[Al_Kahollick]

Okay, today the problem occurred again, here are my findings:
Took 46 photos today, and 2 of them were corrupt, 23rd and 29th file.

The corruption does not show up on camera screen, even after using the card in the card reader and copying images on hard drive.
It does not show up on camera JPEG, only on imported RAW DNG.
It does show up on both cards.

I tried different ways of importing the files, and here is where it gets weird.
If I copy the files from SD card to my computer/external hard drive, and import them into Lightroom from there, the problem shows up in develop and also on exported jpeg.
If I import the files to Lightroom directly from the SD card or via USB connected to the camera, the problem shows itself during develop process preview for about 2 seconds, then it disappears and shows whole image correctly, and exported jpeg is perfectly OK as well.


Seems like there is some problem in the writing process in-camera, but there still is whole data available in the card that gets lost when files are copied.

Sounds like maybe your computer / video card may be the culprit. Perhaps it's struggling with the extra data in the RAW file or maybe the card is overheating. Does the same thing happen when you try to open them directly from the SD card without importing them into an editing program?
Have you tried opening them on a different computer?


It seems to me that the data is there, but for some reason your computer isn't displaying all of it. Good news is, perhaps it's not the camera , bad news, may need a new computer or at least video card .

[rRnt]

If it was a video card, don't you think that it would not stick to specific images but different ones every time? It also does not happen every time I go out shooting and does not seem to be depending on how many images I have shot. Today one image showed 50% corruption, the other, and the ones before that have shown about third of the image covered with stripes. I have not tried another computer.

Ok, I installed the Adobe DNG codec, and opened the known corrupt raw files in Windows Photo Viewer:
When opening file on the SD card in my laptop's card reader - no corruption shown.
When opening file copied to computer after I installed the codec - no corruption shown. Corruption does not show up in Lightroom after importing it either.
When opening file copied to hard drive before I installed the codec (and that had been imported to Lightroom also) - corruption is present, but only after the image is fully loaded, during loading it displays low-resolution image without corruption.

At least I now know, that if (when) I get the issue again, I can use the image on the card and import it directly from there. It appears that the DNG codec might solve the problem when it reappears, although I am not a fan of it (it takes a lot of time to generate thumbnails for all the DNG files and even longer to open and view them).

[MadMathMind]

Some terminology for you: CODEC stands for coder/decoder and is only used for audio/video files. The big difference is that since JPEG only stores a single frame, it doesn't have to code the signal to save space--there's nothing to compare it with. A video codec, for instance, saves space by figuring out only which pixels change from frame to frame and storing those changes. How you go about writing that information is a part of the encoding process. JPEG is a bit more simplistic: you work in frequency space (take discrete cosine transformation) and figure out which information is redundant or least necessary. By not storing a bunch of zeros for information not in the file, you can save a lot of space. To produce the image, merely invert the transform and you're all set. It's rather different from coding and decoding because you're just representing the data in a different way. It's like taking text and storing it in Chinese and English. The content is preserved in both cases but some people will need a translator to understand it.

Consider the difference in size between an all black image stored in TIFF and JPEG format. I did a little test: for a 1920x1080 image, JPEG produces a file of 163KB and the TIFF is over 6MB. For a 1920x1080 image file with something interesting in it, the JPEG save was 1 MB and the TIFF was over 6 MB--it was SMALLER than the all black image! The content itself is pretty irrelevant for an (uncompressed) TIFF file because it has to store information about every pixel, even if all that information is zero.

DNG is not a compression scheme, codec, or anything like that. It is a container. Technically, any file extension is a container (JPEG, AVI, MKV, etc.) but for image files, there's limited compression schemes that container can support (e.g., LZW or ZIP compression in TIFF files). RAW files contain sensor data. DNG just provides a place to put that information. Without the original camera specification on how that data should be arranged, the data is useless, which makes it different from normal image files, which are camera independent. This is why you open DNG files with a RAW converter or engine, software that knows how to interpret the data and produce a working image from it. DNG files really are processed and incapable of being "viewed" as JPEG files are.

[Al_Kahollick]

If it was a video card, don't you think that it would not stick to specific images but different ones every time? It also does not happen every time I go out shooting and does not seem to be depending on how many images I have shot. Today one image showed 50% corruption, the other, and the ones before that have shown about third of the image covered with stripes. I have not tried another computer.

Ok, I installed the Adobe DNG codec, and opened the known corrupt raw files in Windows Photo Viewer:
When opening file on the SD card in my laptop's card reader - no corruption shown.
When opening file copied to computer after I installed the codec - no corruption shown. Corruption does not show up in Lightroom after importing it either.
When opening file copied to hard drive before I installed the codec (and that had been imported to Lightroom also) - corruption is present, but only after the image is fully loaded, during loading it displays low-resolution image without corruption.

At least I now know, that if (when) I get the issue again, I can use the image on the card and import it directly from there. It appears that the DNG codec might solve the problem when it reappears, although I am not a fan of it (it takes a lot of time to generate thumbnails for all the DNG files and even longer to open and view them).

So it appears the trouble lies in your computer then........... you're welcome!

[rRnt]

Some terminology for you: CODEC stands for coder/decoder and is only used for audio/video files.

Sorry, but what does all that fancy terminology got to do with the problem at hand? Kind of off-topic. Anyway, I was not the one who named it a "codec" - Adobe calls it that, so why would I call it any different?:
Adobe - DNG Codec : For Windows

Whatever it "techincally" or "essentially" is, it allows to view raw files in windows Photo Viewer and creates thumbnails also, as if the raw file was a regular image file (although much bigger and therefore a pain to open and flip through). If You really want to argue over the terminology and technical differences, I suggest writing to Adobe.

No offence

---------- Post added 11-28-2014 at 10:17 AM ----------

So it appears the trouble lies in your computer then........... you're welcome!

That remains to be proven, I will try to open the images on a different computer tonight.

[Al_Kahollick]

That remains to be proven, I will try to open the images on a different computer tonight.

Well, the pics show correctly in camera (jpegs), they show correctly when read directly from the card (raws), apparently they get corrupted somewhere in the transfer process. Good Luck!

[rRnt]

So I opened the raws in another computer, and there was no corruption. Although, the other computer did not have Lightroom (it had the Pentax Digital Camera Utility), so the process was not exactly replicated. Still weird, that computer chooses to corrupt some certain images, and then stick with these even if you import them separately. Well, at least it seems that the camera is okay after all.

Thanks everyone.

[LensBeginner]

Yeah, RAWs are tricky beasts, esp. For beginners...
Sometimes you can't be too sure if you're looking st the embedded jpeg preview or the RAW data...
Glad to hear your pics are safe! :-)