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Occasional Contributor
Posts: 5
Registered: ‎03-17-2018

Canon 6D strange coloured and white pixels.

[ Edited ]

First of all, i'm not from the US but from Europe (The Netherlands) but this was the only decent official forum that i could find. 

 

But anyway, i bought a Canon 6D begin 2017 and i do like this camera very much. I use it mainly for landscape, urbex and many other things. 

 

But i found out recently that i have strange pixels on my pictures, especially when it's dark with a longer exposure. Some pictures have it more then other ones. 

 

Here is a example, you can see a lot of strange pixels white and coloured to the left of the picture (tip: right click on it and open in a new tab to see it in fullscreen). I haven't edited this picture yet, this is a JPG from the RAW version, nothing else. I also tried to clean my lens because i thought it was some dust on the lens, but it didn't solved it. How can i solve it, shall i send it back to Canon i still have some warranty, or is this something i can solve myself, since i need my camera next friday again. 

 

LfuFrVY.jpg

Honored Contributor
Posts: 6,128
Registered: ‎08-13-2015

Re: Canon 6D strange coloured and white pixels.

Aside from White Balance and potential light flicker issues, I do not see anything really wrong with the image.

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Occasional Contributor
Posts: 5
Registered: ‎03-17-2018

Re: Canon 6D strange coloured and white pixels.

[ Edited ]

I tried to mark all the strange pixels, watch it in fullscreen otherwise you wont see it. Some are blue, some are red but the most are white. 

 

asfaasfasf.jpg

Super Contributor
Posts: 174
Registered: ‎10-21-2016

Re: Canon 6D strange coloured and white pixels.

They are hot pixels, you will get them with any camera when using long exposures or/and high ISO. As you haven't given any exposure details it is difficult to know if this is normal or not.

A lot of raw converters remove them automatically during processing.

Occasional Contributor
Posts: 5
Registered: ‎03-17-2018

Re: Canon 6D strange coloured and white pixels.

[ Edited ]

ISO - 400

Exposure - 30 sec 

 

I rarely use high ISO. 

Esteemed Contributor
Posts: 4,173
Registered: ‎06-25-2014

Re: Canon 6D strange coloured and white pixels.


@Ray-ukwrote:

They are hot pixels, you will get them with any camera when using long exposures or/and high ISO. As you haven't given any exposure details it is difficult to know if this is normal or not.

A lot of raw converters remove them automatically during processing.


I don't see those as hot pixels. A hot pixel will show up under any conditions, at a predictable spot on the sensor and usually at full brightness. And even one hot pixel on a modern-day sensor is a pretty rare occurrence. I think what you're looking at is just ordinary random shadow noise, from a long exposure at high ISO. The 6D has a "long exposure noise reduction" capability, doesn't it? Why not try that?

Bob
Boston, Massachusetts USA
Occasional Contributor
Posts: 5
Registered: ‎03-17-2018

Re: Canon 6D strange coloured and white pixels.

I will make some test pictures later today with long exposure noise reduction and see if it fixed the problem. 

Esteemed Contributor
Posts: 3,369
Registered: ‎06-11-2013

Re: Canon 6D strange coloured and white pixels.

There are many different kinds of noise (speaking generally) and this includes stuck pixels, pattern noise, but there is also noise from quantum effects that cannot be avoided.

 

It's usually easy to clean up.  You can also enable long-exposure noise reduction (which causes your camera to take a second exposure at the same length but with the shutter closed (this is a 'dark' frame) and it subtracts the 'dark' frame from the 'light' frame to eliminate these pixels.)

 

Every digital camera sensor will do this.  We deal with this in astrophotography (where long exposures are the norm) all the time.  

 

Whatever you used to do the RAW -> JPEG conversion looks like it tried to apply sharpening becuase I'm seeing donut rings around the pixels that wont be there in the RAW image (that's typically a result of sharpening.)

 

 

Tim Campbell
5D III, 5D IV, 60Da
Honored Contributor
Posts: 6,128
Registered: ‎08-13-2015

Re: Canon 6D strange coloured and white pixels.


@Toonen1988wrote:

ISO - 400

Exposure - 30 sec 

 

I rarely use high ISO. 


Okay, now I see it.  Is this a new behavior, or have you just discovered it? I have never observed anything quite like this. I see both a red and a white spot under the raised hand, near the center of the image.

 

Take some test shots of simple scenes at a variety of shutter speeds, too. Take shots that make it easy to very if the noise is in the same place, or if it moves around.

 

I take long exposures with my 6D quite a bit, never use noise reduction, and have never observed this type of noise.

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
VIP
Posts: 8,897
Registered: ‎12-07-2012

Re: Canon 6D strange coloured and white pixels.

There is some 'noise' visible in the image, but the red and blue specs are, I think, hot/stuck pixels. They can be caused by heat build up on the sensor, which would certainly be more of an issue with long exposures.  And probably not there in normal exposures.

The healing tool or clone stamp would probably be the best way to get rid of them.  You might be able to use the dust mapping application to fix them.  If they are more random, you might try the patch tool in Photoshop

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