Effect of ISO on Digital Noise
Effect of ISO on Digital Noise
| 1. | Making the test of digital noise |
| 2. | Results of the test |
| 3. | Conclusion |
Higher value of ISO increases the digital noise. What is the highest acceptable value? This test depends most on the device used. What you read in the conclusion will no longer be valid after a few years. It is thus important to know how you can test your digital camera. The test was done the same way as in Making the test of white balance setting. The only difference was automatic white balance and manual ISO setting. The parameters were then obtained by:
exiftool -FileName -ISO -Aperture -ShutterSpeed -FileOrder FileName -ext nef . |
This time the preview in the full resolution (JpgFromRaw) was used and the same detail was always extracted by ImageMagick:
for a in _dsc*
do x=${a%.*}.png
convert $a -gravity West -crop 640x424+250+400 +repage ${x/_dsc/detail}
done |
The table below shows the details for increasing ISO and finally the whole images (Preview Image) for the lowes and highest ISO.
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| ISO: 64, Aperture: 2.8, Shutter Speed: 1/5 |
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| ISO: 80, Aperture: 2.8, Shutter Speed: 1/6 |
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| ISO: 100, Aperture: 2.8, Shutter Speed: 1/8 |
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| ISO: 125, Aperture: 2.8, Shutter Speed: 1/10 |
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| ISO: 160, Aperture: 2.8, Shutter Speed: 1/13 |
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| ISO: 200, Aperture: 2.8, Shutter Speed: 1/15 |
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| ISO: 250, Aperture: 2.8, Shutter Speed: 1/20 |
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| ISO: 320, Aperture: 2.8, Shutter Speed: 1/25 |
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| ISO: 400, Aperture: 2.8, Shutter Speed: 1/30 |
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| ISO: 500, Aperture: 3.2, Shutter Speed: 1/40 |
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| ISO: 640, Aperture: 3.2, Shutter Speed: 1/40 |
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| ISO: 800, Aperture: 3.5, Shutter Speed: 1/50 |
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| ISO: 1000, Aperture: 3.5, Shutter Speed: 1/50 |
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| ISO: 1250, Aperture: 4.0, Shutter Speed: 1/60 |
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| ISO: 1600, Aperture: 4.0, Shutter Speed: 1/60 |
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| ISO: 2000, Aperture: 4.0, Shutter Speed: 1/60 |
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| ISO: 2500, Aperture: 4.5, Shutter Speed: 1/80 |
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| ISO: 3200, Aperture: 4.5, Shutter Speed: 1/80 |
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| ISO: 4000, Aperture: 5.0, Shutter Speed: 1/100 |
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| ISO: 5000, Aperture: 5.6, Shutter Speed: 1/125 |
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| ISO: 6400, Aperture: 5.6, Shutter Speed: 1/125 |
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| ISO: 8000, Aperture: 6.3, Shutter Speed: 1/160 |
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| ISO: 10000, Aperture: 6.3, Shutter Speed: 1/160 |
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| ISO: 12800, Aperture: 7.1, Shutter Speed: 1/200 |
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| ISO: 16000, Aperture: 7.1, Shutter Speed: 1/200 |
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| ISO: 20000, Aperture: 8.0, Shutter Speed: 1/250 |
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| ISO: 25600, Aperture: 8.0, Shutter Speed: 1/250 |
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| ISO: 64, Aperture: 2.8, Shutter Speed: 1/5 |
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| ISO: 25600, Aperture: 8.0, Shutter Speed: 1/250 |
The results show that the limit value for Nikon D850 is somewhere around ISO 4000. If the image is prepared for web only, then the noise is not apparent even at the highest value. The test however showed that autofocusing mechanism has problems for high ISO if there is enough light.
Remember that higher digital noise is more acceptable than unwanted motion unsharpness.