto your film/sensor through a small opening only, you chose a small aperture. Watch out: SMALL aperture equals a high number! So f16 sounds big, but means small hole. f2.8 sounds small but is a wide open aperture!

    Choice of aperture does not only have influence on the amount of light that falls onto your film/lens. It sure has some, but that can be counteracted by choosing a shorter exposure time to get the RIGHT exposure. It also has quite some influence on the DOF (depth of field) you get, i.e that area within your photo where there is the focus, where everything is sharp. With a wide open aperture, only a small area will be sharp, everything before that or behind will be blurred. A small aperture, on the contrary, will give you a much deeper DOF and much larger parts within your photo will be sharp and in focus, which can go from foreground to eternity even.

    Now ISO is something that can only this easily be changed in digital photography. For film users they have to make the decision on how sensitive to light their film needs to be before they load it into their camera. If a film user knows he's going on holidays to Spain where there will be bright sunshine at almost all times, a low ISO film will certainly do. If another photographer plans to do a series of photos in a restaurant, with the given light only, i.e. not using a flash or any other additional lights, he will choose a high ISO film, with a higher light sensibility, so what little light there will be will still show on his negatives.

    This can be changed from image to image for the digital camera users these days. Low light ... you go to high ISO and can thus diminish your exposure time, so you can maybe still handhold photos that would otherwise DEFINITELY get blurred through camera shake.

    But one thing needs to be watched: high ISO film has always given grainy negatives/grainy prints. And a high ISO setting in digital photography will produce the digital equivalent to grain: noise.

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