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06-20-2007, 05:53 PM   #1
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Strange problems with my K10D

I've had my K10D since November and I'm trying to work through some problems that keep cropping up with it. Now I will readily admit I'm most likely the source of them as I realized once I used it for awhile that it way too much camera for me. I had a Nikon D50 before this, and sold it for the K10D's anti-shake as my hands are none too steady. I'm trying to work my way up the level needed to utilize this camera.

My most recent issue is when I was taking pictures of my K1000, purple "mazes" appeared at two areas, one across the shutter button barrel, and across the "Pentax" label on the front of the camera. Now I shot these in RAW, and using Raw Photo Processor there was no purple mazes, but with ACR 4.1 and Pentax Photo Laboratory, there was. Here is an JPEG example of it, saved from CS3:

https://www.pentaxforums.com/gallery/index.php?n=2448

This example of (what I think) is excess noise. ISO 800 with a flash, I cropped this to show the pattern noise in the background of this picture.

https://www.pentaxforums.com/gallery/index.php?n=2449

Now I know these are crops and could be considered pixel peeping, but the purple mazes were apparent to me without zooming into the message. I also have an example of pattern noise in a ISO 400 shot if I can dig it up. With this said, is it me? I can supply the EXIF information it would make the determination easier.

06-20-2007, 07:39 PM   #2
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The "purple mazes" appear to be chromatic abberations (or purple fringing). It's caused partly by the lens, at high contrast areas borders (often on the edges of tree branches that are back lit). It can be fixed in post-processing when using RAW. Not sure about JPEG.

As for the pattern noise, i'm unclear which you are referring to - the cabinet area, or the wall. The cabinet seems to have some sort of moire effect - usually when the anti-aliasing filter on the camera is not strong enough. There really is no fix for this in post-processing, and it does not occur very often in my experience. (actually, I have not had the problem at all, but it requires very specific circumstances).
06-20-2007, 08:43 PM   #3
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I got this maze effect in one series of shots of a model where the maze was in her eyes. Turned out she had contacts in. The next series using the same equipment and similar settings but with different model didn't show them.

I have gotten odd patterns like that (not VPN) in digital shots from several different cameras. Sometimes it turned out there was a pattern in the scene that I just didn't see with my naked eye. Shot through some glass on a cruise ship last fall and got this weird pattern on the glass. Turned out that I could see it through my wife's sunglasses too.

I don't think your camera has a problem that you need to worry about. If the maze shows up in the odd photo simply process it in the app that doesn't show it. No biggie, seems to me. For one thing, if it shows up in some apps and not others it is the app, not the camera.
06-20-2007, 09:02 PM   #4
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QuoteOriginally posted by Narcoleptic Quote
I've had my K10D since November and I'm trying to work through some problems that keep cropping up with it. Now I will readily admit I'm most likely the source of them as I realized once I used it for awhile that it way too much camera for me. I had a Nikon D50 before this, and sold it for the K10D's anti-shake as my hands are none too steady. I'm trying to work my way up the level needed to utilize this camera.

My most recent issue is when I was taking pictures of my K1000, purple "mazes" appeared at two areas, one across the shutter button barrel, and across the "Pentax" label on the front of the camera. Now I shot these in RAW, and using Raw Photo Processor there was no purple mazes, but with ACR 4.1 and Pentax Photo Laboratory, there was. Here is an JPEG example of it, saved from CS3:

https://www.pentaxforums.com/gallery/index.php?n=2448

This example of (what I think) is excess noise. ISO 800 with a flash, I cropped this to show the pattern noise in the background of this picture.

https://www.pentaxforums.com/gallery/index.php?n=2449

Now I know these are crops and could be considered pixel peeping, but the purple mazes were apparent to me without zooming into the message. I also have an example of pattern noise in a ISO 400 shot if I can dig it up. With this said, is it me? I can supply the EXIF information it would make the determination easier.
I have sent my K10D in for warranty repair due to a pattern like your second example. I don't know yet if Pentax will accept it as a fault, but my K10D is incapable of producing the smooth tonal graduations that my *istD did, so I consider it a fault. As for your first example I'd also classify that as unacceptable. Since Pentax' own software shows the pattern, it is a Pentax issue, either the camera or the software, they can debate that with themselves. My vote is that the camera is at fault since you get the same result with two different applications. Your third application, Raw Photo Processor, may luckily be able to process and remove the pattern as a part of its noise reduction.

06-20-2007, 09:07 PM   #5
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QuoteOriginally posted by Narcoleptic Quote
I've had my K10D since November and I'm trying to work through some problems that keep cropping up with it. Now I will readily admit I'm most likely the source of them as I realized once I used it for awhile that it way too much camera for me. I had a Nikon D50 before this, and sold it for the K10D's anti-shake as my hands are none too steady. I'm trying to work my way up the level needed to utilize this camera.

My most recent issue is when I was taking pictures of my K1000, purple "mazes" appeared at two areas, one across the shutter button barrel, and across the "Pentax" label on the front of the camera. Now I shot these in RAW, and using Raw Photo Processor there was no purple mazes, but with ACR 4.1 and Pentax Photo Laboratory, there was. Here is an JPEG example of it, saved from CS3:

https://www.pentaxforums.com/gallery/index.php?n=2448

Another thought, could the maze be jpeg artifacts? Try not to convert to jpeg but save as tif, take a look at it and let us know.
06-20-2007, 10:57 PM   #6
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Just like the *ist D, the K10D (sensor?) is more susceptible to purple fringing than some other DSLRs like the K100D. Of course, the problem is that the lens does exhibit certain degree of CAs in the first place.

You can use some software to elliminate this undesirable effect somehow. But primitively, it is there!

QuoteOriginally posted by Narcoleptic Quote
I've had my K10D since November and I'm trying to work through some problems that keep cropping up with it. Now I will readily admit I'm most likely the source of them as I realized once I used it for awhile that it way too much camera for me. I had a Nikon D50 before this, and sold it for the K10D's anti-shake as my hands are none too steady. I'm trying to work my way up the level needed to utilize this camera.

My most recent issue is when I was taking pictures of my K1000, purple "mazes" appeared at two areas, one across the shutter button barrel, and across the "Pentax" label on the front of the camera. Now I shot these in RAW, and using Raw Photo Processor there was no purple mazes, but with ACR 4.1 and Pentax Photo Laboratory, there was. Here is an JPEG example of it, saved from CS3:

https://www.pentaxforums.com/gallery/index.php?n=2448

This example of (what I think) is excess noise. ISO 800 with a flash, I cropped this to show the pattern noise in the background of this picture.

https://www.pentaxforums.com/gallery/index.php?n=2449

Now I know these are crops and could be considered pixel peeping, but the purple mazes were apparent to me without zooming into the message. I also have an example of pattern noise in a ISO 400 shot if I can dig it up. With this said, is it me? I can supply the EXIF information it would make the determination easier.
06-21-2007, 10:56 AM   #7
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QuoteOriginally posted by MikeH Quote
The "purple mazes" appear to be chromatic abberations (or purple fringing). It's caused partly by the lens, at high contrast areas borders (often on the edges of tree branches that are back lit). It can be fixed in post-processing when using RAW. Not sure about JPEG.
I wasn't aware that CA could appear like this, I thought it was only a problem in situations like the tree branch that you describe.

QuoteQuote:
As for the pattern noise, i'm unclear which you are referring to - the cabinet area, or the wall. The cabinet seems to have some sort of moire effect - usually when the anti-aliasing filter on the camera is not strong enough. There really is no fix for this in post-processing, and it does not occur very often in my experience. (actually, I have not had the problem at all, but it requires very specific circumstances).
More the cabinet area, but I was also surprised at the amount of general noise in that shot. It seems hit or miss with me, some ISO 800 shots will turn out fine, some like this. This is the first time I've seen the moire effect, but I have had some vertical pattern noise appear in some of my shots. I never use ISO 1600, its happened at ISO 800 mostly.

QuoteOriginally posted by Ole Quote
I have sent my K10D in for warranty repair due to a pattern like your second example. I don't know yet if Pentax will accept it as a fault, but my K10D is incapable of producing the smooth tonal graduations that my *istD did, so I consider it a fault. As for your first example I'd also classify that as unacceptable. Since Pentax' own software shows the pattern, it is a Pentax issue, either the camera or the software, they can debate that with themselves. My vote is that the camera is at fault since you get the same result with two different applications. Your third application, Raw Photo Processor, may luckily be able to process and remove the pattern as a part of its noise reduction.
Part of the reason for this thread was to help my decision to send the camera in or not to be checked by Pentax. Mine is a early production example, and I've had some other issues crop up but I've never been sure if it was just an anomaly, or something wrong with the camera itself. It is difficult to judge with my limited experience.

QuoteOriginally posted by Ole Quote
Another thought, could the maze be jpeg artifacts? Try not to convert to jpeg but save as tif, take a look at it and let us know.
No, the mazes appear in the RAW (shot as DNG). I was just shooting RAW at the time, no JPEG. This particular image was converted by ACR 4.1 and saved by CS3 as a 100% quality JPEG. If anything they're more apparent in the RAW shots. When I was making this example I was worried that JPEG compression would mask the mazes if turned down the quality.
06-24-2007, 08:10 PM   #8
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I took pictures at a wedding and all the images seem to me to be unusable. All were with a FA 50mm f/1.4 lens, and the noise (all at ISO 800, 1/60, f/4-4.5, flash) is heavy. Black tuxedos aren't really black, they just have a pattern across the fabric. It looks somewhat the moire pattern in examples in the first post, but seems to repeat itself two or three times across the frame. I think I may send my camera in to have Pentax take a look at it. I've run into a wall in respect of my ability to determine if it is me or the camera itself. But now I have about 101 examples of my problem.

06-25-2007, 09:51 AM   #9
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Well the mazes are bayer pattern artifacts. They can happen with any digital camera that uses a bayer pattern, which is most of them, and is not a defect unless they are cropping up where they should not be.

They come up because in some situations the mathematical formula to determine edges can have more than one valid result. I suspect you got them in that pic because in the particular area you have chromatic abberation due to the high contrast transition from the black pentax to the reflective textured metal surface, and parts of the texturing that are reflecting more light are clipping. The net reuslt is the bayer pattern filter algorithm doesn't ahe a lot of data to work with to determine edges. If you took the smae picture with a smaller apeture or a faster shutter, or lighting from a different angle so the reflected light wasn't as intense, you wouldn't have gotten them.

As for that weird herringbone pattern noise, I have not seen that fron my camera at all. Either using ACR or jpegs right out of the camera.
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