{"id":47743,"date":"2023-07-21T10:33:49","date_gmt":"2023-07-21T10:33:49","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=120577"},"modified":"2023-07-21T12:32:33","modified_gmt":"2023-07-21T12:32:33","slug":"what-is-iso-in-photography-a-quick-guide","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/what-is-iso-in-photography-a-quick-guide\/","title":{"rendered":"What is ISO in photography? A quick guide"},"content":{"rendered":"

What is a camera\u2019s ISO setting for, and how do you use it? <\/p>

By Pete Lawrence\n \t\t<\/p>

2023-07-21 10:33:49<\/p>

\n\n

In photography, an ISO setting on a camera is an indication of its relative sensitivity to light: ISO 200 indicating twice the sensitivity of ISO 100 and so on.<\/p>\n

Whereas the ISO for a roll of film is fixed, a digital camera allows the ISO value to be varied, apparently changing the camera\u2019s sensitivity to light.<\/p>\n

We say \u201capparently\u201d because nothing actually happens to the sensor itself \u2013 its sensitivity remains the same whatever ISO value is selected.<\/p>\n

For more advice, read our guides on how to use a DSLR camera<\/a> and DSLR astrophotography<\/a>.<\/strong><\/em><\/p>\n

\""camera\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>\n

Using and changing a camera\u2019s ISO setting<\/strong><\/h2>\n

What does change with ISO is the amplification or gain of the camera.<\/p>\n

As data is read off the chip it is electronically multiplied by a factor used to simulate the ISO change.<\/p>\n

The downside of using this technique is that the signal-to-noise ratio (SNR) is lowered with amplification, so noise becomes more obvious at higher ISO values.<\/p>\n

This can be somewhat offset by using image stacking<\/a> techniques.<\/p>\n

In addition, the dynamic range of a high ISO image will also be less than that taken on a low ISO setting. Lower ISO gives you better tonal quality.<\/p>\n

\""A\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
A DSLR settings screen will include: 1) ISO; 2) Aperture\/f-stop number; 3) Exposure; and 4) White balance (here on auto, \u2018AWB\u2019)<\/span><\/figcaption><\/div>\n

Think of it this way<\/strong><\/h2>\n

The three main variables in taking a photograph are:<\/p>\n

  • Shutter speed<\/li>\n
  • Aperture<\/li>\n
  • Film\/sensor sensitivity.<\/li>\n<\/ul>

    Imagine a film frame or CCD as a bucket to be filled with water (light).\u00a0In this analogy:<\/p>\n

    • Aperture<\/strong> is represented by the diameter of a hose used to fill the bucket<\/li>\n
    • Shutter speed<\/strong> is the time the hose is running<\/li>\n
    • ISO<\/strong> is the water pressure<\/li>\n<\/ul>

      Double the pressure and the bucket will fill in half the time.<\/p> <\/body><\/html>\n

      ","protected":false},"excerpt":{"rendered":"

      What is a camera\u2019s ISO setting for, and how do you use it? <\/p>\n","protected":false},"author":24,"featured_media":47744,"template":"","categories":[34],"acf":{"readingTimeMinutes":"2"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide.jpg",1200,800,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide.jpg",1200,800,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/what-is-iso-in-photography-a-quick-guide.jpg",1200,800,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"What is a camera\u2019s ISO setting for, and how do you use it?","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/47743"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/47744"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=47743"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=47743"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}