a Canon 40D bug? - overwrote images on CF card

[nigeldh]

Update after letting RescuePro look for Images files it picked up the .CR2 files. It turns out the "missing" files were still on the card and not overwritten. I had used All Files the first time and only got .TIF images which were not valid.
I hadn't looked at the card via Windows Explorer before erasing the images so I don't know what files were actually on the card, if there was a date gap. I had download the card to my laptop when I was travelling then to my desktop when I got home. I also did a quick skim of the files using Breeze Browser Pro.

1. The "missing images" were there and not overwritten.
2. I was using Downloader Pro but, without having looked at the original files on the card I don't know if there was a date gap in the directory.
a. I suspect that ANY downloading program would have failed. The UDMA would probably only have worked if it was used before 7/27.
b. I put images into folders by date and prepend YYYYMMDD plus the shooting time so I would not have overwritten files with the same file number but taken at a different time.

WAS:
I just got back from a trip out to the Western US. Now I find that there may be a bug in the 40D firmware because a number of images were overwritten by the camera.
Something I have not seen before and I am now up to over 30,000 images taken on this 40D. And over 20,000 images on my 30D.

I started the trip with the camera set to continuous numbering and [2]9370 was the image count.
On 7/25 I took RAW image 9999 on a 32 gig memory card. After that I have no more images until 7/27 when they start with [3]0001.
I look a lot of images after 9999 on 7/25 and 7/26. I know they were there because I was reviewing them and deleting some of the out of focus/clearly bad shots. And I have the camera set to require a CF card.

Unfortunately I filled up this memory card on 7/28 so a recovery utility like Recuva or RescuePro does not find them. Update 8/11 - I used the all files option on RescuePro which found only .TIF files. The Images option found the .CR2 files.

I know that the "next number" in continuous number works because one of the memory cards I used later had some pre 7/23 images on it and the camera used the next available number in that sequence.
And I believe that I filled my second 32 gig CF card with no issues. Then I switched to several 4 gig CF cards I had from a while back.

This might be a case where programmers didn't anticipate more than 999 images on a CF card. Or something with the 9999 rollover and more than 999 images. With the 32 gig memory card I haven't taken enough images to get the camera's top display remaining image count below 999 before this trip.

In hindsight I should have gotten a Colorspace UDMA so I could easily backup my CF cards while driving.

[Ken Bennett]

That is odd and disturbing.

Two questions: 1. Did you remove and replace that card during this time? (That is, did you take out the card, shoot some photos on a different card, then replace the first card and keep shooting?) Are those photos on a different card?

2. I guess this is a comment more than a question, but back in the days of microdrives I learned to *never* delete photos in-camera, and always reformat when putting in a new card. I know that's not considered as important these days, but old habits die hard.

I am very sorry for your loss.

[JeffKohn]

It wouldn't really be too surprising to me if it was a firmware bug. After all the conventional wisdom about not deleting images in-camera dates back to one of the older Canon DSLR's that would overwrite images under certain circumstances if you did so (Was it the 10D?). Can't say that I've never had any problems like this with my Nikon's though.