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What is a normal noisy/hot pixel behavior for a used Canon 6D?

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#1 zernikepolynomial

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Posted 09 May 2022 - 08:36 PM

I got a used Canon 6D, and all I ever used was a Nikon D5100 but it was not really for astro. I connected the 6D to APT and took some darks. Not really sure if its below average or standard for its age, assuming it could be like 6-10 years old. 

 

 

D M82 0007 ISO800 1s  27C
Album: Test Photos (used Canon 6D)
11 images
0 comments

 



#2 Michael Covington

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Posted 09 May 2022 - 08:52 PM

The Nikon does some hot pixel subtraction in camera, before writing the NEF file, even if long exposure noise reduction is turned off.  The Canon does not.  So they are not directly comparable -- the Canon will look worse because its image is more truly raw.



#3 zernikepolynomial

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Posted 09 May 2022 - 10:07 PM

The Nikon does some hot pixel subtraction in camera, before writing the NEF file, even if long exposure noise reduction is turned off.  The Canon does not.  So they are not directly comparable -- the Canon will look worse because its image is more truly raw.

That is good to know smile.gif . However, I am more interested in how it compares to other canon 6d's. The exposures I took were ISO 800 @ 1s and ISO 800 @ 60s, and I can see hot pixels in both (obviously much more with the 60s); the real question is what is normal for the sensor. The camera is in otherwise great condition, but if its too hot for astro I could easily sell it to someone not doing astro and get another one; I would not really be wasting any time because I am still building this setup. 


Edited by zernikepolynomial, 09 May 2022 - 10:07 PM.


#4 Michael Covington

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Posted 09 May 2022 - 10:28 PM

Right, I hope someone with a Canon 6D pops up and can give a specific comparison.



#5 zernikepolynomial

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Posted 10 May 2022 - 02:01 AM

I added the zoomed in crops of the 60s dark, at 800 ISO. One is the raw file zoomed in, the other is raw and no demosaicing to see any pixel clusters. 

 

demosaicing:

Zoomed 800ISO 60s

 

no demosaicing:

NoDemosaicing Zoomed 800ISO 60s


#6 T~Stew

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Posted 10 May 2022 - 07:57 AM

I'm working a 72hr week this week (plus 1hr drive each way work/home) so not sure if I'll have much time to shoot a comparison for you. I do have some darks I think for my 6D but only at ISO 1600 and 3200, I've never shot lower than that.



#7 zernikepolynomial

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Posted 10 May 2022 - 04:36 PM

I'm working a 72hr week this week (plus 1hr drive each way work/home) so not sure if I'll have much time to shoot a comparison for you. I do have some darks I think for my 6D but only at ISO 1600 and 3200, I've never shot lower than that.

I took some 1600 and 3200 iso shots at 60 and 30 second exposures.

 

EDIT: Might want to set them to large and then open them in new tab

 

EDIT2: I also want to say I left the NR setting at its default standard

 

1600 ISO @ 60s

D M82 0001 ISO1600 60s  NA
 
1600 ISO @ 30s
D M82 0002 ISO1600 30s  NA
 
3200 ISO @ 60s
D M82 0003 ISO3200 60s  NA
 
3200 ISO @ 30s
D M82 0004 ISO3200 30s  NA

Edited by zernikepolynomial, 10 May 2022 - 04:42 PM.


#8 vidrazor

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Posted 11 May 2022 - 12:18 AM

I believe the Canons have a buffer than can handle in-camera noise reduction while shooting so there is no delay in shooting, if so simply set the in-camera noise reduction on. It will create a dark frame on the spot and subtract it from your light frame. You can skip shooting darks as well.


Edited by vidrazor, 11 May 2022 - 12:19 AM.


#9 zernikepolynomial

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Posted 11 May 2022 - 12:38 AM

I believe the Canons have a buffer than can handle in-camera noise reduction while shooting so there is no delay in shooting, if so simply set the in-camera noise reduction on. It will create a dark frame on the spot and subtract it from your light frame. You can skip shooting darks as well.

I plan on just shooting one set of darks, would probably be faster.



#10 vidrazor

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Posted 11 May 2022 - 06:17 AM

I plan on just shooting one set of darks, would probably be faster.

The point is you can shoot as you go along without any time penalty. In other words, you never have to worry about darks at all.



#11 michael8554

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Posted 11 May 2022 - 10:44 AM

To take a dark frame to subtract from the light the camera has to expose for the same duration as the light.

 

So shooting with NR on doubles the time of completing each light.

 

Many Canon users, including myself with a 6D Mk I, don't take Darks, as their temperature changes from light to light.

 

And Canon's do some clever noise reduction in the DIGIC processor before writing.

 

Instead use a master bias as the dark when stacking.


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#12 piaras

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Posted 11 May 2022 - 11:50 AM

Honestly I never did shoot many darks with my 6D. I took lots and lots of lights over the 5 years I had it.
Pierre



#13 T~Stew

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Posted 11 May 2022 - 03:54 PM

To take a dark frame to subtract from the light the camera has to expose for the same duration as the light.

 

So shooting with NR on doubles the time of completing each light.

 

Many Canon users, including myself with a 6D Mk I, don't take Darks, as their temperature changes from light to light.

 

And Canon's do some clever noise reduction in the DIGIC processor before writing.

 

Instead use a master bias as the dark when stacking.

The 6D will shoot up to 3 lights before forcing a dark with LENR, so you only need to loose 25% of your imaging time. Temperature change from light to light is one good reason to use the LENR, so each shot is about as matched to its dark as it could be. But the 6D usually isn't too noisy if you shoot at 1600 ISO at least, though I have not tried really long exposures in really hot temps. Anymore I use ASIair for acquisition so not sure if LENR would even work on the FITS file it acquires, haven't tried. 



#14 zernikepolynomial

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Posted 11 May 2022 - 05:12 PM

The 6D will shoot up to 3 lights before forcing a dark with LENR, so you only need to loose 25% of your imaging time. Temperature change from light to light is one good reason to use the LENR, so each shot is about as matched to its dark as it could be. But the 6D usually isn't too noisy if you shoot at 1600 ISO at least, though I have not tried really long exposures in really hot temps. Anymore I use ASIair for acquisition so not sure if LENR would even work on the FITS file it acquires, haven't tried. 

Did you check out my darks? I got ones at 1600/3200 ISO, for 30s, 60s, and 5 minutes.

 

EDIT: Mine seems pretty noisy for 1600 ISO @ 5 minutes


Edited by zernikepolynomial, 11 May 2022 - 05:34 PM.


#15 asanmax

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Posted 11 May 2022 - 05:43 PM

The 6D has a nice low noise sensor with large pixels. I'd suggest to not overthink the noise presence and just shoot more lights. You can even skip shooting darks if you dither.

Have a look at my experiment here https://www.cloudyni...ssing-software/



#16 zernikepolynomial

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Posted 11 May 2022 - 06:40 PM

The 6D has a nice low noise sensor with large pixels. I'd suggest to not overthink the noise presence and just shoot more lights. You can even skip shooting darks if you dither.

Have a look at my experiment here https://www.cloudyni...ssing-software/

I'm not overthinking. I've been trying to find more sources, because most of them are using image hosting software that has expired, so you cant find decent references anymore. From what I could find, it seems my camera is substantially worse than a normal canon 6d. I found a good reference here that has 1600 ISO, 5 minute exposures with 300x300 pixel crops of different canon unmodified cameras (with NR turned off). http://dslrmodificat...w/6DReview.html

 

Compare that with my 300x300 crop with NR turned off at the same settings:

D M82 0001 ISO1600 300s  27C 2 300x300
 
I'm still waiting for more comparisons, but based on this I am probably just going to resell it to somebody who does not care about the high ISO noise and gamble for another one. Plenty of people just want a full frame camera for normal shooting. I could be totally wrong, and my 6d might be average for its age, and that is why I am asking/searching and being patient. My OTA cant get out of the factory right now, so it could be a month or two.

eightcamerascentercrop.jpg



#17 asanmax

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Posted 11 May 2022 - 06:51 PM

I'm not overthinking. I've been trying to find more sources, because most of them are using image hosting software that has expired, so you cant find decent references anymore. From what I could find, it seems my camera is substantially worse than a normal canon 6d. I found a good reference here that has 1600 ISO, 5 minute exposures with 300x300 pixel crops of different canon unmodified cameras (with NR turned off). http://dslrmodificat...w/6DReview.html

 

Compare that with my 300x300 crop with NR turned off at the same settings:

 
 
I'm still waiting for more comparisons, but based on this I am probably just going to resell it to somebody who does not care about the high ISO noise and gamble for another one. Plenty of people just want a full frame camera for normal shooting. I could be totally wrong, and my 6d might be average for its age, and that is why I am asking/searching and being patient. My OTA cant get out of the factory right now, so it could be a month or two.

eightcamerascentercrop.jpg

Hmm, your previously uploaded crops don't have this level of noise. I have never seen that amount of noise in 6D cameras. Are you sure this crop is not stretched?



#18 zernikepolynomial

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Posted 11 May 2022 - 07:04 PM

Hmm, your previously uploaded crops don't have this level of noise. I have never seen that amount of noise in 6D cameras. Are you sure this crop is not stretched?

 

I followed the exact same procedure as outlined by the referenced site. The other uploaded pictures were not cropped, but just the default processing of large format jpegs directly from the camera.

 

EDIT: Only thing I can think of is the battery, but the temps are also not that different from room temperature as I only did one exposure and not a set. 


Edited by zernikepolynomial, 11 May 2022 - 07:06 PM.


#19 asanmax

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Posted 11 May 2022 - 11:21 PM

Below is a 100% crop of a dark frame taken using a 6D camera that passed our QC today and is on its way to one of our customers.

I don't really see the amount of noise that you had in your cropped image. I wonder if there is something wrong with the camera or the sensor.

 

Edit: all noise reduction options are turned off. The image was taken in tethered mode using APT.

Attached Thumbnails

  • 6D_ISO1600_120sec.JPG

Edited by asanmax, 11 May 2022 - 11:22 PM.


#20 zernikepolynomial

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Posted 12 May 2022 - 01:21 AM

Below is a 100% crop of a dark frame taken using a 6D camera that passed our QC today and is on its way to one of our customers.

I don't really see the amount of noise that you had in your cropped image. I wonder if there is something wrong with the camera or the sensor.

 

Edit: all noise reduction options are turned off. The image was taken in tethered mode using APT.

Its only at long exposure and high iso. So I think its just an abnormally noisy sensor. I guess it will have to go to someone who just wants a full frame camera and is not into astro or long exposure photography. I got it cheaper than it normally goes for used, so getting back my money will be really easy. 



#21 zernikepolynomial

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Posted 12 May 2022 - 06:20 AM

Why am I so unlucky? Everything about the camera is in good condition. The sensor and the optical layers look great. Everything is functioning correctly. Shutter count was pretty good. But the sensor is just way noisier than normal. And because its in great shape, it had to have been this way since the factory, and the seller just had no idea it was that noisy at long exposure and high ISO. What are the odds. If I used the camera for anything else it would be a great full frame camera. But it just happened to be the unlucky astro 6d.


Edited by zernikepolynomial, 12 May 2022 - 06:21 AM.


#22 sharkmelley

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Posted 12 May 2022 - 07:16 AM

I found a good reference here that has 1600 ISO, 5 minute exposures with 300x300 pixel crops of different canon unmodified cameras (with NR turned off). http://dslrmodificat...w/6DReview.html

 

Compare that with my 300x300 crop with NR turned off at the same settings.

Further down on the same Gary Honis page there's a "Lady Liberty" image taken with the 6D.  Again this is a 300sec exposure at ISO 1600 and it shows plenty of noisy pixels.



#23 asanmax

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Posted 12 May 2022 - 09:50 AM

Why am I so unlucky? Everything about the camera is in good condition. The sensor and the optical layers look great. Everything is functioning correctly. Shutter count was pretty good. But the sensor is just way noisier than normal. And because its in great shape, it had to have been this way since the factory, and the seller just had no idea it was that noisy at long exposure and high ISO. What are the odds. If I used the camera for anything else it would be a great full frame camera. But it just happened to be the unlucky astro 6d.

Have you tried to shoot some DSOs using your 6D and stack the images? I wouldn't use ISO higher than 1600 for astrophotography.



#24 galacticinsomnia

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Posted 12 May 2022 - 02:38 PM

Normal, Optimized, Etc etc are of course filled with subjectivity.

There is nothing wrong with having noise. There are plenty of variables that contribute to noise.  It may be to your benefit to focus more on capturing plenty of signal, and let shooting and post work determine your levels of noise.

Clear Skies !!



#25 zernikepolynomial

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Posted 13 May 2022 - 11:31 PM

I appreciate the advice guys, but like I said, I have a while to wait for my OTA. I'll look at more reliable sources for canon 6d's, and I am also looking at used Nikon d600's or other full frame cameras with good low light ISO. 




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