Q3 - HighISO stain

[kamilz]

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Hello,

I am new with Q3 and I try to test high ISO (100000) And in camera photo looks great. But if I download to my laptop with LR then I see a stain on the photo. It is problem camera or LR(Adobe)

 

https://ibb.co/HFHNZSp

 

Thank you

Kamil

 

 

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[jaapv]

I see a lot of colour noise - not unexpected with 100.000 ISO and a significant underexposure. You can try to save it with AI noise reduction.  A small LCD will show this a lot less. I would say that you have pushed the camera far beyond its boundaries. 

[kamilz]

I dont think soo that i  push the camera far beyond. I don't understand why there is a strange stain on the photo. I'm not dealing with noise, but why is there a blemish in the photo

[radialMelt]

1 hour ago, jaapv said:

I see a lot of colour noise - not unexpected with 100.000 ISO and a significant underexposure. You can try to save it with AI noise reduction.  A small LCD will show this a lot less. I would say that you have pushed the camera far beyond its boundaries. 

OP is referring to the large circular artifact that takes up nearly the entirety of the right side of the frame. It's quite obvious, and a great question.

[Smogg]

At such ISO values there can be any artifacts. This is an area poorly known to science. It is even possible that aliens of any kind will appear😂

[Qwertynm]

Is the image perhaps cropped in post? Might be the lens profile trying to brighten the sides/corners

[JNK100]

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Unprocessed 100k iso - only to be expected I am afraid.

I go to 6400 iso and use DXO noise reduction which is my max.

[NightPix]

It looks to me like it could be the demosaicing artifact as the algorithm struggles to figure out colors in areas where the signal to noise is so high. Using ISO 100,000 is pushing the limits of the camera and software. You might try looking at the RAW file in different software to see if the artifact repeats.

[jaapv]

4 hours ago, radialMelt said:

OP is referring to the large circular artifact that takes up nearly the entirety of the right side of the frame. It's quite obvious, and a great question.

Possibly with the vignette of the lens underexposing even more, the left side being too dark to make the difference. I guess a couple of stops underexposure as well, making this an ISO 400.000 image... Any camera would do the strangest things.

[coleica]

Is there a window nearby where the stain is located?  I would attempt to remove noise as much as possible via LRC or other noise removing s/w.  See what turns out.  

[Stuart Richardson]

Yeah, I was also thinking that this is mostly a result of the in camera processing that it has to do to correct the distortion and vignetting in the lens, which is not designed to be used without in body corrections. There is also probably a shading correction for color vignetting. At this level of ISO and level of underexposure, you are really pushing your luck, as you are trying to separate the faintest signal from mostly noise. It's possible that if you force the camera to take a new dark frame (possible by setting the camera date forward on some cameras), it might give you a slightly cleaner file, but ultimately I agree with Jaap that with a high resolution camera like this you are really pushing your luck with an underexposed ISO 100,000 file. I am not aware of any camera that looks good at that ISO, not even the A7S series or SL2S. If you give them a decent amount of exposure and don't push the files at all while doing some judicious noise reduction, they can sometimes work, but a lot of cameras have strange artifacts at these ISOs (even lower ISOs). Sometimes you see reddish edges, which can be from very faint light leaking in around the lens mount, but that is probably not the case here since the Q is fixed lens...

If it bothers you you can send the file to Leica and see what the customer service says. They might be able to help, but my guess is that they will say is that such an extreme ISO is not always acceptable.

[Stuart Richardson]

8 hours ago, kamilz said:

Hello,

I am new with Q3 and I try to test high ISO (100000) And in camera photo looks great. But if I download to my laptop with LR then I see a stain on the photo. It is problem camera or LR(Adobe)

 

https://ibb.co/HFHNZSp

 

Thank you

Kamil

 

 

You can also try to have the camera shoot to DNG plus Jpeg, and you will see if the artifact is visible in the camera jpeg. If not, then it is more likely the raw processor. But in this case I think it is a hardware or sensor calibration issue, but one that is hard to prevent in such an extreme condition. This kind of thing is why Leica used to limit the ISO on their cameras much more conservatively than other companies. For example, the original S only went to ISO1250, but even for a CCD it still looked pretty decent at that ISO, at least compared to what cameras of the time looked like at their top ISO.

[thighslapper]

I'd agree it's probably over-compensated vignetting correction ..... as there is a faint similar circular artefact top left as well. 

The algorithms that do this clearly don't expect such extremes of ISO plus underexposure. 

Regularly on this forum in the past (with the M9 in particular) there have been complaints about 'sensor issues' etc. in circumstances of usage that the camera was never designed for. 

[SrMi]

A two to three stops underexposed image at ISO 100,000 is outside the normal working envelope (effective ISO 400,000 to 800,000). You cannot expect usable results at that exposure.

[jaapv]

Maybe the OP is unaware that noise is not directly created by ISO value which is no more than amplifying a low sensor signal, much like the volume on your audio set. The noise, however. is caused by less light hitting the sensor which will make the noise/signal ratio worse. The lower the exposure, the higher the noise-relatively. Then you crank up the ISO = amplification to maximum, underexpose severely for good measure and something like this results.  

[Casey Jefferson]

On 5/28/2024 at 6:49 PM, kamilz said:

Hello,

I am new with Q3 and I try to test high ISO (100000) And in camera photo looks great. But if I download to my laptop with LR then I see a stain on the photo. It is problem camera or LR(Adobe)

 

https://ibb.co/HFHNZSp

 

Thank you

Kamil

 

 

If you shoot with the old M8 or M9 you'll see those very often 😂 Due to very poor (compared to Q3) ISO performance and dynamic range, even at ISO800 and underexposed areas will have a lot of these when being lifted. Means you're setting your self up for unreasonable expectations (ISO100,000 is just insane, I usually hit 6400 at most in the dark on my Q2).

[SAronian]

I lightened the image and the positioning of the discoloration makes no sense. Best way to evaluate would be to shoot additional images under the same conditions and see if the discoloration changes position or shape, or if it is fixed.

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[RBNvRBN photo]

That looks very strange indeed and I my mind cannot be the result of digital processing to reduce vignetting or noise or other lens defects. It is not a perfect circle and it isn't in the center either. Can you see the effect at 50.000 ISO or 25.000 ISO? It almost looks like some defect in the coating of the lens. Are you using a UV or protective filter?

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[kamilz]

22 hours ago, RBNvRBN photo said:

That looks very strange indeed and I my mind cannot be the result of digital processing to reduce vignetting or noise or other lens defects. It is not a perfect circle and it isn't in the center either. Can you see the effect at 50.000 ISO or 25.000 ISO? It almost looks like some defect in the coating of the lens. Are you using a UV or protective filter?

No I don`t use any filter.