The Red Line

Started Dec 31, 2010 | Discussions
Walter S Matthews Veteran Member • Posts: 3,311
The Red Line

In an earlier post, , I posted a JPG photo taken with my Pentax 645D at the lowest resolution the camera can make.

Referring to my 1600 post, l4nc noted that there is a red line that run horizontally across the black area of the photo about 1/6 of the way up from the bottom.

First thank you l4nc for finding it.

i have tried to characterize it as best as I could and I will present what I now so far/

First, i cannot find the red line when ti runs over areas in th ephoto that ate light. Perhaps it is there in the lighter areas but I cannto see it. However, when it is there, it is clearly visible in darker areas. Even when it is visible in darker areas, when the area of the photo gets lighter I cannot find it

The first place it was found for me by l4nc was in a JPG file taken at the lowest resolution possible for the camera so I started there. The following post is a crop from a shot where the backdrop is half way down and the background is black.

The red line appears about as clearly as it did in the original post where l4nc first pointed it out.

The next crop is of that same area that was taken without moving the camera at iso 1600 in jpg and at the highest resolution the camera can make. The line is not more distinct and is obviously a aingle pixel wide and it ends, that is the red line ends at a specific location where there are several pixels affected and that defect area is actually visible in light areas of the photograph.

The next post is a photograph taken in jpg at iso 200 in high resolution and i cannot find the red line anywhere.

I was unable to find the red line in any photo taken at iso 200

The next post is disturbing and suggests to me that the camera may have to go back. It is a photo taken in RAW at 1600

Although the line appears to be less pronounced from the RAW photo at 1600, that red line is clearly there and it will clearly affect any photo taken at that iso. Similarly I was unable to find the red line in any photo taken at iso 200, regardless of total resolution or of mode of shooting

I have not contacted Pentax yet but I will do so on Monday or Tuesday. I have no idea what is really causing the red line, although like the resto of you, I have suspicions. In any event I will just have to see what they have to say about it.

At least now I have extensive data about the issue and it will be more difficult for them to try to run around the problem by ignoring it and then saying they cannot find it.

It is possible that the line defect can be maped out and I am tempted to use the utility that is provided in one of the tool menues but i want to be sure I can prove t them that is real and reproducible and if they suggest a fix I will try their fix but none of my own working on it now...

tcom Veteran Member • Posts: 7,496
Re: The Red Line

Hi Walter

I had a similar problem with the K-7. A green verticale line was appearing when the sensor temperature raised above 28°. The line was starting to get visible at 1600iso at 28°, at 34° sensor temperature, it was even visible at lower iso.

I contacted the service of Pentax and after a few weeks, a firmware update was solving the problem.

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godfrog Senior Member • Posts: 1,463
Re: The Red Line

On a camera like that, I'd probably try to get it repaired even if would not affect you during normal use. It would bring down the resale value of the camera considerably, which might matter when Pentax tempt you with their next 645D camera

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OP Walter S Matthews Veteran Member • Posts: 3,311
Re: The Red Line

Yes, they have to get it fixed but i figured i would not be able to get them to pay attention over the holidays,

awaldram Forum Pro • Posts: 13,271
Re: The Red Line

Does the 645d have pixel remapping, If so I'd run that first as if its just a stuck pixell @ iso1600 then that all Pentax service will do.

Its all any manufacturer would do but Pentax give users the capability.

I know it a full column but that could still be one pixel holding the column address and not releasing

Of cause if its more systematic than individual then new firmware may be required.
My Photo Stream

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OP Walter S Matthews Veteran Member • Posts: 3,311
Re: The Red Line

yes, i already mentioned that is something I guess will happen but i wanted to get it on record with their service department in case it turns out to be something even more serious in the future

I can trace the defect to its origin and it is more like 6 to 8 pixels that are not working and just mapping them out may not fix it.

We will see.....

Thank all of you for the interest....

ozdean Forum Pro • Posts: 26,179
Re: The Red Line

I am sure Pentax would want to know about this so let us know how you get on Walter.
Regards Dean - Capturing Creation

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OP Walter S Matthews Veteran Member • Posts: 3,311
Re: The Red Line

I was able to get through to the Pentax guy who owns the 645D problems and it was suggested that I perform the Pixel mapping. I had planned to do that anyway but didn't realize it is as simple to do as it is. Apparently there is a map in the camera of a completely black detector and any pixel that does not show as black when it is mapped in the program will be removed by mapping interpolation with adjacent pixels -if it works.

The Pentax guy was very nice, willing to share what he knew with me and I learned a lot talking to him. Don't need to name him here but I do appreciate his time and most of all his really great attitude about my complaint/comments. Believe me, in the past- Nikon has been a lot less-how to say it, congenial....

Apparently Pentax USA got 5 units in and one unit went to DPREVIEW. It is still there at DPREVIEW now and he has no idea what, if anyting, they are doign with it. Two of the units have been allocated to the repair department to take apart if necesary for comparison if uintis come in for repair and two units are to send to customers who need to have their cameras repaired. He has been using the camera now for about three weeks and has much the same reaction to it I have.

Fortunate for me I do not need any repair.

After mapping the red line is gone, gone , gone and that makes me very, very , very happy.

I did try to remove it from a few photos just to see if I could and when the pattern is complex, forget it. I was ablt to do it but it took a long time to get it right.

So-RED LINE is ....GONE.

ropen Senior Member • Posts: 1,479
Re: The Red Line

Excellent news, Walter!

I remember that Ned (I think Ned) said that every buyer of the 645D in the US will be automatically enrolled in the Professional Services Program and will have at his/her disposal a dedicated support person.


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ozdean Forum Pro • Posts: 26,179
Re: The Red Line

Great news Walter - keep posting please!
Regards Dean - Capturing Creation

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duncsuss Contributing Member • Posts: 933
glad it's fixed now

Walter -- that's great news; I believe your approach to addressing the problem and getting a solution was correct from the outset.

Hope you enjoy many years of photography with your 645D -- please share the highlights from time to time.

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OP Walter S Matthews Veteran Member • Posts: 3,311
Re: glad it's fixed now

LOL-First day of sunshine since I got the camera and I am headed out to shoot something. NO idea what.....I'll post a few. What remains to test is DR and I will test it gainst the Fuji S5 for DR. My initial testing shows tha it does not have nearly the same or even close to the highlight range the S5 does but I haven't proven it.

Jim King
Jim King Veteran Member • Posts: 8,584

What??? No hissy fit, no heated declaration that Pentax should never have released such a faulty body, no flaming of anybody, no threat to return the camera and abandon Pentax? You must be in the wrong forum!

Seriously, your handling of this problem(and Pentax's response) were mature and thoughtful. If only some of the perpetual whiners here could respond similarly...

(I'll may be flamed for this post, but it's worth it.)
Jim King - Retired Colormonger - Suburban Detroit, Michigan, USA; GMT -5h (EST)
Pentaxian for over 45 years.

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A fanatic is one who can't change his mind and won't change the subject.

  • Sir Winston Churchill

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The difference between genius and stupidity is that genius has its limits.

  • Albert Einstein

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Dcuk Contributing Member • Posts: 877
Re: The Red Line

Hi Walter,

It's great that the pixel mapping cured the problem. I mentioned a little while ago that the 645D Image Resource used, also had/has a similar problem.

If you ever speak to the helpful gentleman at Pentax again, he may be interested to know that two 645D showed the line in higher ISO photographs.

You must have been a very good boy last year, for Santa to bring you a 645D, even if you did buy it yourself.

Best wishes,


l4nc New Member • Posts: 9

Congratulations Walter!. Thank you very much for your post!. Sorry for answering so late, I've just found this thread with the "search" tool, I expected (and been looking for) your response in your original thread and did not realize about this one.

I'm planning to get a new camera next Spring, and considering 645D as a serious option. I'm not a pro, just an amateur, so I don't need it, just want it to enjoy it.

Of course price is a factor to consider, and other cameras (D800(??), SD1) are tempting me too, though not as much as 645D.

Enjoy your camera!.

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