645D dead pixel after 275 exposures - solved!

**The Madshutter** · 04-25-2014, 02:11 AM

Well, it had to happen I guess - I went to Cappadocia for a 4-day shooting, and after coming back home and starting to work on the photographs I found a very nice looking, very bright red line in any image taken after exposure _6450275: since my first image of the trip is _6450263, basically all the 300 images I shot over there got it. Once I got home and I found out, I immediately run a pixel mapping which thankfully solved the problem the first time over. This things happen of course, and I am glad Pentax included a pixel-mapping feature in the 645D which immediately fixed the issue for me. I wasn't expecting it to happen so soon though, which is why I wasn't checking pictures at 100% in the field - sadly so, if I did check now I'd have many less ruined pictures. Oh well, lesson learned: now, all I have to do is fix the red line in the ~60 keepers from the trip...

So I guess the point of this story is, no matter how new your camera is, keep checking for dead pixels - they can creep in when you less expect them!

tim60 · 04-25-2014, 03:18 AM

Sounds like you should be taking this up with the supplier. Warranty type situation. There must be a fault with a sensor to have failure so early.

The pattern with electronic stuff is that they have a high very early failure rate, followed by an extended high reliability interval and then failures increase as they start to get old. The 'bathtub' curve. Warranty is to protect the buyer from the burn in period failures.

**The Madshutter** · 04-25-2014, 04:55 AM

Tim, you are of course right about the failure pattern with electronics - however, in this case, since:

- the issue was just one dead pixel that I could fix with the pixel mapping thing (camera now works perfectly again);
- having Pentax taking care of it will mean for me to be without camera for a while (months perhaps if they'll have to ship it to Japan);
- the camera has 8 more months warranty on it;

I think I'll keep using the camera and see what happens, and eventually send it in later on if more dead pixels will pop up. If not, and if the incident will be confined to the one dead pixel, the better, since otherwise the machine is perfectly fine.

johnyates · 04-25-2014, 01:21 PM

Just had a look at your web site--your pictures are AWESOME!

tim60 · 04-25-2014, 01:36 PM

Originally posted by The Madshutter

Tim, you are of course right about the failure pattern with electronics - however, in this case, since:

- the issue was just one dead pixel that I could fix with the pixel mapping thing (camera now works perfectly again);
- having Pentax taking care of it will mean for me to be without camera for a while (months perhaps if they'll have to ship it to Japan);
- the camera has 8 more months warranty on it;

I think I'll keep using the camera and see what happens, and eventually send it in later on if more dead pixels will pop up. If not, and if the incident will be confined to the one dead pixel, the better, since otherwise the machine is perfectly fine.

Thanks. All said in goodwill.

I had interpreted that you had whole rows/columns that showed trouble, which was rather more disturbing to me.

**The Madshutter** · 04-25-2014, 02:14 PM

Originally posted by johnyates

Just had a look at your web site--your pictures are AWESOME!

Thank you John, I really appreciate it, am glad you enjoyed the site!

---------- Post added 04-26-14 at 12:16 AM ----------

Originally posted by tim60

Thanks. All said in goodwill.

I had interpreted that you had whole rows/columns that showed trouble, which was rather more disturbing to me.

Hello Tim,

you are absolutely right, had I had whole rows or columns off I'd have sent the camera back as fast as I could

Thankfully, I could manage with the (very useful) Pixel Mapping feature. Thanks again!

**Lowell Goudge** · 04-26-2014, 04:34 AM

Just as a note, there are many third party processors that deal with dead pixels also

**The Madshutter** · 04-26-2014, 06:03 AM

Originally posted by Lowell Goudge

Just as a note, there are many third party processors that deal with dead pixels also

This is interesting, do you mind expanding on the topic a bit? Thanks!

**Lowell Goudge** · 04-26-2014, 11:00 AM

Originally posted by Lowell Goudge

Just as a note, there are many third party processors that deal with dead pixels also

Originally posted by The Madshutter

This is interesting, do you mind expanding on the topic a bit? Thanks!

There are plug-ins for dead pixel correction, that are compatible with any adobe (photoshop) compatible program. I forget the one I use linked in with Corey's PSP X but if you do a search on dead/hot pixel correction it is there. I looked for this when my *istD started showing some hot pixels, because there is no pixel mapping to correct this in camera on early DSLRs

Not that I am promoting I but it is just the first entry when I googled hot pixel correction adobe plug in

http://oneslidephotography.com/download-photography-software-hotpixel-adobe-photoshop-plug-in/

Omaha · 04-28-2014, 06:54 AM

My understanding is that every digital camera has numerous dead pixels. They are mapped out as part of the manufacturing/assembly process, so you never know about them. As time goes on, more will die, requiring eventual remapping or some form of post-processing correction.

I don't know how many dead pixels the manufacturers allow to be mapped out in production before the sensor is considered a "dud", but I expect the number is surprisingly high.

04-25-2014, 02:11 AM	#1
The Madshutter Site Supporter Join Date: Mar 2014 Location: Tuscany, Italy Posts: 1,255	645D dead pixel after 275 exposures - solved! Well, it had to happen I guess - I went to Cappadocia for a 4-day shooting, and after coming back home and starting to work on the photographs I found a very nice looking, very bright red line in any image taken after exposure _6450275: since my first image of the trip is _6450263, basically all the 300 images I shot over there got it. Once I got home and I found out, I immediately run a pixel mapping which thankfully solved the problem the first time over. This things happen of course, and I am glad Pentax included a pixel-mapping feature in the 645D which immediately fixed the issue for me. I wasn't expecting it to happen so soon though, which is why I wasn't checking pictures at 100% in the field - sadly so, if I did check now I'd have many less ruined pictures. Oh well, lesson learned: now, all I have to do is fix the red line in the ~60 keepers from the trip... So I guess the point of this story is, no matter how new your camera is, keep checking for dead pixels - they can creep in when you less expect them!

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04-25-2014, 03:18 AM	#2
tim60 Pentaxian Join Date: Apr 2011 Photos: Albums Posts: 8,756	Sounds like you should be taking this up with the supplier. Warranty type situation. There must be a fault with a sensor to have failure so early. The pattern with electronic stuff is that they have a high very early failure rate, followed by an extended high reliability interval and then failures increase as they start to get old. The 'bathtub' curve. Warranty is to protect the buyer from the burn in period failures.

04-25-2014, 04:55 AM	#3
The Madshutter Site Supporter Join Date: Mar 2014 Location: Tuscany, Italy Posts: 1,255 Original Poster	Tim, you are of course right about the failure pattern with electronics - however, in this case, since: - the issue was just one dead pixel that I could fix with the pixel mapping thing (camera now works perfectly again); - having Pentax taking care of it will mean for me to be without camera for a while (months perhaps if they'll have to ship it to Japan); - the camera has 8 more months warranty on it; I think I'll keep using the camera and see what happens, and eventually send it in later on if more dead pixels will pop up. If not, and if the incident will be confined to the one dead pixel, the better, since otherwise the machine is perfectly fine.

04-25-2014, 01:21 PM	#4
johnyates Pentaxian Join Date: Aug 2011 Location: Saskatoon, SK Photos: Albums Posts: 1,345	Just had a look at your web site--your pictures are AWESOME!

04-25-2014, 01:36 PM	#5
tim60 Pentaxian Join Date: Apr 2011 Photos: Albums Posts: 8,756	Originally posted by The Madshutter Tim, you are of course right about the failure pattern with electronics - however, in this case, since: - the issue was just one dead pixel that I could fix with the pixel mapping thing (camera now works perfectly again); - having Pentax taking care of it will mean for me to be without camera for a while (months perhaps if they'll have to ship it to Japan); - the camera has 8 more months warranty on it; I think I'll keep using the camera and see what happens, and eventually send it in later on if more dead pixels will pop up. If not, and if the incident will be confined to the one dead pixel, the better, since otherwise the machine is perfectly fine. Thanks. All said in goodwill. I had interpreted that you had whole rows/columns that showed trouble, which was rather more disturbing to me.

04-25-2014, 02:14 PM	#6
The Madshutter Site Supporter Join Date: Mar 2014 Location: Tuscany, Italy Posts: 1,255 Original Poster	Originally posted by johnyates Just had a look at your web site--your pictures are AWESOME! Thank you John, I really appreciate it, am glad you enjoyed the site! ---------- Post added 04-26-14 at 12:16 AM ---------- Originally posted by tim60 Thanks. All said in goodwill. I had interpreted that you had whole rows/columns that showed trouble, which was rather more disturbing to me. Hello Tim, you are absolutely right, had I had whole rows or columns off I'd have sent the camera back as fast as I could Thankfully, I could manage with the (very useful) Pixel Mapping feature. Thanks again!

04-26-2014, 04:34 AM	#7
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	Just as a note, there are many third party processors that deal with dead pixels also

04-26-2014, 06:03 AM	#8
The Madshutter Site Supporter Join Date: Mar 2014 Location: Tuscany, Italy Posts: 1,255 Original Poster	Originally posted by Lowell Goudge Just as a note, there are many third party processors that deal with dead pixels also This is interesting, do you mind expanding on the topic a bit? Thanks!

04-26-2014, 11:00 AM	#9
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	Originally posted by Lowell Goudge Just as a note, there are many third party processors that deal with dead pixels also Originally posted by The Madshutter This is interesting, do you mind expanding on the topic a bit? Thanks! There are plug-ins for dead pixel correction, that are compatible with any adobe (photoshop) compatible program. I forget the one I use linked in with Corey's PSP X but if you do a search on dead/hot pixel correction it is there. I looked for this when my *istD started showing some hot pixels, because there is no pixel mapping to correct this in camera on early DSLRs Not that I am promoting I but it is just the first entry when I googled hot pixel correction adobe plug in http://oneslidephotography.com/download-photography-software-hotpixel-adobe-photoshop-plug-in/

04-28-2014, 06:54 AM	#10
Omaha Inactive Account Join Date: Jan 2013 Posts: 17	My understanding is that every digital camera has numerous dead pixels. They are mapped out as part of the manufacturing/assembly process, so you never know about them. As time goes on, more will die, requiring eventual remapping or some form of post-processing correction. I don't know how many dead pixels the manufacturers allow to be mapped out in production before the sensor is considered a "dud", but I expect the number is surprisingly high.