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Thread: can someone help with iso aperture and shutter-speed

  1. #1
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    dylan young

    can someone help with iso aperture and shutter-speed

    i have read from many pages about iso aperture and shutter speed but i dont understand still it. i am new to photography i am 16 still in high school but i like to take pictures,and i would like to expand my skills. so any help with learning on howto make better pictures and any tips aswell.

  2. #2

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    Re: can someone help with iso aperture and shutter-speed

    Have you visited the Tutorials section of this website? That is a good place to start.

  3. #3

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    Re: can someone help with iso aperture and shutter-speed

    Quote Originally Posted by dylany View Post
    i have read from many pages about iso aperture and shutter speed but i dont understand still it. i am new to photography i am 16 still in high school but i like to take pictures,and i would like to expand my skills. so any help with learning on howto make better pictures and any tips aswell.
    Google for "exposure triangle". There is a lot of youtube movies or websites with animation. Once you kmow the relation between them, you might have more specific questions.

    George

  4. #4
    inkista's Avatar
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    Re: can someone help with iso aperture and shutter-speed

    One really good book to help you figure it out is Bryan Peterson's Understanding Exposure. You can probably find an older edition in the public library if you want to read it before buying it.

    Basically, iso is the sensitivity of your medium to light. The higher the number, the faster you can grab more light, but the more noise or grain you'll see in the final image.

    Aperture is how big the hole in the lens is to let in light. f-numbers are a little tricky to understand, but they're ratios or fractions, so the smaller the number, the bigger the hole is (e.g., f/4 is bigger than f/8) and the more light you get, but the less stuff you get in focus at the same time (depth of field).

    Shutter speed is how long you leave the hole open to let the light in. The longer the speed, the more light you get, but the more possibility you end up with blur in the image--either from camera shake or from subject movement.

    All three of these settings can be measured in "stops" (aka EV=exposure value), and you can swap stops among the settings to balance out all the tradeoffs for what you want. So, for example, if you have your settings where the exposure is good, but you're worried about motion blur, and you want to double your shutter speed (-1 stop), then you can keep the same exposure by adding a stop on the iso or the aperture (e.g., going from iso 200->400, or from f/8 to f/5.6).

    If you're in M mode for the first time, the main tool for you is the meter in the viewfinder. You may be more used to thinking of it as your exposure compensation scale if you've been using the automated modes, because the camera's auto-exposure system always sets the needle to 0. In M mode, however, it's your meter, and tells you how much light you're getting with your current settings, and it's marked off in stops/EV. And you can just monkey with any one of the three settings until the needle moves to where you want it to sit, so the camera can do all the one stop-of-this-that-or-the-other calculations for you.

  5. #5
    rpcrowe's Avatar
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    Re: can someone help with iso aperture and shutter-speed

    Welcome to CiC... Here is a quickie explanation of what we generally call the exposure triangle.

    Aperture: Which is the hole that allows the light to come through the lens. The larger the aperture the more light allowed through the lens for any given time. The size of the aperture is usually calculated in f/stops. Since we are talking reciprocals here, a larger f/stop number indicates a smaller hole letting in less light. The smaller number indicates a larger hole, letting in more light. Just as the fraction 1/2 is larger than the fraction 1/4, the aperture f/2 is larger than the aperture f/4. Just how much larger will be explained in the tutorials.

    Shutter-speed: Is the amount of time that the shutter allows light to hit the sensor. Naturally, the longer the shutter allows the light to hit the sensor the more light hits that sensor. Shutter speed is usually defined in fractions of a second 1/30, 1/125 and so on. Longer exposures will be designated in seconds 1-second, 2-seconds, 4-seconds, etc. Obviously, 1/30 second is twice as long as 1/60 second. How the shutter speed impacts the image besides being a part of the total exposure is covered in the tutorials.

    ISO: Is the sensitivity of the sensor. The more sensitive, higher ISO, the less light is needed to record an image. Lower ISO values are usually chosen when the light is brighter and higher ISO values are chosen when the light is dimmer. However, there are often other reasons to increase or decrease ISO values. This will be covered in the tutorials...

    Think of it this way:

    If I have a bucket, which when filled with water from a garden hose is the correct exposure.

    Consider the f/stop or aperture as the size or diameter of the hose. The larger hose at the same pressure will fill the bucket quicker.

    Consider the ISO as the water pressure. The higher the pressure, the quicker the bucket will fill.

    Consider the shutter speed as the time it takes to fill the bucket.

    I think that perhaps, you can now see the interrelationship of f/stop, shutter speed and ISO. Change any one of these parameters and either or both of the other two parameters will need to be changed.

    I recommend that you read the Tutorials on this site to see how each of the three parameters will change the image while still retaining the same total exposure if one or both of the other two parameters are changed...

    You have basically five ways to select your exposure:

    1. Full automatic - you have no choice in the matter of ISO, aperture or shutter speed. The camera selects everything for you.

    2. Programmed exposure - the camera will select the exposure for you but you have control over how you want the exposure parameters selected.

    3. Aperture priority - you select the aperture and ISO and the camera will select the appropriate shutter speed.

    4. Shutter priority - you select the ISO and shutter speed and the camera will select the proper aperture.

    5. Manual exposure - you select ISO, shutter speed and aperture.

    When to select each of the above is another matter and is covered in the tutorials.

    I would not recommend using Full Automatic because it takes away all control from the photographer.

    I use any of the modes 2-5 determined by which I believe is the best choice for the situation in which I am shooting...

    However, I suggest that a beginning photographer get some experience before selecting full manual exposure.
    Last edited by rpcrowe; 23rd September 2015 at 05:13 PM.

  6. #6
    Moderator Dave Humphries's Avatar
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    Re: can someone help with iso aperture and shutter-speed

    Hi Dylan,

    If you prefer a visual learning experience, this Adorama example is quite good.
    It runs just under 7 minutes.



    As you are new here, may I offer you a warm welcome to the CiC forums from me.

    Could you do me a favour please?
    Could you click Settings (right at the top),
    then Edit Profile (on left)
    and put your first name in the Real Name field (Dylan I guess)
    and where you are (roughly) in the Location field,
    then click the Save Changes button below and to right,
    this helps everyone give you more personal and relevant answers - thanks in advance.

    Hope that helps, Dave

  7. #7
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    Re: can someone help with iso aperture and shutter-speed

    You can learn and practise as much as you need for free here -

    http://camerasim.com/apps/original-camerasim/web/

    Cheers.
    Philip

  8. #8
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    Re: can someone help with iso aperture and shutter-speed

    Quote Originally Posted by MrB View Post
    You can learn and practise as much as you need for free here -

    http://camerasim.com/apps/original-camerasim/web/

    Cheers.
    Philip
    This app is amazing. It lets you change the settings and see how the picture should turn out!

    Thanks
    Javed

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