Whats causing this data loss (if thats what it is)

I seem to be getting deterioration in my photos (1 in every 500) with my Canon 300 and 40d.

Every now and then, i get, what seems like data loss in the photos, often monthes after i have taken the photo and im not sure whats causing it.

I have never had this problem with my Casio or Minolta shots, so im guessing its due to something in the Canon images?

I took this shot a couple of monthes ago, and its just gone like this, however some of my holiday shots appeared after i got them home.

Byte size: ZERO | Content warning: NOT AN IMAGE

It'll probably be your card reader or CF card.

But the images are fine for a long period before it happens, its not instant...???

ok on second reading, thats very weird!

Hmm, yeah that is abnormal. I can only assume some kind of file corruption in the program you are using to store the photos. May be corrupting them somehow. Not sure though.

twofruitz wrote in post #4168900
I seem to be getting deterioration in my photos (1 in every 500) with my Canon 300 and 40d.

Every now and then, i get, what seems like data loss in the photos, often monthes after i have taken the photo and im not sure whats causing it.

I have never had this problem with my Casio or Minolta shots, so im guessing its due to something in the Canon images?

Where are the photos in question stored? From the amount of time since the shot was taken, it sounds like they're stored on your computer.

Are they stored on your hard drive? Do you archive them to some more permanent type of storage (say, CD-R or DVD)?

If they're stored on your hard drive, then I would be very suspicious of the integrity of the computer at this point, and would strongly consider copying all the images to someplace safe and reinstalling the operating system (and all the applications, of course) from scratch, perhaps after giving the hardware a thorough inspection (by someone who knows what they're doing if you're not comfortable doing that yourself).

Here's hoping there isn't anything seriously wrong with your computer...

EDIT: with any luck, the problem is with your RAM and not with your hard drive. The image you posted looks suspiciously like a single-bit error in the image or something like that. Do the bad images consistently show their defect even across reboots of the computer?

Thanks for the reply.

The images are stored on an external hard drive and like i said, the issue is rare (1 in 500 or so). I built the computer and its been completely reliable and the RAM should be great.

I am guessing its an issue with Paint Shop Pro IX clashing with the image data from the Canon EOS series????

It's probably more likely something to do with the external drive (at a guess).

If it's a problem with the application then you should be able to verify that easily ... by opening the file in a different application (such as Canon's DPP).

Unless you're using ECC RAM, it's impossible to say with any certainty whether it's good or not unless you've recently run it through a thorough test, which is generally a time-consuming affair. That's true even if it's brand new. I use ECC memory exclusively because a failure in memory is something I absolutely, positively want to know about before it starts to cause invisible data corruption.

EDIT: the reason I'm reluctant to suspect the drive is that the drive has error correction built into the way it stores data. When it detects any corruption in a block, it remaps the bad blocks to different areas of the disk transparently so that it can continue to function. If your image were corrupt in that fashion (which would only happen if the error in question was detectable but uncorrectable) you'd see the "bad" portion of it as completely missing. I don't know if there's a similar amount of error correction happening on the bus (USB or firewire, depending on what you're using) but I wouldn't be surprised if there is. The chance of an undetectable error happening on the drive is very, very low -- low enough that I could maybe see it happening once to one of your images like this, but not more than once.

Notice that the area on the left side strip is not affected??? I cant see Ram giving uniform data loss?

Each image was taken TOTALLY seperate (different gear and computer app)

twofruitz wrote in post #4169014
Notice that the area on the left side strip is not affected??? I cant see Ram giving uniform data loss?

Each image was taken TOTALLY seperate (different gear and computer app)

Both jpeg and raw files are stored in a compressed format, so a single bit error could easily cause the symptoms you're seeing. Such an error is much more likely to come from bad memory than from anything else. But I can see how it might be possible for such an error to occur on the USB bus (or firewire, if that's what you're using), such that the drive has no idea that anything went wrong.

Regardless, at this point I would take the drive with your photos, put it on a known good computer, and copy all the photos to an entirely different disk. I would also do a thorough memory test on the computer, and replace the drive enclosure (if not the drive itself as well) and the connecting cable.


In other words: make a backup right now onto known good hardware, while you still can.

I'd be confident this is bad RAM. I had a computer at a place where I worked exibit this exact problem, only it wasn't 1 in 500 images it did this too, but more like 1 in 10.

Turned out the RAM was overheating for some reason - replaced the RAM and it never currupted an image again.

Of course, your mileage may vary.

Thankyou so much for your help guys...

I will endevour to replace the ram and see how i go.

Before you just go ahead and replace the RAM, it might be worth trying Memtest ( http://www.memtest86.c​om/ ) to give your RAM a workout and see how it holds up.

Download the ISO, burn to CD, and boot from the CD. It will run through a whole series of tests and report any problems.