Timeline for Does Manual iso = low noise?
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| Sep 13, 2021 at 16:21 | comment | added | Szabolcs | @PeterBadida I thought it would have taken too much space to go into the explanation. This is why I just put a footnote with a link to the Wikipedia page for shot noise. The idea is that light is not flowing in continuously as water would, but in discrete units (photons), as grains of sand would. If you are pouring sand at the average rate of 3 grains per second, that does not mean that every 1-second long interval will have exactly 3 grains. Some will have none, some 1, 2, 3, 4, 5, 6, etc. While the average is 3, there is a lot of variation. This variation is the noise. | |
| Sep 13, 2021 at 16:17 | history | edited | Szabolcs | CC BY-SA 4.0 |
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| Sep 13, 2021 at 15:55 | comment | added | Peter Badida | "Noise is present directly in the light." I think this needs better explanation. From this one it looks like it's a part of the light as in the particles that reach the sensor which I doubt is the case. Rather particles in the environment (in & out of the lens) coliding with them, sensor not being able to capture every photon, the rest of the electronics corrupting the data, etc. Feel free to correct me or elaborate more. +1 though | |
| Sep 10, 2021 at 18:01 | comment | added | supercat | @IMSoP: A simple way of thinking about ISO is that it increases the amount by which each photon detected in a pixel will boost the brightness thereof. If one is doing X-ray photography of a live subject and needs to minimize the number of photons to which the subject is exposed, and one wants the plate to be 10% exposed when 1,000 photons hit each square centimeter, then each square centimeter of a 10%-exposed plate will have about 1,000 small dark spots in it. If one pushed the developing so that 1,000 photons/cm2 would yield 50% exposure, there would be 1,000 bigger dots. | |
| Sep 10, 2021 at 13:53 | history | edited | Szabolcs | CC BY-SA 4.0 |
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| Sep 10, 2021 at 12:00 | comment | added | IMSoP | Since you're getting into the fundamentals here, it would be interesting to add an explanation of what varying the ISO actually does do. My understanding is that it increases the gain of the sensor - effectively, measuring smaller differences in light levels; and that's why it is more susceptible to noise - the noise which was already present is amplified by the increased gain. | |
| Sep 9, 2021 at 14:25 | history | edited | Szabolcs | CC BY-SA 4.0 |
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| Sep 9, 2021 at 14:01 | history | answered | Szabolcs | CC BY-SA 4.0 |