Help with aperature adjustment

Discussion in 'Beginner Questions' started by john_mcalister, Oct 21, 2015.

  1. I need help with an aperture adjustment in order to remove the graininess of my ISO level. It's a Canon D30 camera.
     
  2. Your picture does not come through. And do you mean Aperture as in the abandoned Apple program or as in lens opening? Posting a picture and/or EXIF info may help too.
     
  3. William Michael

    William Michael Moderator Staff Member

    In addition to answering Jos' questions, please confirm you have a Canon D30 Camera? That is a very old model camera. Do you mean a Canon EOS 30D Camera? The earlier model camera does exhibit more noise even at modest ISO, than the EOS 30D, so confirming the model of camera will be relevant to gaining appropriate and targeted advice regarding the Post Production of the image files.
    *
    If you are asking about how to adjust the Lens's Aperture, then that will firstly depend what CAMERA Mode you are using.
    The CAMERA Mode is selected by turning the MODE DIAL which is located on the top left hand side of the camera as you hold the ca,era with the lens pointed away from you. (The MODE DIAL is located in the same place for both the EOS D30 and EOS 30D models). So you also need to let us know how that MODE DIAL is set if you are asking about setting the Len's Aperture.
    WW
     
  4. Greetings, John
    If you are asking how open or close need to be your aperture to eliminate noise..., you need to OPEN in order to allow more light to get into the sensor and adjust your ISO to a lower number. In older cameras, and also new models, as high your ISO, more evident become your noise... so, open diaphragm to be able to reduce ISO, then you could reduce noise.

    Best regards
     
  5. Hi,
    The best approach to reduce noise is always to use as large an exposure value as you can for the scene you are photographing. And the lesser light that is available in the scene, the larger exposure value you will need.

    Exposure value is a value describing how much of the available light will hit the sensor when the picture is taken. Technically, the exposure value is decided by two camera settings, the f-number (=aperture) and the exposure time. The smaller the f-number you use (=the larger aperture opening you use), the more light hits the sensor. And the longer exposure time you use, the more light hits the sensor. And more light means larger exposure value. At the same time, when more light hits the sensor you can crank down the ISO (which in turn makes very many people thinks it is high ISO that generates noise when it technically is (mostly) due to too little light hitting the sensor during the exposure).

    So if you want to optimize for lowest possible noise, you should use as small f-number as you can and as long exposure time as you can. How small f-number and how long exposure time to use in a given scene will be a decision to be made by you based on the actual scene and how you want the image to be. Things like movement in the scene, whether you want these movements frozen or visible, how trained you are with keeping a camera still during exposure, whether you have a tripod available, wanted depth of field etc. will be the deciding factors. Available light in the scene will also be a factor since to much light reaching the sensor will burn out the brightest parts of the scene. So don't crank up the exposure value too much then. ;-)

    This may look complicated to you, but is pretty simple as you focus on it when taking pictures and gain experience.
    There is a description of exposure value on Wikipedia with a table of exposure values (EV) for different combinations of f-stops and exposure times, but don't go to technical about this: https://en.wikipedia.org/wiki/Exposure_value
     

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