K-3 high-ISO test shots — FANTASTIC!

Started Mar 7, 2014 | Discussions thread
MightyMike Forum Pro • Posts: 38,599
Re: Thoughts.

lock wrote:

Impressive. How much noise reduction did you gain from the downsampling ?


the effective noise (ISO) reduces by the square root of the downsize ratio

you take a 6016x4000 image and reduce it to 3008x2000 and that should give you 1/2 a stop, reduce to 1504x1000 and you've got 1 stop... the reason its the square root is that takes into account the randomness of noise, if it were perfectly uniform then the reduction would be equal to the ratio, but if it were uniform we'd also have perfect NR algorithms.

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Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'

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