When I record or take photos I get these really weird vertical lines going down my image in the shadows. How to I fix this? I don't have it on a high ISO.
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Jonah Tieman
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It would be useful to share the EXIF data (at least Aperture/Speed/ISO) – xenoid Apr 26 '21 at 22:16
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A thread from a few years ago attributes this behavior to grid noise. – emmit Apr 27 '21 at 00:11
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but it doesn't answer how to fix it. – Jonah Tieman Apr 27 '21 at 01:18
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@JonahTieman The lead sentence of the last paragraph of the accepted answer: "One way to avoid read noise is to shoot the scene with a brighter setting (more light, longer shutter time, etc.) and then reduce the brightness in post processing." – Michael C Apr 27 '21 at 01:21
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It's read noise. The same amount of read noise is present in the entire photo, but in the brighter areas there's enough light to overwhelm it and you can't see it.
How to I fix this?
Shoot in brighter light and/or expose appropriately for the shadows.
If there's too wide a range between the brightest areas of the scene and the darkest so that the highlights would be blown before the shadows are exposed well enough, then as the photographer you need to add light to the darker areas.
I don't have it on a high ISO.
Even when shooting at low ISO, when you underexpose the shadows you'll get more noise in the shadows. High ISO isn't really what causes increased noise. The lower amount of light we usually allow into the camera when using higher ISO is what causes noise. If you limit the light to the same level at ISO 100 that you would use to properly expose for, say ISO 3200, and then try to boost those almost black shadows by five stops in post, you'll see the same thing as using ISO 3200 with the same exposure time (Tv) and aperture (Av) when shooting.
For more, please see:
Should higher ISOs really be preferred (all other things being equal)?
Michael C
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so basically shoot in a brighter setting and use post production to fix it. – Jonah Tieman Apr 27 '21 at 16:59
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@JonahTieman This kind of noise can be more noticeable with Canon cameras if optional NR is disabled because they don't do as much (forced) on-die analog noise reduction as some other manufacturers tend to do. Like many design decisions, there are advantages and disadvantages to such a choice. ("Raw" images look cleaner with sensors that do NR before ADC, but such cameras also tend to be "star eaters". Pay your money and make your choice.) If you have no NR enabled in-camera, you definitely need to post-process it. Using default NR in camera usually works well enough, though. – Michael C Apr 28 '21 at 01:51