Large green bands on night shots (K20D)

mateus · 11-03-2012, 03:59 PM

Hi all, I'm after some advance regarding night shots with a K20D.

This evening I drove into the countryside to take few cold night shots but when I downloaded the photos may have green banding on them (mainly on the left of the photo).

Banding is less on ISO100 compared to ISO400 but it's still very noticeable (exposure times where approx 2 minutes).

Any ideas?

Thanks,
Matt

Last edited by mateus; 11-03-2012 at 04:10 PM.

Trapezoid645 · 11-03-2012, 04:11 PM

If I recall correctly, this was a well documented problem with K20D's Samsung sensor what needed to be replaced (warranty covered it at that time). They tried a software patch, but the fix was only marginal.

mateus · 11-03-2012, 05:49 PM

Really? Oh dear.

Well I'll carry on and hope for the best!

mateus · 11-04-2012, 04:09 AM

Maybe it's the cold weather too? Apparently taking long exposures at below 2c causes banding!

Basie · 11-04-2012, 08:25 AM

I could not see any the green banding on my monitor, but have had a problem with intermittent green lines as well (https://www.pentaxforums.com/forums/general-technical-troubleshooting/157760-...ines-cast.html).

It was not as cold as during your expedition, but is has not recurred after the firmware update. I must admit, since getting a K5, the K2o does not get a lot of usage any more

Good luck

**pixelsaurus** · 11-04-2012, 12:01 PM

Did you have Noise Reduction turned on or off? Banding can be an issue with some sensors at high ISO and long exposures. You may have to embrace the Dark Side and incorporate darks, (same exposure/ISO as primary exposure but with the camera capped to keep out the light. It becomes a record of the noise characteristics of the sensor), and then subtract them in a program like Deep Sky Stacker or IRIS. Both are freeware.

mateus · 11-05-2012, 02:06 AM

Thanks for all the replies. Certainly the banding is not as bad as the example in your post Basie and I am on firmware 1.05. I'll try again but this time I'll get the sensor warmed up first with a few 30s shots as suggested by another user.

I'm not sure how Deep Sky Stacker works as how does one get a photo of stars without long exposures. I'll read the tutorials with interest.

(Oddly the green band in my example photo is not visible on my cheap work PC monitor but is very visible on my expensive Dell monitor at home.)

Last edited by mateus; 11-05-2012 at 02:15 AM.

11-03-2012, 03:59 PM	#1
mateus Inactive Account Join Date: Apr 2011 Posts: 10	Large green bands on night shots (K20D) Hi all, I'm after some advance regarding night shots with a K20D. This evening I drove into the countryside to take few cold night shots but when I downloaded the photos may have green banding on them (mainly on the left of the photo). Banding is less on ISO100 compared to ISO400 but it's still very noticeable (exposure times where approx 2 minutes). Any ideas? Thanks, Matt Last edited by mateus; 11-03-2012 at 04:10 PM.

11-03-2012, 05:49 PM	#3
mateus Inactive Account Join Date: Apr 2011 Posts: 10 Original Poster	Really? Oh dear. Well I'll carry on and hope for the best! Last edited by mateus; 11-04-2012 at 04:07 AM.

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11-03-2012, 04:11 PM	#2
Trapezoid645 Forum Member Join Date: Apr 2010 Location: Santa Barbara Photos: Albums Posts: 60	If I recall correctly, this was a well documented problem with K20D's Samsung sensor what needed to be replaced (warranty covered it at that time). They tried a software patch, but the fix was only marginal.

11-04-2012, 04:09 AM	#4
mateus Inactive Account Join Date: Apr 2011 Posts: 10 Original Poster	Maybe it's the cold weather too? Apparently taking long exposures at below 2c causes banding!

11-04-2012, 08:25 AM	#5
Basie Pentaxian Join Date: Aug 2011 Location: Windhoek, Namibia Photos: Gallery Posts: 989	I could not see any the green banding on my monitor, but have had a problem with intermittent green lines as well (https://www.pentaxforums.com/forums/general-technical-troubleshooting/157760-...ines-cast.html). It was not as cold as during your expedition, but is has not recurred after the firmware update. I must admit, since getting a K5, the K2o does not get a lot of usage any more Good luck

11-04-2012, 12:01 PM	#6
pixelsaurus Site Supporter Join Date: Jul 2007 Location: Te Kuiti, NZ Photos: Gallery \| Albums Posts: 986	Did you have Noise Reduction turned on or off? Banding can be an issue with some sensors at high ISO and long exposures. You may have to embrace the Dark Side and incorporate darks, (same exposure/ISO as primary exposure but with the camera capped to keep out the light. It becomes a record of the noise characteristics of the sensor), and then subtract them in a program like Deep Sky Stacker or IRIS. Both are freeware.

11-05-2012, 02:06 AM	#7
mateus Inactive Account Join Date: Apr 2011 Posts: 10 Original Poster	Thanks for all the replies. Certainly the banding is not as bad as the example in your post Basie and I am on firmware 1.05. I'll try again but this time I'll get the sensor warmed up first with a few 30s shots as suggested by another user. I'm not sure how Deep Sky Stacker works as how does one get a photo of stars without long exposures. I'll read the tutorials with interest. (Oddly the green band in my example photo is not visible on my cheap work PC monitor but is very visible on my expensive Dell monitor at home.) Last edited by mateus; 11-05-2012 at 02:15 AM.

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