Corrupted photos after transfer to the pc

Nebezpeci Mys

Hi Guys,

I'm looking for help and was wondering if anyone here has come across this...

Got second-hand Canon 7d a few months back and am having troubles with corrupted photos - they show fine in camera and also if I hook the camera to the pc. However, once the raw files are copied on to the HDD some of them are showing blocks of pink&blue stripes and white areas (example below).

At the begining I thought it was just an issue with Lightroom, so re-installed the whole thing and started checking the images in RAW viewer before imports. But that didn't work, so I started using different memory cards, stoped using the in-built card reader in the pc, started using different USB ports for my USB card reader and also tried to copy the photos directly from the camera through a cable - each of them yielded mixed results with some photos corrupted nearly every single time.

Yet, when I repeated the 'copying process' for the selected corrupted files I was able to get a fine copy from the camera through a cable (and the same USB port).

To me it seems that I've already eliminated all the potential failure factors, so am left with the only other alternative suggesting that I can't execute simple 'ctrl+c' & 'ctrl+v'...

Any help would be greatly appreciated...

hbr

Nebezpeci Mys wrote: »

Hi Guys,

I'm looking for help and was wondering if anyone here has come across this...

Got second-hand Canon 7d a few months back and am having troubles with corrupted photos - they show fine in camera and also if I hook the camera to the pc.

If they show properly in the camera, that suggests that the files are ok.
Are you shooting RAW only or RAW+JPEG?

However, once the raw files are copied on to the HDD some of them are showing blocks of pink&blue stripes and white areas (example below).

Are the files on the camera and the files on the PC exactly the same size?
You PC filesystem should report any errors when you transfer them to the
computer. It might be a good idea to run them through some integrity
checking software. Md5sum or SHAsum can be used to check for file
corruption.

At the begining I thought it was just an issue with Lightroom, so re-installed the whole thing and started checking the images in RAW viewer before imports.

It certainly seems like a RAW conversion problem. It may also be a driver
issue. Some (all?) Canon DSLRs don't use the usual usb-mass-storage system.
They use a modified version of a transfer protocol called PTP.

Yet, when I repeated the 'copying process' for the selected corrupted files I was able to get a fine copy from the camera through a cable (and the same USB port).

You need to establish whether the files are actually corrupt by comparing the
working and non-working versions. The simplest test is to compare file size
in bytes. A more reliable test is to generate a checksum for the working version
and then then check the non-working file to see if the checksum returns a
different result.

For example:
md5sum *.CR2
29ac24b3f3d4c14649440c8ec62ec0b5 suspect.CR2
29ac24b3f3d4c14649440c8ec62ec0b5 working.CR2

In this case, the two files are identical.

To me it seems that I've already eliminated all the potential failure factors, so am left with the only other alternative suggesting that I can't execute simple 'ctrl+c' & 'ctrl+v'...

Any help would be greatly appreciated...

You need to isolate the problem. If the files are corrupt, you need to
check the hardware.

Copy the files from camera to PC using USB. Problems
could be caused by a bad cable or USB sockets. The USB
socket on Canon DSLRs is quite fragile.

Copy the files from card to PC using a card reader. Problems
could be caused by a bad cable or card reader.

Or the software.

Checksum suspect files against known good files as above.
Try a different RAW converter. Is this problem confined to RAW
or do you have problems with JPEG too? Did you have to install
Canon drivers? What OS are you using?

pullandbang

This might help.

Before importing into LR I copy the RAW files from my CF card to a desktop folder using a card reader. I can then check the pics using the Canon software (Zoom Browser) and dump whatever I don't want. You should be able to view your Raws in Zoom Browser if they are not corrupt. (Remember the pic on your camera screen is actually a little jpeg - not a RAW file).

Then when importing into LR3, I "Copy as DNG" rather than importing CR2 files. The reason for changing them to DNG is a whole other debate but the main reason is future proofing. The slightly smaller file size is a bonus.

Nebezpeci Mys

@hbr

Thanks a million - will try the checksum and see. I shoot RAW only, have no problems with JPEGs at all and I'm working of Windows 7. Canon drivers? No, idea...I 'inherited' the pc - its previous owner had the same type of camera, so I assume that the drivers were already on it when the computer arrived to me.

In relation to the isolation of the issue - that's a completely different story. It happened to me with 3 different memory cards, 2 different cables and 2 pc's and - recently - also to my other half with his camera and his pc.

After a bit more digging we concluded that this is a known issue with the particular model, so we will probably just have to hope that new versions of firmware will address it.

Thank you very much for your help, guys.