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04-10-2014, 09:58 AM   #1
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Image Color Gradation, Problem?

Hi all,
I have been looking for this problem for hours now and I can't find another post that is similar, so here goes...

Almost a week ago, I got a great deal on a K-20D from Ebay. (I know the old saying... "If it sounds too good to be true...") It has a fairly high shutter count of 9640 but it was supposedly "reconditioned" at the sellers store... (it's had a few parts replaced and has been cleaned up really nicely too...)

I've taken nearly 200 pictures with it already and it wasn't until I took that "award winning" sunrise picture, this morning, that I noticed that there is a verticle line and image density gradation on the left side of the image (right side of the sensor...)

A visual check of the sensor showed nothing unusual but when I did some post processing of the image it showed up... (raised the contrast and brightness...)

I have swapped out my SD cards and changed lenses, but the gradation persists... I have also installed the latest firmware and turned off the shake reduction, turned down the ISO setting (to 100) and recharged the battery...

As you can see in the insert of the image, the gradation changes three times before the image evens out...

Here's the image... Any help or suggestions would be greatly appreciated...

Thanks in advance...
Bob



Last edited by bobphoenix; 04-10-2014 at 10:02 AM. Reason: spelling
04-10-2014, 10:17 AM   #2
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Looks like you have done pretty extensive testing. In this case you can either return it ( if possible ) or keep if the sensor issue is not showing up too much. I mean, from the photo you showed it is not that apparent and IF - but that needs to be confirmed - IF this banding shows only in dark really dark places then if the deal on the camera was good AND there is no other issues - I probably would keep it. But if these bands are visible in any tonality and brightness or if there are any other issues - I would probably contact the seller and as to return the camera.

Also it can be helpful if you check one of your FIRST photos that you took with it - this can help you convince the seller that the problem WAS there when you bought it - in contrary to a case where an used camera develops an issue which might be beyond sellers responsibility.

Wish you luck!
--manntax
04-10-2014, 11:41 AM   #3
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Google "K20D Vertical Banding"

I know it is not much solace, but this type of issue has been reported off and on pretty much since the camera debuted. My understanding is that it is due to a hardware defect and was fixable under warranty when the cameras were new. Early version of the K10D had similar problems. Here is a posting you might find interesting:

http://www.dlip.de/?p=53

Are you using Dynamic Range Expansion by any chance?


Steve
04-10-2014, 05:11 PM   #4
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QuoteOriginally posted by stevebrot Quote
Google "K20D Vertical Banding"
Are you using Dynamic Range Expansion by any chance?
Steve
Not sure I understand "Dynamic Range Expansion"... (I'll be sure to deeply research it to see if it beneficial to my situation...
I have tried to reset all settings back to the factory and then start with one change at a time... and, so far I have had some luck with changing the ISO settings...
{Edit} No Steve, I always turn off Dynamic Range when I set up a camera, in favor of selecting a fixed ISO number... (My background is film and I always used Extachrome 64 or Kodacolor 100... that's my comfort zone...)

I'm looking at the vertical banding subject too...

Thanks!

Having just bought this camera, I'm a little freaked out when I first saw this condition. Having come from a K-2000 I was looking for big changes, but for the better not worse!


Last edited by bobphoenix; 04-10-2014 at 07:12 PM.
04-14-2014, 05:54 AM   #5
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Success!!!

You guys (and gals where the case may be...) really rock!!!
I read all the references to verticle banding and a few articles about sensors and ISO setting and found out the following; (and without getting too technical...)
Setting the ISO on high (3200-6400) on the CMOS sensor actually "heats up" the transistors and increases the output to the amplifyer (and increases the gain of the amplifyer too) So, just like any other logic driven device when you heat things up they'll either loosen up and work correctly or they'll fail...

In my case they worked...!

I set the ISO to 6400, left the lens cap on and took a 30 second exposure... The CMOS sensor were going nuts looking for something to trigger them and (not so we would notice) got nice and warm (this action also helped to align all the electrons). The result was the same banding as before but only as bad as when I was taking my pictures at ISO 200.
Then, I set the ISO to 3200 and did the same thing... 3 more times... Each time the banding decreased... I let the camera sit over night and the next morning I went out to shoot some pictures (having reset the ISO to 100) and my results were no banding in the same area of the image...
Being quite happy with those results, I tried the test again by setting the ISO to 3200, leaving the lens cap on and shooting another 30 second esxposure... and... the results are in the attached picture... (NOTE: this picture is enhanced for visibility) I turned u the brightness by 150% and increased the resolution sharpness by 200%...
The areas I marked, I assume, are from light entering the lens cap through the filter ring grips...
I should say also, that during this process, I did pixel mapping between each test too... But, I'm not sure how much effect that had on the result...


Compared to the first picture I posted... I am thrilled with the results...
04-14-2014, 06:58 AM   #6
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In short: An amazing example of Power-User mode ON
congratulations !
--manntax

QuoteOriginally posted by bobphoenix Quote
You guys (and gals where the case may be...) really rock!!!
I read all the references to verticle banding and a few articles about sensors and ISO setting and found out the following; (and without getting too technical...)
Setting the ISO on high (3200-6400) on the CMOS sensor actually "heats up" the transistors and increases the output to the amplifyer (and increases the gain of the amplifyer too) So, just like any other logic driven device when you heat things up they'll either loosen up and work correctly or they'll fail...

In my case they worked...!

I set the ISO to 6400, left the lens cap on and took a 30 second exposure... The CMOS sensor were going nuts looking for something to trigger them and (not so we would notice) got nice and warm (this action also helped to align all the electrons). The result was the same banding as before but only as bad as when I was taking my pictures at ISO 200.
Then, I set the ISO to 3200 and did the same thing... 3 more times... Each time the banding decreased... I let the camera sit over night and the next morning I went out to shoot some pictures (having reset the ISO to 100) and my results were no banding in the same area of the image...
Being quite happy with those results, I tried the test again by setting the ISO to 3200, leaving the lens cap on and shooting another 30 second esxposure... and... the results are in the attached picture... (NOTE: this picture is enhanced for visibility) I turned u the brightness by 150% and increased the resolution sharpness by 200%...
The areas I marked, I assume, are from light entering the lens cap through the filter ring grips...
I should say also, that during this process, I did pixel mapping between each test too... But, I'm not sure how much effect that had on the result...


Compared to the first picture I posted... I am thrilled with the results...
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