ISO related question

Discussion in 'Beyond the Basics' started by Grujanidas, Apr 15, 2017.

  1. Grujanidas

    Grujanidas TPF Noob!

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    I hope this question is not stupid enough, considering myself as
    a beginer. So, for example, If I increase ISO, with let's say aperture priority mode on, not even important, I noticed my image is more sharper than captured image with lower ISO. Is this true or not generally speaking? I have noticed that people always trying to keep ISO as low as possible, but latter on in post lifting the shadows introduce grain and maybe even more noise than probably with increased ISO right there at shoting location.
    Does something of this makes any sense to you?

    Послато са SM-G903F уз помоћ Тапатока


     
  2. astroNikon

    astroNikon 'ya all Bananas I tell 'ya Supporting Member

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    If you are in Aperture Priority mode you are allowing the camera to make changes as needed for an appropriate Automatic Exposure setting.

    In Aperture Priority mode you are controlling the specific Aperture setting and setting it to a fixed setting.
    If you increase the ISO, and if the Shutter Speed stayed the same, then your image would be over exposed. But being in an "auto" mode the camera is going to change and Increase the Shutter Speed to compensate.

    If you have an example of an image that is done at one setting then the other we'd be able to show you why as long as the EXIF data is included.

    But basically, at a faster shutter speed you are stopping motion better. Even if you are taking a picture of someone standing there an image at 1/60 Shutter Speed could show the person moving ever so slightly and thus the detail/IQ of the image isn't as good as 1/125. A 1/125 Shutter Speed would stop any slight motion much better and provide a much more finely detailed image.

    this site review those different modes ==> Camera Exposure: Aperture, ISO & Shutter Speed

    => Using Camera Shutter Speed Creatively


    What is important when you are taking a photo, is selecting the appropriate Shutter Speed for the type of image that you want. If you want to stop motion the speed will be different for someone standing there (say 1/125), versus a car driving down the street (say 1/800).
    You can't use a slow Shutter for something moving faster.

    Aperture is the Depth of Field that you'll get for the depth of the object being in focus (or out of focus).

    So you'll always want to select the appropriate Shutter Speed, and the Appropriate Aperture for what image you are taking a photo of. The ISO allows you to then balance out that Exposure. But sometimes you'll have to adjust one setting to compensate not being able to get a proper exposure such as a slower shutter speed which may induce some object movement.

    Depending what you are taking a photo of, Shutter Priority may be a better option, or even Manual Exposure where you can set the Shutter and Aperture and then set the ISO. Also Program Mode may be a better option. Depending what you are doing you'll have to use the best option.
     
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  3. Derrel

    Derrel Mr. Rain Cloud

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  4. fmw

    fmw No longer a newbie, moving up!

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    Yes. Raising ISO in AP mode also increases the shutter speed and, in your case, it raised it enough to avoid motion blur. If you put the camera on a sturdy tripod, you are likely to get a better image with a lower ISO.
     
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  5. dennybeall

    dennybeall No longer a newbie, moving up!

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    As you can see from your question it's all about relationships. Shutter speed stops motion, or not, but you have to adjust the f-stop and the ISO to capture enough light for that photo at that speed. The f-stop effects depth of field but you need speed and ISO to allow the correct amount of light., etc., etc..
    Every situation is different. If anyone tells you to ALWAYS use a particular set of settings, it's probably not right.
     

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