7D Mark II noise at low iso

[thegios]

This is a 3:1 crop taken with a 7D Mark II with a Canon 17-55 f2.8 lens at 17mm f11 iso 100 1/200 sec: is it normal such a noise on the sky?

[thegios]

TCampbel: that's exactly what I do 😉

ebiggs1: I always use neutral picture style with all values set to zero, to avoid LR from interpreting wrongly any in camera picture style while importing

[ebiggs1]

"... to avoid LR from interpreting wrongly any in camera picture style while importing"

OK, I think you have a good understanding how LR works.

[Peter]

Photon shot noise:

"An important characteristic of fluctuations obeying Poisson statistics is that their standard deviation -- the typical fluctuation away from the average in the typical count -- is equal to the square root of the average count itself. That is, if 10000 photons are collected on average, the typical fluctuation away from this average number of photons will be about 100 -- the counts will typically range from about 9900 to 10100. If instead on average 100 photons are collected, the variation from count to count will be +/- 10. Thus, as the signal grows, the photon shot noise also grows, but more slowly; and the signal-to-noise ratio increases as the square root of the number of photons collected. The higher the illumination, the less apparent the shot noise; the lower the illumination, the more apparent it is."

Below is the raw histogram from your raw file. You could have collected a lot more photons before clipping the highlights.

[thegios]

Translated: pic is underexposed and therefore noise is higher, I could have increased exposition (as I had plenty of room) to minimize the noise?

Correct?

[Peter]

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@thegios wrote:
Translated: pic is underexposed and therefore noise is higher, I could have increased exposition (as I had plenty of room) to minimize the noise?

Correct?

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Correct. Collect more light. To check the raw histogram I have used RawTherapee.

[ebiggs1]

Peter excellent conclusion and explanation.