Pentax k-7 low light banding - normal or worrying?

zxaar · 02-15-2010, 04:33 PM

my sony r1 had true liveview and when i shot with it, 95% of time liveview was on. So sensor heating up and showing banding is not much of an issue. But sensor heat do contribute to noise (my subjective opinion).

interesting question would be what other pentax cameras show banding. Because my suspect is the way sony sensors are implemented they might not show banding.

Jadran · 02-15-2010, 05:07 PM

Originally posted by zxaar

my sony r1 had true liveview and when i shot with it, 95% of time liveview was on. So sensor heating up and showing banding is not much of an issue. But sensor heat do contribute to noise (my subjective opinion).

interesting question would be what other pentax cameras show banding. Because my suspect is the way sony sensors are implemented they might not show banding.

My guess is that there is varying tolerance to the heat that the K-7 sensors have (quality control?). Could be also that only few are affected, it's hard to say.

As I said, the one that I have now has no problems with banding at all, no meter of LV use, outside temperature, ISO, or any other conditions. But the first one was catastrophe, which was eventually diagnosed by Pentax Service as faulty sensor.

zxaar · 02-15-2010, 05:29 PM

Originally posted by Jadran

My guess is that there is varying tolerance to the heat that the K-7 sensors have (quality control?). Could be also that only few are affected, it's hard to say.

As I said, the one that I have now has no problems with banding at all, no meter of LV use, outside temperature, ISO, or any other conditions. But the first one was catastrophe, which was eventually diagnosed by Pentax Service as faulty sensor.

i was not aware that it could vary camera to camera.

Thanks for your posting , it might be helpful to others. on another forum i frequently visit, there was someone wondering about banding issue with canon 7d.
she did send her files to canon and canon refused to acknowledge problem. i will advice her to try to change her camera body, she might get rid of banding.

asdf · 02-15-2010, 06:05 PM

Originally posted by zxaar

i was not aware that it could vary camera to camera.

Thanks for your posting , it might be helpful to others. on another forum i frequently visit, there was someone wondering about banding issue with canon 7d.
she did send her files to canon and canon refused to acknowledge problem. i will advice her to try to change her camera body, she might get rid of banding.

The pattern may vary, but I suspect the other poster is mistaken. There is no image to back up the claim. It's easy to reproduce the pattern (or show it's not there): just slightly overexpose a gray or black area at the highest ISO setting. To avoid this pattern noise, Sony's latest sensors have an A/D converter per column (or so I read).

EDIT:

"At the same time, however, the following problems occur in conventional CMOS sensors. Although the fixed pattern noise between pixels can be removed by the CDS circuits located at each column, a vertical form of fixed pattern noise oc- curs due to differences between the CDS circuits themselves.
Also a capacitor with a size larger than a certain value is required in the CDS circuit to record and hold the post-CDS signal, and this results in an increase in the area of this circuit. Furthermore, the recorded and stored analog signals are easily influenced by switching noise in the high-frequency band due to the horizon- tal transfer operations.
To resolve these problems, Sony adopted the column-parallel A/D conversion tech- nique. (See figure 2.) "

http://www.sony.net/Products/SC-HP/cx_news/vol47/pdf/featuring47.pdf

Last edited by asdf; 02-15-2010 at 06:20 PM.

Jadran · 02-16-2010, 02:02 AM

Originally posted by asdf

The pattern may vary, but I suspect the other poster is mistaken. There is no image to back up the claim. It's easy to reproduce the pattern (or show it's not there): just slightly overexpose a gray or black area at the highest ISO setting. To avoid this pattern noise, Sony's latest sensors have an A/D converter per column (or so I read).
]

You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7

But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar.

Norman · 02-16-2010, 02:39 AM

Originally posted by Jadran

You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7

But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar.

Hm, except in my case I dont have that prominent green line and my banding is more purpleish.

So is this something I should worry about or is it normal?
This pic is ISO100 (brought up the levels by alot digitally) as the other.

Edit: Correction, I can see a slight tint of the band at ISO3200 when I take a shot with lens cover on. But it's easily hidden by the normal ISO noise, and even more so when bringing levels up.

Jadran · 02-16-2010, 02:53 AM

Yes, in my case banding was much much worse, though in cases when sensor didn't heat up (some first dozen shoots) it was withouth lines and much more simillar to your case. I'm not clever here. If you think that this banding doesn't affect the most of you shoots, then maybe you shouldn't be worried. Or, maybe you could conntact Pentax Service, send them samples of banding and ask for assistance. In this case I had very good experinece with Pentax representative in Croatia and Pentax Europe HQ Service in Paris, France. They were willing to help.

asdf · 02-16-2010, 03:10 AM

Originally posted by Jadran

You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7

But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar.

I see now. That's definitely not noise, but a faulty sensor. The pattern noise I was thinking about were "bands" of slightly different luminance. This kind of thing seems to appear on every camera, except the latest and greatest. Just google "k20d banding" or "k10d banding".

Norman · 02-16-2010, 05:12 AM

It doesnt affect most of my shots, but still annoys me to know it is there. Makes me see things (which probably arent there) but feels like there's a tint of purple/pink at that area when I develop my shots.

Ill probably buy a k-X meanwhile and send my k-7 for service here in sweden.
Got to find my proof of purchase now from fry's. (Camera bought in the US, but I live in Sweden)

cyy47 · 02-16-2010, 11:22 AM

I had the same issue, but only at higher iso.

K7 banding

I sent it back and am anxiously waiting for the replacement.

Asudef · 06-14-2010, 03:36 PM

I just got a K7 used and took some shots last night and discovered this issue. It's pretty noticeable and there seem to be other unrelated issues I'm trying to test out (softness &/or front/back focusing), considering it's their best camera, this isn't acceptable. I bought a K20 used and that thing never had any issues. I haven't updated the firmware yet, would that make a difference?

The seller says he would help with the warranty process since it was local and it's only been a day I'd like to do something about it ASAP.

Is this anything to be worried about? Shot at ISO100 w/ the WR kit lens in low light, f/5.6 @ 1/2s.

r0ckstarr · 06-14-2010, 03:45 PM

Looks like the green line issue I had. A firmware update fixed mine. Which version of firmware are you running?

Asudef · 06-14-2010, 05:59 PM

So you think this would be a result of the firmware then?

Mine is probably 1.00. The guy I bought it from barely touched the camera.

I was hesitant since I haven't read about the new firmware fixes. I'll probably do that after I read a bit more and see if it fixes it.

r0ckstarr · 06-14-2010, 09:43 PM

Originally posted by Asudef

So you think this would be a result of the firmware then?

Mine is probably 1.00. The guy I bought it from barely touched the camera.

I was hesitant since I haven't read about the new firmware fixes. I'll probably do that after I read a bit more and see if it fixes it.

Read this thread for more info:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/65879-k7-busted-se...tion-body.html

**jeffshaddix** · 08-03-2010, 08:42 PM

Hey OP, did you send your camera in and get the sensor replaced? I've got the same issue on my K-7.

02-16-2010, 02:39 AM	#21
Norman Forum Member Join Date: Feb 2010 Location: Stockholm Posts: 54 Original Poster	Originally posted by Jadran You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7 But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar. Hm, except in my case I dont have that prominent green line and my banding is more purpleish. So is this something I should worry about or is it normal? This pic is ISO100 (brought up the levels by alot digitally) as the other. Edit: Correction, I can see a slight tint of the band at ISO3200 when I take a shot with lens cover on. But it's easily hidden by the normal ISO noise, and even more so when bringing levels up. Attached Images Last edited by Norman; 02-16-2010 at 02:52 AM.

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02-15-2010, 04:33 PM	#16
zxaar Veteran Member Join Date: Jul 2009 Location: kobe/japan Posts: 510	my sony r1 had true liveview and when i shot with it, 95% of time liveview was on. So sensor heating up and showing banding is not much of an issue. But sensor heat do contribute to noise (my subjective opinion). interesting question would be what other pentax cameras show banding. Because my suspect is the way sony sensors are implemented they might not show banding.

02-15-2010, 05:07 PM	#17
Jadran Senior Member Join Date: Sep 2009 Location: Zagreb Photos: Albums Posts: 105	Originally posted by zxaar my sony r1 had true liveview and when i shot with it, 95% of time liveview was on. So sensor heating up and showing banding is not much of an issue. But sensor heat do contribute to noise (my subjective opinion). interesting question would be what other pentax cameras show banding. Because my suspect is the way sony sensors are implemented they might not show banding. My guess is that there is varying tolerance to the heat that the K-7 sensors have (quality control?). Could be also that only few are affected, it's hard to say. As I said, the one that I have now has no problems with banding at all, no meter of LV use, outside temperature, ISO, or any other conditions. But the first one was catastrophe, which was eventually diagnosed by Pentax Service as faulty sensor.

02-15-2010, 05:29 PM	#18
zxaar Veteran Member Join Date: Jul 2009 Location: kobe/japan Posts: 510	Originally posted by Jadran My guess is that there is varying tolerance to the heat that the K-7 sensors have (quality control?). Could be also that only few are affected, it's hard to say. As I said, the one that I have now has no problems with banding at all, no meter of LV use, outside temperature, ISO, or any other conditions. But the first one was catastrophe, which was eventually diagnosed by Pentax Service as faulty sensor. i was not aware that it could vary camera to camera. Thanks for your posting , it might be helpful to others. on another forum i frequently visit, there was someone wondering about banding issue with canon 7d. she did send her files to canon and canon refused to acknowledge problem. i will advice her to try to change her camera body, she might get rid of banding.

02-15-2010, 06:05 PM	#19
asdf Veteran Member Join Date: Jan 2009 Location: Canada Posts: 1,252	Originally posted by zxaar i was not aware that it could vary camera to camera. Thanks for your posting , it might be helpful to others. on another forum i frequently visit, there was someone wondering about banding issue with canon 7d. she did send her files to canon and canon refused to acknowledge problem. i will advice her to try to change her camera body, she might get rid of banding. The pattern may vary, but I suspect the other poster is mistaken. There is no image to back up the claim. It's easy to reproduce the pattern (or show it's not there): just slightly overexpose a gray or black area at the highest ISO setting. To avoid this pattern noise, Sony's latest sensors have an A/D converter per column (or so I read). EDIT: "At the same time, however, the following problems occur in conventional CMOS sensors. Although the fixed pattern noise between pixels can be removed by the CDS circuits located at each column, a vertical form of fixed pattern noise oc- curs due to differences between the CDS circuits themselves. Also a capacitor with a size larger than a certain value is required in the CDS circuit to record and hold the post-CDS signal, and this results in an increase in the area of this circuit. Furthermore, the recorded and stored analog signals are easily influenced by switching noise in the high-frequency band due to the horizon- tal transfer operations. To resolve these problems, Sony adopted the column-parallel A/D conversion tech- nique. (See figure 2.) " http://www.sony.net/Products/SC-HP/cx_news/vol47/pdf/featuring47.pdf Last edited by asdf; 02-15-2010 at 06:20 PM.

02-16-2010, 02:02 AM	#20
Jadran Senior Member Join Date: Sep 2009 Location: Zagreb Photos: Albums Posts: 105	Originally posted by asdf The pattern may vary, but I suspect the other poster is mistaken. There is no image to back up the claim. It's easy to reproduce the pattern (or show it's not there): just slightly overexpose a gray or black area at the highest ISO setting. To avoid this pattern noise, Sony's latest sensors have an A/D converter per column (or so I read). ] You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7 But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar.

02-16-2010, 02:53 AM	#22
Jadran Senior Member Join Date: Sep 2009 Location: Zagreb Photos: Albums Posts: 105	Yes, in my case banding was much much worse, though in cases when sensor didn't heat up (some first dozen shoots) it was withouth lines and much more simillar to your case. I'm not clever here. If you think that this banding doesn't affect the most of you shoots, then maybe you shouldn't be worried. Or, maybe you could conntact Pentax Service, send them samples of banding and ask for assistance. In this case I had very good experinece with Pentax representative in Croatia and Pentax Europe HQ Service in Paris, France. They were willing to help.

02-16-2010, 03:10 AM	#23
asdf Veteran Member Join Date: Jan 2009 Location: Canada Posts: 1,252	Originally posted by Jadran You re right about this, but what I see from OP's sample is vertical band, and if it shows at the same place it doesn't look quite like pattern noise. Here is the crop from my faulty sensor K-7 But, it was really prominent on every shoot. There is no way I can't reproduce such banding with the second K-7. I'm not claiming that OP has same problem, but banding is just suspiciously similar. I see now. That's definitely not noise, but a faulty sensor. The pattern noise I was thinking about were "bands" of slightly different luminance. This kind of thing seems to appear on every camera, except the latest and greatest. Just google "k20d banding" or "k10d banding".

02-16-2010, 05:12 AM	#24
Norman Forum Member Join Date: Feb 2010 Location: Stockholm Posts: 54 Original Poster	It doesnt affect most of my shots, but still annoys me to know it is there. Makes me see things (which probably arent there) but feels like there's a tint of purple/pink at that area when I develop my shots. Ill probably buy a k-X meanwhile and send my k-7 for service here in sweden. Got to find my proof of purchase now from fry's. (Camera bought in the US, but I live in Sweden)

02-16-2010, 11:22 AM	#25
cyy47 Senior Member Join Date: Jun 2009 Location: Boston, MA Photos: Gallery \| Albums Posts: 157	I had the same issue, but only at higher iso. K7 banding I sent it back and am anxiously waiting for the replacement.

06-14-2010, 03:36 PM	#26
Asudef Forum Member Join Date: Feb 2010 Location: San Francisco Posts: 79	I just got a K7 used and took some shots last night and discovered this issue. It's pretty noticeable and there seem to be other unrelated issues I'm trying to test out (softness &/or front/back focusing), considering it's their best camera, this isn't acceptable. I bought a K20 used and that thing never had any issues. I haven't updated the firmware yet, would that make a difference? The seller says he would help with the warranty process since it was local and it's only been a day I'd like to do something about it ASAP. Is this anything to be worried about? Shot at ISO100 w/ the WR kit lens in low light, f/5.6 @ 1/2s.

06-14-2010, 03:45 PM	#27
r0ckstarr Veteran Member Join Date: Sep 2009 Location: Texas Photos: Gallery Posts: 3,507	Looks like the green line issue I had. A firmware update fixed mine. Which version of firmware are you running?

06-14-2010, 05:59 PM	#28
Asudef Forum Member Join Date: Feb 2010 Location: San Francisco Posts: 79	So you think this would be a result of the firmware then? Mine is probably 1.00. The guy I bought it from barely touched the camera. I was hesitant since I haven't read about the new firmware fixes. I'll probably do that after I read a bit more and see if it fixes it.

06-14-2010, 09:43 PM	#29
r0ckstarr Veteran Member Join Date: Sep 2009 Location: Texas Photos: Gallery Posts: 3,507	Originally posted by Asudef So you think this would be a result of the firmware then? Mine is probably 1.00. The guy I bought it from barely touched the camera. I was hesitant since I haven't read about the new firmware fixes. I'll probably do that after I read a bit more and see if it fixes it. Read this thread for more info: https://www.pentaxforums.com/forums/pentax-dslr-discussion/65879-k7-busted-se...tion-body.html

08-03-2010, 08:42 PM	#30
jeffshaddix Site Supporter Join Date: Jun 2010 Location: Colorado Posts: 1,473	Hey OP, did you send your camera in and get the sensor replaced? I've got the same issue on my K-7.