# Hot pixel in jpeg file but not raw?



## Replytoken (Jan 9, 2014)

OK.  I am a bit stumped by this.  I am evaluating a new camera with a 16MP APS-C sensor that does not have a pixel remapping function.  I shot a handful of test images in the raw+jpeg setting under a variety of conditions.  Upon examining the images in LR, PSE8 and Faststone IV, all the jpeg files show a hot pixel in the exact same location.  But the corresponding raw files have no hot pixels visible.  This seems very weird, and somewhat backwards from what one would expect, as these types of things are usually only visible in the raw files and not the derivative jpegs created by the camera.  I am curious to know if this is a fault of the image processor or the sensor.  I realize that hot pixels are not uncommon, but usually they can be mapped out.  The camera is brand new, and I could try to exchange it, but before I exercise that option, I was wondering what others think.  I normally shoot raw, but if I did shoot jpeg files, it is usually in a situation where I do not have time to edit the files, so this hot pixel would remain.  It is only one pixel, but it is red, and starts to be visible at 50% magnification, not quite what I would call extreme pixel peeping given the size of monitors today.  Any thoughts?

--Ken


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## Tony Jay (Jan 9, 2014)

Replytoken said:


> ... Any thoughts?
> --Ken


Nada!
Confused as all heck.
Lets see if the brains trust has the lowdown on this one.

Tony Jay


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## Replytoken (Jan 9, 2014)

Tony Jay said:


> Nada!
> Confused as all heck.
> Lets see if the brains trust has the lowdown on this one.
> 
> Tony Jay



You are not the only one who is confused.  I contacted somebody who I thought might know the answer, and they were stumped as well.  I will post if I find out anything useful.

--Ken


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## Victoria Bampton (Jan 9, 2014)

I can't speak for Faststone, but ACR/LR maps out hot pixels in raw files.


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## Replytoken (Jan 9, 2014)

Victoria Bampton said:


> I can't speak for Faststone, but ACR/LR maps out hot pixels in raw files.



Thank you, Victoria.  This is what somebody else wrote to me as well this morning.  So, while we think that we may be seeing the raw file, it sounds like most raw converters do a bit more than we think when they present a file for viewing.  Now, I need to decide if that hot pixel is going to drive me crazy or not.  I know they are not uncommon, but a red one in the middle of the image is not exactly "tucked away" where it may go unnoticed.  Just my luck.

Thanks,

--Ken


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## clee01l (Jan 9, 2014)

I'm not sure that FastStone Image Viewer does any more than display the embedded JPEG in RAW file formats  Which surprises me that the FSIV displays healed hotspots.


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## Replytoken (Jan 9, 2014)

clee01l said:


> I'm not sure that FastStone Image Viewer does any more than display the embedded JPEG in RAW file formats  Which surprises me that the FSIV displays healed hotspots.



You are correct, Cletus.  But, when I read the files in LR and PSE8, the pixel was visible in the jpeg file, but not in the raw (native DNG) file.  Now you have me wondering if I only looked at the DNG files in the Library module, or if I also opened them in the Develop module as well.  I'll need to check when I get back to my computer this evening.  In FSIV, the pixel showed up in the jpeg.  The embedded jpeg in the DNG was a very low resolution file and I could not tell if the pixel was visible in that file in FSIV.

--Ken


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