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Old 18-01-2014, 10:36 AM
Blake (Blake)
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Question Canon EOS 6D Hot Pixels

Hi everyone,

Before we get started, yes I do know about the manual sensor clean fix for mapping out hot pixels, and firmware is up to date.

I bought my brand new Canon EOS 6D last week and have been experimenting with some long exposure night photography and learning my way around the camera (this is my first dslr). I read tonnes of reviews about the excellent low noise performance of the 6D, and after seeing some photos taken by other users, and by the renown Mike Salway, I decided to grab one for myself.

After the second night out testing different exposure times and ISO settings, I noticed a bright white pixel in live view. I did the manual sensor clean trick, and this seemed to mask the problem.

A couple of nights later when I finally got a clear night, I was out again playing around with the 6D, and I noticed another bright pixel in a different spot (it's still there now). After seeing this I thought I'd take a closer look at what was going on. I took a few more photos and headed in to my pc to take a look. When I viewed the photos full screen, I noticed a bunch of hot pixels.

The next night I took some more images, and the hot pixels remained in the same spots. Since I'd already done one manual sensor clean/remap, I was bit hesitant at doing it a second time, especially after people have claimed they've never had a hot pixel on their 6D.

So, I decided to do some tests. Camera settings for the test matched those of the previous nights (no long exposure noise reduction, raw images, high ISO speed NR standard). Tests were carried out at an ambient temperature of approx. 28C, fitted with a Canon 24-105mm lens, with lens cap and lens bag covering lens, and viewfinder covered to prevent stray light leakage. The camera had been off for 24 hours before the tests began, so the sensor was definitely not hot, and by the end of the tests, no heat could be felt thought the camera body.

I've shared the link below to my Google Drive, containing all 27 raw test images taken. I'm hoping some others with a 6D can share their experiences and perhaps carry out the same tests under similar conditions to get an idea for myself and others who may have bought, or be looking at buying a 6D, an idea of what sort of sensor quality/number of hot pixels is normal for this camera.

https://drive.google.com/folderview?...1U&usp=sharing

10 seconds - ISO 100 - IMG0293.CR2
10 seconds - ISO 200 - IMG0294.CR2
10 seconds - ISO 400 - IMG0295.CR2
10 seconds - ISO 800 - IMG0296.CR2
10 seconds - ISO 1600 - IMG0297.CR2
10 seconds - ISO 3200 - IMG0298.CR2
10 seconds - ISO 6400 - IMG0299.CR2
10 seconds - ISO 12800 - IMG0300.CR2
10 seconds - ISO 25600 - IMG0301.CR2
-------------------------------------------------------
20 seconds - ISO 100 - IMG0302.CR2
20 seconds - ISO 200 - IMG0303.CR2
20 seconds - ISO 400 - IMG0304.CR2
20 seconds - ISO 800 - IMG0305.CR2
20 seconds - ISO 1600 - IMG0306.CR2
20 seconds - ISO 3200 - IMG0307.CR2
20 seconds - ISO 6400 - IMG0308.CR2
20 seconds - ISO 12800 - IMG0309.CR2
20 seconds - ISO 25600 - IMG0310.CR2
-------------------------------------------------------
30 seconds - ISO 100 - IMG0312.CR2
30 seconds - ISO 200 - IMG0313.CR2
30 seconds - ISO 400 - IMG0314.CR2
30 seconds - ISO 800 - IMG0315.CR2
30 seconds - ISO 1600 - IMG0316.CR2
30 seconds - ISO 3200 - IMG0317.CR2
30 seconds - ISO 6400 - IMG0318.CR2
30 seconds - ISO 12800 - IMG0319.CR2
30 seconds - ISO 25600 - IMG0320.CR2

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  #2  
Old 18-01-2014, 10:39 AM
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One comment - ambient 28C is quite hot. You see more noise in warmer conditions. That may be different to hot pixels though.

Perhaps you got a dud and should get it replaced.

Greg.
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Old 18-01-2014, 10:45 AM
Blake (Blake)
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Yeah I'm not sure, that's what I'm hoping to decide from others results/recommendations. It is summer and it is warm, but the camera was in an air conditioned house and was cool to the touch.

BTW you'll have to download the raw images from my Google Drive to view hot pixels.
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Old 18-01-2014, 11:30 AM
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I have used quite a few digital cameras in the last few years. New hot pixels appearing is not normal behaviour for a new camera no matte the brand or model.

Sensors do degrade over time, they can get damage from radiation, cosmic rays but its a slow process and to be honest I have never seen that even on an old DSLR. I see it on CCD cameras over time very slowly.

Greg.
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Old 18-01-2014, 01:57 PM
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2stroke (Jay)
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I would say its just the heat, DSLR just suck in high temps without cooling hence why cds make astro cooled models. You could try a cooler box, really though dslr's weren't made for the job, in winter you have temp's on your side though. Test it by putting it in the refrigerator and see for your self Best solution go with a tec ccd or a tec cooled dslr but i'am sure the dslr crowed will be up in arms over this comment haha.

Anyhow if the refrigerator test fails then send it back as it could be a bad ground somewhere or emf issue, though i have only had this happen once with a modded 1100d i did.
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Old 18-01-2014, 05:03 PM
Blake (Blake)
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Quote:
Originally Posted by 2stroke View Post
I would say its just the heat, DSLR just suck in high temps without cooling hence why cds make astro cooled models. You could try a cooler box, really though dslr's weren't made for the job, in winter you have temp's on your side though. Test it by putting it in the refrigerator and see for your self Best solution go with a tec ccd or a tec cooled dslr but i'am sure the dslr crowed will be up in arms over this comment haha.

Anyhow if the refrigerator test fails then send it back as it could be a bad ground somewhere or emf issue, though i have only had this happen once with a modded 1100d i did.
I'm not 100% sure it is heat. I don't know, it just seems strange that they are in the same place for all ISO speeds up to 3200, getting worse with increased ISO and exposure time. Doesn't seem to make a difference if I take one long exposure alone, or twenty long exposures. From ISO 6400 up there are some white spots but the red, green, and blue pixels all but disappear.

It would be helpful if the Canon support request form on their website actually worked. I might call them on Monday if I don't get stuck at work, and I might call JB Hi-Fi in Newcastle and see if they can exchange the body. Then there's always the risk of getting a worse one.
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Old 18-01-2014, 05:39 PM
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Have to agree, at 28, it is just to hot regardless of the ISO settings and exposure time, even on the coldest nights, at temps of 3-4 degrees I would not exced 400 Iso, and still some hot pixles would be noticeable.

But that is just MHO.

Leon
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Old 18-01-2014, 07:32 PM
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My 300D is unusable at 30'C. I know it's old but once the heat gets that high most sensors are doing very badly.
-Cam
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Old 19-01-2014, 12:18 PM
Blake (Blake)
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Well that really sucks if it is just temperature. Kind of ruins the whole point of any 30s long summer night exposure shots at ISO 400 if there's going to be 50 odd bright red, blue, and green dots over your image.

Maybe I should try a remap again? It would be nice to know if some other 6D owners had to remap at all.
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Old 19-01-2014, 05:16 PM
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What's weird is the brighter hot pixels disappear going from ISO 3200 to ISO 6400+. There must be some high ISO noise reduction going on above ISO 3200. If you could find a setting to apply it to ISO 3200 and less that would help? Sorry I don't have a 6D so not familiar with the menu but that's what it looks like to me.
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Old 19-01-2014, 05:31 PM
Blake (Blake)
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Quote:
Originally Posted by cometcatcher View Post
What's weird is the brighter hot pixels disappear going from ISO 3200 to ISO 6400+. There must be some high ISO noise reduction going on above ISO 3200. If you could find a setting to apply it to ISO 3200 and less that would help? Sorry I don't have a 6D so not familiar with the menu but that's what it looks like to me.
That's exactly what I don't understand. There's still a few bright coloured dots at ISO 6400+ but I'm pretty sure that's normal and will be removed during processing.

The only noise reduction feature that was enabled was the high ISO noise reduction setting which was set to standard. As far as I know this applies to all images. Even with it disabled completely I still get the same results.
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Old 19-01-2014, 09:09 PM
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I normally use ISO 400, 800 and 1600 and have a number of darks for these at various times. For the matches at 10 and 30 seconds, my images look very similar to yours. Most of the image temps range from 22 to 27 degrees.

I just did a test at ISO 6400 at 30 sec... (temp here is about 27) and it was like yours - no noise (as in I can not see ANY noise on the black image). It's much clearer than any other dark I've done at the lower ISO. I do not have long exposure noise reduction on, but looking the properties of the image it does have the high ISO noise reduction on standard. Haven't tried the extra test as you did - I was just surprised by that result.

...time passes as I test things...

I did some more darks for 30 sec - 3200, 1600, 800 - all have noise like my other darks. I did one for 25600 and it has far less noise than the lower ISO images.

I'll have to try an ISO6400 night shot sometime to see how it looks.
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Old 19-01-2014, 09:28 PM
Blake (Blake)
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Quote:
Originally Posted by lazjen View Post
I normally use ISO 400, 800 and 1600 and have a number of darks for these at various times. For the matches at 10 and 30 seconds, my images look very similar to yours. Most of the image temps range from 22 to 27 degrees.

I just did a test at ISO 6400 at 30 sec... (temp here is about 27) and it was like yours - no noise (as in I can not see ANY noise on the black image). It's much clearer than any other dark I've done at the lower ISO. I do not have long exposure noise reduction on, but looking the properties of the image it does have the high ISO noise reduction on standard. Haven't tried the extra test as you did - I was just surprised by that result.

...time passes as I test things...

I did some more darks for 30 sec - 3200, 1600, 800 - all have noise like my other darks. I did one for 25600 and it has far less noise than the lower ISO images.

I'll have to try an ISO6400 night shot sometime to see how it looks.
Thanks for the reply! Well if you're seeing similar results, maybe I have nothing to worry about. I haven't tried out taking any darks and using them to process any images yet, so that might explain why the images you've posted in the astrophotography forums here don't show any noise.

I was comparing my images to the ones Mike Salway took here to test the long exposure noise for the 6D. If you look at the full res jpeg image there's a bunch of hot pixels, but none that are really bright like the test images I took. That's why I was concerned.

I was surprised by the lower noise at ISO 6400 too, especially considering every mention of hot pixels/noise I could find in the internet referred to high ISO settings.

I got a bit of amp glow from ISO 25600, and a fair bit of noise for a 30s exposure, but that was the last test image I took so the sensor was probably a bit warm.

I tried out some shots last night to compare ISO 3200 and ISO 6400 with different shutter speeds to gather the same amount of light. The ISO 6400 looked about as clean as the ISO 3200, but just didn't have the bright red, green, and blue pixels.

Interesting...
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Old 19-01-2014, 10:13 PM
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Nice topic !
I bought a 6d on New Years Eve day and am very happy with it.

At ISO 6400 noise is negligible, like 1600 on the 7d for 4-8 sec exposures of a (moderately light polluted) sky.
But it is winter here so a high temp test is yet to be done. Next month I go to South Africa making shots of a real dark sky.

But in Feb 2012 in Bali (yes 25-30 C) I took 30 sec and 1 minute frames with my (then 4 years old 40d) but got no extra hot pixels at 1600 and 3200.
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Old 20-01-2014, 11:40 AM
Blake (Blake)
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Quote:
Originally Posted by skysurfer View Post
Nice topic !
I bought a 6d on New Years Eve day and am very happy with it.

At ISO 6400 noise is negligible, like 1600 on the 7d for 4-8 sec exposures of a (moderately light polluted) sky.
But it is winter here so a high temp test is yet to be done. Next month I go to South Africa making shots of a real dark sky.

But in Feb 2012 in Bali (yes 25-30 C) I took 30 sec and 1 minute frames with my (then 4 years old 40d) but got no extra hot pixels at 1600 and 3200.
Good to hear! How cold is winter there? I've seen some good pictures taken with cameras like the 40D but I haven't seen many RAW images to see noise. Also have you done many long exposures, like 30 minute exposures or anything that would get the sensor a bit warm?
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Old 21-01-2014, 09:23 AM
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What software are you using to decode/view the CR2s? Ideally, you should be using DPP.

When using Digital Photo Professional, it applies a different amount of luminance and chrominance noise reduction (0 to 20), based on the ISO the image was shot at. I absolutely love this feature. It usually gets it bang on.

On the 5D Mark II, it applies 0/0 on ISO-100, but, on the 5D Mark III, it applies 1/1 at ISO-100.

The higher the ISO you shoot at, the greater the noise reduction that is applied in DPP. From memory, ISO-3200 on the 5D Mark III, it applies 6/7.

When I get home, I'll download your images and have a play around with them in DPP.

H
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Old 21-01-2014, 11:00 AM
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Nikolas (Nik)
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the images are jpgs of the cr2
Any chance of posting the actual cr2 files?
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Old 21-01-2014, 04:37 PM
Blake (Blake)
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Quote:
Originally Posted by Octane View Post
What software are you using to decode/view the CR2s? Ideally, you should be using DPP.

When using Digital Photo Professional, it applies a different amount of luminance and chrominance noise reduction (0 to 20), based on the ISO the image was shot at. I absolutely love this feature. It usually gets it bang on.

On the 5D Mark II, it applies 0/0 on ISO-100, but, on the 5D Mark III, it applies 1/1 at ISO-100.

The higher the ISO you shoot at, the greater the noise reduction that is applied in DPP. From memory, ISO-3200 on the 5D Mark III, it applies 6/7.

When I get home, I'll download your images and have a play around with them in DPP.

H
I'm just using DPP to view the raw files. You can see the bright pixels when you view images in DPP and on the camera.

I just had a look then at the luminance and chrominance noise reduction, and for the ISO3200 images it applies 9/11.

If you could download them and have a look and see what you think, that would be awesome!


Quote:
Originally Posted by Nikolas View Post
the images are jpgs of the cr2
Any chance of posting the actual cr2 files?
If you click the link to my Google Drive it will open a thumbnail gallery of all the images, then if you click an image it will go full size, then you should be able to click the download button on the bottom right and it will download the full CR2 file

Thanks for the replies!
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Old 27-01-2014, 10:18 PM
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Has anyone had a chance to take a look at any of the pics yet?

I spoke to Canon, and they had a look and just told me to turn on the long exposure and high ISO noise reduction options. Though I don't really want to wait an hour for a 30 minute exposure to process if I shouldn't have to. They said I can send it in for them to take a look but they probably wont do anything with it.

Also, I got Photoshop CS6 and opened the backyard nightscape RAW images using the CameraRaw plugin, and it seems to have removed the bright pixels and any blotchy noise that was visible in DPP. Maybe I should just deal with it during processing?
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