Nikon Z/ Raw Artifacts
I've been noticing what I assumed to be dead pixels from my nikon z raw files, however after using 3 other Z cameras (Z5, Z6ii, Z7) it definitely appears to be a raw converter issue.
Anyone else seeing this? Any fixes?
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Pretty much all cameras have dead/hot pixels: Capture One is supposed to map them out automatically, but it can be hit-and-miss sometimes.
I'm confused though: which camera are you having the problem with?
Your mention of "3 other Z cameras" suggests that you're talking about a different one (but there isn't a "Nikon Z") and it's not clear whether or not they're affected too...
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Are the dead pixels in the same place?
It would be strange if files from all 4 "Z cameras" had dead pixels showing in the exact same place(s).
Are you sure it's a single pixel and not something a little bigger like a dust speck? If you use the same lens with your 4 different bodies it could be a dust speck on the rear element.If there's really many coloured/strange pixels you could try disabling OpenCL hardware acceleration.
It's known to cause issues for some.Otherwise, yes, one or two hot/dead pixels is 'normal'. Most cameras allow you to map hot pixels by taking an exposure with the shutters closed which is then analysed. Capture One can help out with the Noise Reduction tool's 'single pixel' slider. Of course you can also use a very small spot healing brush to fix one photo and then copy to the rest of the set.
Never heard of C1 mapping them out by default. Can't find any documentation on that either.
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Literally all the camera has shown randomly placed "dead" pixels. Usually in the dark areas of the image. Usually brightly colored red or green pixels.
I'll try the openCL thing. Thanks
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Never heard of C1 mapping them out by default. Can't find any documentation on that either.
I never said "by default", but I probably could have used a better word than "automatically" (although once invoked it is technically an automatic - rather than a hands-on, cloning out pixel-by-pixel - process, so...)
Yes, I'm thinking of the "Single Pixel" tool:
The filter will analyze single pixels compared to the surrounding area and correct the errors.
https://support.captureone.com/hc/en-us/articles/360002615758-The-Noise-Reduction-tool
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I'll try the openCL thing. Thanks
Won't help with what you're describing, which - if they are pixel-sized - is definitely "stuck" pixels.
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If we're talking dark, could it be a case of sensor noise? Especially obvious on longer exposure and higher ISO.
The fact you call it 'randomly placed' makes me think it's not hot/stuck (sub)pixels. If this was the case, they'd show up in the same spot on different photo's.
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I've looked at dark areas in some of my Fujifilm pictures at 200% and only found single coloured (blue) pixels in high ISO + longer exposure like 1/6s.
These coloured pixels are emphasized when:
- Raising shadows in the high dynamic range tools
- Using the dehaze tool
Looking at out of camera jpeg as a comparison (or the jpeg preview in a raw) it is obvious my camera by default applies more (high ISO) noise reduction than C1 does at the cost of detail. The SOOC image does not show these blue pixels, but also looks quite soft.
To improve the situation in C1 i found:
- Go light on the dehaze tool or drop it altogether.
- Increase the noise reduction's colour slider from 50 to say 70
Examples below, raised shadows by 10 and used dehaze at 30 to emphasize the issue.
First with default denoise:
then with denoise colour to 70:
Now the question to Bryan: Do you see these stuck pixels in 'normally' lit and exposed pictures or are these high ISO & longer exposure cases? When you spot them, are there several all over the dark area or is it more like 1 or 2 in the whole picture?
Perhaps it's easier if you post a snapshot of the problem or share the raw file.0 -
Thanks everyone. Here's some samples.
First - Original file
Second - Raised 1 stop (just to highlight the issue)
Third - Raising single pixel to 1 in the noise reduction panel seems to completely fix it.
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That does look like there's quite a few of them and this is only a part of the photo. I'd hope they're not actual permanent hot pixels, but rather noise.
They're obviously not dust specks.- Are these present in the exact same spots on different photo's? Yes: hot pixel / No: noise
- Was the above example a case of long exposure? (doesn't look like high ISO to me and C1 defaults single pixel to 30 on high ISO)
The longer the exposure and the hotter the sensor gets the higher the chance of seeing these pixels appear. - Have you done a pixel mapping on the camera yet? Should be an option in the menus, otherwise I found this "Do two back-to-back sensor cleaning cycles from the setup menu. That will run Nikon's hot-pixel remapping logic, which should remove these pixels."
Otherwise good to know you have a simple fix in the single pixel slider.
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Hi,
I seem to have a similar issue. I don't see any hot/dead pixels on the original RAW file. But once I import the file into Capture One, I see a magenta artifact in the same location on all the photos. I use the Nikon Z7 II. I first thought something was wrong with the camera. Then I imported all the images into Lightroom and there were no dead/hot pixels in it. So is this a Capture One problem? Using the Single Pixel slider seems to fix it when zoomed in, but the odd pixel pops up back again when zoomed out of the picture. This is a weird behavior. I would appreciate any help. I am a new C1 user.
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A screenshot often tells more than thousand words..., (but there is a limit of 2MB or so)
One magenta pixel is probably a dead pixel, and LR might handle them automatically where C1 leaves you the choice, I assume.
Here's the thing re. the zoom level:
When you "zoom out", the NR tool won't have any effect. It depends on the zoom level wether or not the NR is applied, the exact zoom level where this switch occurs might (or might not) depend on some factor like monitor resolution, ISO of the image, power of your computer (This is an assumption as I remember that other forum member observed this at another zoom level than I did). The NR switch off is also noticable with high ISO images which have so much color noise that you can see a color shift e.g. to magenta in the lower zoom levels (as reported by someone here in the forum a while ago).
I think C1 does this for performance reasons.
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Thank you for responding! What is perplexing to me is that the RAW file doesn't have those artifacts or the magenta tint that appear after importing into C1. I just think C1 is not handling the NEF files well here. I processed the files using DXO PureRaw 3 and imported the resulting DNG files in C1. I did not notice the magenta tint or any artifacts whatsoever. It only happens with the NEF files. I am attaching a screenshot. On the left is the NEF imported into C1. On the right is the NEF file opened with the default Preview app.
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