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02-28-2021, 01:10 PM   #1
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Sensor noise on K3?

Hello everybody,

I have recently noticed that using my K3 I get a lot of noise on 100% crop. Would like to check with you if this is just me or is it normal for this camera to act like this? Haven't noticed before, but maybe I just haven't played with crop as frequently. These are few snapshots I took from 100% crop. ISO is only 100, no digital post-production was made. I understand there might be some digital noise, but isn't it this a bit too much for a 100% crop on K-3 ii? Would appreciate your insights.

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02-28-2021, 02:02 PM - 1 Like   #2
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It looks normal to me. A modest amount of smooth noise evenly distributed. One won't notice it at a normal magnification.
02-28-2021, 02:40 PM - 1 Like   #3
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QuoteOriginally posted by Kiparisas Quote
I understand there might be some digital noise, but isn't it this a bit too much for a 100% crop on K-3 ii? Would appreciate your insights.

My understanding is that digital noise is fairly common in blue skies and possibly in other areas of uniform colour. It might be due to the RGB Bayer filter configuration, in which only 25% of the photosites are filtered to blue. The demosaicing approach also affects the quality of the blue areas.

Coincidentally, I was just processing a couple of my images that have significant areas of bright blue sky. At ISO values of 100 and 200, I noticed speckles similar to your images. A modest, light-handed noise-reduction approach cleaned it up nicely.

The RAW developer app that I use -- RawTherapee -- has a one-touch setting to 'reduce artifacts in blue sky', which works okay but can introduce artifacts elsewhere. I use a combination of noise reduction and contrast control to manage low-ISO noise.

I shoot with a K-3 II, and have also noticed some 'blue-sky speckles' in my earlier K-5 II images, although to a lesser degree.

- Craig
02-28-2021, 04:18 PM   #4
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Thank you for clearing this up! I have always wondered why sometimes the noise is not too evident, whereas at times it's very noticible, as in these cases!

03-01-2021, 10:46 AM   #5
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Looks normal to me. Those areas are kind of dark so that may be part of it too, so maybe throw some more exposure at the image. I get some noise like that in darker uniform sections of images as well and adding a bit more exposure helps out with clearing it up but avoid clipping highlights, or even getting things piled up near the edge.

The noise removal features in RawTherapee can do a great job of cleaning that up if it really bugs you or you need a real clean image. Also playing with the wavelet contrast and contrast by level sliders can also do wonders for cleaning it up in RawTherapee.
04-18-2021, 08:06 AM - 1 Like   #6
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That kind of noise is fairly easy to deal with in photo editors, and not unusual in flat areas of color. It shouldn't be a concern on prints or when viewing photos at less than 100%.
04-19-2021, 02:54 AM   #7
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Thank you guys for your insights. I have noticed such noise is more evident when photos are taken in the low light conditions.

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