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New Contributor
Posts: 3
Registered: ‎02-20-2013

Why does higher ISO produce grain?

I am trying to understand how ISO works. My primary research tells me that in olden days, the granules of photosensitive material used on a film type would be finer for films rated at lower ISO. So what is the equivalent in the digital era? What is it exactly that generates the noise? 

Respected Contributor
Posts: 1,861
Registered: ‎12-02-2012

Re: Why does higher ISO produce grain?

Hi, VTORD.

 

Here is a pretty good graphic explanation. 

 

See http://www.cambridgeincolour.com/tutorials/image-noise.htm 

 

and http://www.cambridgeincolour.com/tutorials/image-noise-2.htm

 

Boosting ISO is kind of like cranking up a set of speakers.  You can make the music louder, but the sound quality is reduced because the distortion increases faster than the good signal does.

 

As you boost ISO you don't just add noise, but you lose detail in the image too.

 

Does that help at all?

 

 

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
New Contributor
Posts: 3
Registered: ‎02-20-2013

Re: Why does higher ISO produce grain?

thnx scottyp!

i think i understand it better now. stii learning thoughSmiley Happy

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Respected Contributor
Posts: 1,861
Registered: ‎12-02-2012

Re: Why does higher ISO produce grain?

Everybody's still learning, or if not they are doing something wrong... Smiley Happy

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
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