# 7D II Hot Pixel in Jpeg but not RAW



## bluenoser1993 (Jul 23, 2015)

I recently purchased a used TSE 17 and just had a chance to do a little testing and experimenting with the tilting. I forgot to change my camera settings and so ended up with both full quality Jpeg and RAW files while shooting the test shots. When moving around the 100% image to compare DOF with tilt vs no tilt, I discovered two hot pixels. In the screen shot I've put both versions of the same image, RAW to the right with no post processing to either, the in camera Jpeg was set to landscape. I chose this frame because the spot was brightest due to the longer exposure, it was much fainter in the 1/30 sec shots.

This seems unusual to me, does anyone have any explanation?


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## neuroanatomist (Jul 23, 2015)

Aperture, like most RAW converters, automatically detects and removes hot/stuck pixels. The in-camera JPG engine does not. 

You can force the camera to remap them, which will result in them being removed from JPGs (at least until new ones pop up). With body cap or lens cap in place, start a manual sensor clean and let it sit for ~30 s before turning off the camera.


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## Mt Spokane Photography (Jul 23, 2015)

neuroanatomist said:


> Aperture, like most RAW converters, automatically detects and removes hot/stuck pixels. The in-camera JPG engine does not.
> 
> You can force the camera to remap them, which will result in them being removed from JPGs (at least until new ones pop up). With body cap or lens cap in place, start a manual sensor clean and let it sit for ~30 s before turning off the camera.



Beat me to it!

+1


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## bluenoser1993 (Jul 23, 2015)

Mt Spokane Photography said:


> neuroanatomist said:
> 
> 
> > Aperture, like most RAW converters, automatically detects and removes hot/stuck pixels. The in-camera JPG engine does not.
> ...



Thank You Gentleman, I didn't realize the converters had auto detection for that.


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## Mt Spokane Photography (Jul 23, 2015)

bluenoser1993 said:


> Mt Spokane Photography said:
> 
> 
> > neuroanatomist said:
> ...


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## pj1974 (Jul 24, 2015)

Mt Spokane Photography said:


> neuroanatomist said:
> 
> 
> > Aperture, like most RAW converters, automatically detects and removes hot/stuck pixels. The in-camera JPG engine does not.
> ...



Great responses ... and I find this really interesting. I was aware of this information... i.e. I was aware of the 'mapping of hot pixels' by software (don't some cameras also have this function?)

My 'follow-on' question is.. what actually happens to those 'pixels' (in the image). Are the 'hot pixels' replaced by 'nearest neighbour'? Surely it doesn't make it 'black' does it?

Or is this were 'dark matter' and 'the void and vacuum of space' enter our images? (and why the universe is expanding?! lol) 

Ok.. serious question (with some fun thrown in, in the above paragraph).

Looking forward to hearing from folks... 

Paul


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## Sith Zombie (Jul 24, 2015)

pj1974 said:


> Mt Spokane Photography said:
> 
> 
> > neuroanatomist said:
> ...



Yes, interesting! Also, to further your question: I wonder what happens when a remapped pixel becomes unstuck? Does it continue using the 'remapped algorithm' or just revert to functioning how did did before it was stuck?


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## Valvebounce (Jul 24, 2015)

Hi Folks. 
I always thought mapped out pixels would have a value assigned relative to their surrounding pixels via some sort of algorithm. I was also under the impression that stuck pixels are not really stuck as in can be freed up but have failed as in full on or full off, no going back from broken. 
Waiting patiently to be educated in the error of my ways! ;D Or in other words corrected. 

Cheers, Graham. 



Sith Zombie said:


> pj1974 said:
> 
> 
> > My 'follow-on' question is.. what actually happens to those 'pixels' (in the image). Are the 'hot pixels' replaced by 'nearest neighbour'? Surely it doesn't make it 'black' does it?
> ...


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