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10-12-2018, 07:47 PM   #31
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QuoteOriginally posted by lazarustx Quote
Thanks Mark for helping me out.

This is a bit frustrating since even the extended warranty folks agree that I'm going to have to find a solid recreate and talk to the Pentax support folks before they'll consider any type of repairs.
I'll see what I can do about the recreate, but its random nature might have me pulling my hair out...

Regards,
Rodney
That is, indeed, frustrating. But, I would suggest that the evidence you have posted here does not seem that random. If you take a (good) SD card, and format that in camera, how long does it work, do you think, before the problem occurs?

10-12-2018, 08:13 PM   #32
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Just a random thought - how long after you snap a photo before you flip the power button off (if you 're doing that)? Most cameras will go ahead and write to the SD card even though the power has been turned off, but any chance there could be something going on when the power switch is flipped before the SD card has been completely written and the file has been closed?
10-14-2018, 03:22 PM   #33
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Corrupt Images: Any last suggestions before I send the K1 in for repairs?

Here's what I've decided to try:
1. Repartitioned the SD Cards and did an in Camera format.
2. Setup the camera for Interval Continuous shooting while sitting on my desk.

3. Set Backup Mode so we write images to Slot 1 and Slot 2.

4. Let the camera take 500 shots.
5. Copied Images from cards to HD, then did an import from the HD.

6. Image 306 is the first image to show up as bad.


A few thoughts:

A. 500 shots of a stationary object(my desk) with out any intervention means that I've captured similar images outside of time and lighting. Its party cloudy and I'm facing a south window.
B. So, Using Beyond Compare, I can see that Slot 1 and Slot 2 images are identical. Compared that with the Imported image in LR and its the same.

C. That's a pretty good argument for it being camera based...

NOTE: I did take a look at the prior image and did a compare of the corrupt image. I see that the time stamp is off by milliseconds. That's the first change. However, that's where my reading raw image skills fall apart. Anyone know how to take a look at these files to see's different?

Again, I'm just looking for patterns here that I might use to coax the Pentax Service folks to look at.

Thanks!

Last edited by lazarustx; 10-14-2018 at 09:55 PM.
10-15-2018, 02:30 PM   #34
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QuoteOriginally posted by lazarustx Quote
Here's what I've decided to try:
1. Repartitioned the SD Cards and did an in Camera format.
2. Setup the camera for Interval Continuous shooting while sitting on my desk.

3. Set Backup Mode so we write images to Slot 1 and Slot 2.

4. Let the camera take 500 shots.
5. Copied Images from cards to HD, then did an import from the HD.

6. Image 306 is the first image to show up as bad.


A few thoughts:

A. 500 shots of a stationary object(my desk) with out any intervention means that I've captured similar images outside of time and lighting. Its party cloudy and I'm facing a south window.
B. So, Using Beyond Compare, I can see that Slot 1 and Slot 2 images are identical. Compared that with the Imported image in LR and its the same.

C. That's a pretty good argument for it being camera based...

NOTE: I did take a look at the prior image and did a compare of the corrupt image. I see that the time stamp is off by milliseconds. That's the first change. However, that's where my reading raw image skills fall apart. Anyone know how to take a look at these files to see's different?

Again, I'm just looking for patterns here that I might use to coax the Pentax Service folks to look at.

Thanks!
That sounds like a pretty decent test. So, are you saying image 306 is bad on both SD cards? If so, that would be a compelling reason to suspect the camera, I think. Any other bad shots on either / both cards?

10-16-2018, 03:55 AM   #35
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Here's a couple of thoughts...

You say this has been happening over the last couple of years, the EXIFs show a K-1 II, and you said the camera has been upgraded. That sounds as if there's a very intermittent camera fault, somewhere that didn't get touched in the upgrade. To me, intermittent would strongly suggest hardware rather than firmware, which would also fit with the fact that the identical corrupt image ends up on two independent SD cards. It's just barely possible that there's a particular combination of image data that screws up the lossless compression, so it's worth checking that you have the latest firmware; you never know, "Improved stability for general performance" may be just what you're after.

Is there anything else you can do with the PEF/DNG in DCU which causes the corruption to show up on-screen before you do a "save as"? It sounds very weird that a corrupt image would only manifest itself at the point where you're saving it. In post #23 you say the corruption doesn't show in DCU either on-screen or if you export a JPEG - that suggests the original RAW isn't terminally corrupt, just subject to misinterpretation in very specific circumstances.

Finally, it might be worth repeating your 500-shot test, with the following changes: use RAW+, if the JPEG is also corrupt then the data being captured is wrong, and it's a hardware problem; also, use auto-bracketing with 2 images and minimum (0.3EV) exposure change, use HDR with ±1EV steps so if it's "corner case" image data then one of the pair only one of the three sub-images is likely to be corrupted (turns out you can't interval shoot and bracket at the same time, which is clearly a Wrong Thing...).

Hope this helps

Last edited by h4yn0nnym0u5e; 10-16-2018 at 07:42 AM.
10-16-2018, 02:21 PM   #36
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QuoteOriginally posted by MarkJerling Quote
That sounds like a pretty decent test. So, are you saying image 306 is bad on both SD cards? If so, that would be a compelling reason to suspect the camera, I think. Any other bad shots on either / both cards?
Yes, it appears that both cards have the same image.
No more bad shots on this batch of images. I need to setup another round of images to check.

Regards,
Rodney
10-16-2018, 02:41 PM   #37
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QuoteOriginally posted by lazarustx Quote
Yes, it appears that both cards have the same image.
No more bad shots on this batch of images. I need to setup another round of images to check.

Regards,
Rodney
How very peculiar. But, I'd say it's clear you have a camera problem.

10-16-2018, 06:47 PM   #38
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QuoteOriginally posted by h4yn0nnym0u5e Quote
Here's a couple of thoughts...

You say this has been happening over the last couple of years, the EXIFs show a K-1 II, and you said the camera has been upgraded. That sounds as if there's a very intermittent camera fault, somewhere that didn't get touched in the upgrade. To me, intermittent would strongly suggest hardware rather than firmware, which would also fit with the fact that the identical corrupt image ends up on two independent SD cards. It's just barely possible that there's a particular combination of image data that screws up the lossless compression, so it's worth checking that you have the latest firmware; you never know, "Improved stability for general performance" may be just what you're after.

Is there anything else you can do with the PEF/DNG in DCU which causes the corruption to show up on-screen before you do a "save as"? It sounds very weird that a corrupt image would only manifest itself at the point where you're saving it. In post #23 you say the corruption doesn't show in DCU either on-screen or if you export a JPEG - that suggests the original RAW isn't terminally corrupt, just subject to misinterpretation in very specific circumstances.

Finally, it might be worth repeating your 500-shot test, with the following changes: use RAW+, if the JPEG is also corrupt then the data being captured is wrong, and it's a hardware problem; also, use auto-bracketing with 2 images and minimum (0.3EV) exposure change, use HDR with ±1EV steps so if it's "corner case" image data then one of the pair only one of the three sub-images is likely to be corrupted (turns out you can't interval shoot and bracket at the same time, which is clearly a Wrong Thing...).

Hope this helps
Hello,
I've reflashed the Firmware after reading your post. I'll keep my eyes open for any future Firmware updates.

I'll work on your questions about the DCU. I'll double check my facts regarding the JPGs, but that seems to be correct.

I'll redo my test with your suggested settings. . Although I'm not sure what "corner case" image data is.

Thanks again.

Regards,
Rodney
10-16-2018, 09:37 PM   #39
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QuoteOriginally posted by MarkJerling Quote
How very peculiar. But, I'd say it's clear you have a camera problem.
Yep, now the chore is to find a method of recreating this for either Precision or Pentax. I have no way of knowing how to reach Pentax/Ricoh support. I suppose I'd need to reach out to Precision folks.

Regards,
Rodney
10-17-2018, 02:36 AM - 1 Like   #40
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QuoteOriginally posted by lazarustx Quote
Yep, now the chore is to find a method of recreating this for either Precision or Pentax. I have no way of knowing how to reach Pentax/Ricoh support. I suppose I'd need to reach out to Precision folks.

Regards,
Rodney
Try Precision first - probably your best bet. If not, PM Adam - he may have a suggestion as to who to contact.
10-18-2018, 08:37 AM   #41
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@h4yn0nnym0u5e Using your test, I ran through 500 images with no corruption. I set the camera up for another round of images. I'll check those today and see if anything shows up as corrupt. I'm not really sure how this helps to narrow a hardware/vs software issue. Could you explain this a bit more?


Regards,
Rodney
10-19-2018, 11:54 AM   #42
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@h4yn0nnym0u5e, another 500 images taken without any visibly corrupt files. Hmmm....I'll set the camera back to its normal state and use it this weekend. I'll report back.


What I would like to know is what made you think that this process would affect my images?

Thanks for your feedback!

REgardsi
Rodney
10-19-2018, 01:06 PM - 2 Likes   #43
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QuoteOriginally posted by lazarustx Quote
@h4yn0nnym0u5e Using your test, I ran through 500 images with no corruption. I set the camera up for another round of images. I'll check those today and see if anything shows up as corrupt. I'm not really sure how this helps to narrow a hardware/vs software issue. Could you explain this a bit more?
Sure, no problem.

My simplistic understanding of how you get light onto an SD card is that the sensor creates 36 million voltages, one for each pixel (18M green, 9M each red and blue); each voltage in turn is then converted to a 14-bit number and stored in RAM; and these 14-bit numbers are then compressed and stored on the SD card, either as a DNG (lossless compression) or JPEG (lossy compression). There's lots of steps omitted here, no doubt, but it'll do.

We can probably assume the sensor is broadly OK, or every image would be corrupt. Equally, your post #18 suggests that the SD cards are not to blame, as you get identical corruption when writing to two cards.

Getting the voltages off the sensor could be the issue; if there's a loose "red" wire then it could be fine at the start of the conversion process, then lose contact halfway through the conversion process, leaving you with a cyan cast over half the picture. It could equally come back into contact, so you get the cast for a tenth, or a line - either way, it's a hardware problem, the RAM copy is corrupt, and nothing will bring it back. In this case, both the JPEG and DNG on your SD card (if you write RAW+) will show near-identical corruption. A repair might be to replace the sensor or some other part.

Now what happens if the RAM itself is flaky (still a hardware problem)? If it's the area used for the uncompressed image then a major fault would give you many corrupt images, and a minor one probably some coloured dots, like those you get anyway from the sensor not being 100% perfect. So, either really noticeable, or hardly visible. However, what if the compressed images are stored in flaky RAM prior to writing to SD? Depending on the compression algorithm and the image content, a tiny RAM fault could result in anything from an imperceptible error all the way up to a majorly corrupt image. Such a fault could be a permanently "stuck" bit or one that just occasionally loses its memory, including due to radioactivity in the chip itself - that's really random... In this case you might expect only one of the JPEG or DNG to be corrupt, because they were created from a valid uncompressed image, either in turn or to two different areas of RAM; they could both be corrupt, but you'd expect the corruptions to be different because of the different compression algorithms. To repair this would require replacing the camera's "motherboard".

Then there's the "corner case" that I failed to explain. It can occasionally happen that an algorithm (compression, in this case) can be "upset" by a particular sequence of data, especially if it hasn't been rigorously tested. Some encodings, for example, don't allow a run of more than 5 zero values; if you have 9 to encode, you have to do 5 zeroes, then a 1 (which is discarded by the decoder), then the last 4 zeroes. That's hard to get wrong in either the encoder or decoder, but the lossless coding used for DNGs looks to be a lot more complex, and it's barely possible that Ricoh have, or had, a bug in their code which is only apparent for some patterns of image data. I'm sure they're constantly tweaking it, because it'll be part of the engineering going into getting the fastest possible buffer clear times. In this case you'd again expect only one of the DNG and JPEG to be corrupt, as the compression algorithms are radically different. A firmware update might fix the problem.

The corner case argument also applies to LR and DCU (and any other PP software you might try). Here, I don't know if there's any commonality - it could be everyone uses the same library code, and that has a bug in it! But your statement that DCU can actually open a "corrupt" DNG and show it uncorrupted at full resolution (i.e. we're not being confused by the embedded JPEG) is a real head-scratcher. Why on earth would it then decide to show it corrupted when you do a Save as...? And why not if you export a JPEG? That just strikes me as bonkers, though it does also suggest the image can't be truly corrupt, just slightly weird in a way that affects all known PP software. [On going back through this thread I noticed that @frankoz has seen this problem too, using C1 and RT, two versions of Windows and Linux.] In this case, sending your camera for repair won't help.

There you go, a bit wordy but I hope it makes some sort of sense.

Cheers

Jonathan
10-19-2018, 01:11 PM - 1 Like   #44
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QuoteOriginally posted by lazarustx Quote
@h4yn0nnym0u5e, another 500 images taken without any visibly corrupt files. Hmmm....I'll set the camera back to its normal state and use it this weekend. I'll report back.


What I would like to know is what made you think that this process would affect my images?

Thanks for your feedback!

REgardsi
Rodney
Did you use RAW+ for these? I didn't expect it to affect the images, just maybe give a clue as the the root cause (see the previous loquacious post!). But maybe it's worked as a magic fix, as long as you can live with the slower writes... You might want to use the "abnormal state" this weekend for any especially important images! Good luck.

Cheers

Jonathan
10-19-2018, 05:05 PM   #45
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QuoteOriginally posted by frankoz Quote
Guys,

I have owned Pentax DSLRs from the K10D to the K1 and have never had a problem. However I have also owned the Ricoh GR and currently the GRII and both have produced these corrupt images on what appears to be a random basis.

I have attempted to find a fix in the past through the Ricoh Forum, without success and haven't been able to get much traction here.


I commonly save images to the same SD (GR only has one) as both DNG and JPG. On occasions where I find a corrupt image, it seems to be the DNG file only - the JPG is my fall back.

I have historically used LR but have also tried Capture One , DxO and RawTherapee as editors as well as a freeware app called Irfanview. Each can read DNG files, occasionally (not often) the fault shows in one and not the other, however predominantly, the same fault appears apparently regardless of software. Frustratingly, the correct image has often shown in preview mode before the banding and colour corruption overlay as the image is chosen for editing.

For the above reasons, I don't think it is your camera, leastwise the hardware, it may be the firmware or perhaps the brand or type of SD card. I haven't been able to check or trial them.


Anyway, that is my experience and I probably lose maybe 1% of my images on the Ricoh. Murphy's Law, it always seems to be that perfect shot too lol.

A solution would be wonderful.

Here is a screenshot of a recent corrupt image https://www.pentaxforums.com/forums/members/39261-frankoz/albums/12778-misc/picture120158.jpg


Rgds,
John
John,
I'm re-reading this thread and noticed that I had overlooked your update. I appreciate the feedback. I'm going to give the SD Card formatter a try as well as pick up a brand of SD card that I don't own. I'll continue to monitor my camera. I'll also stick to RAW+ for the time being. I can use my JPG image as backup. Thanks!
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