Doug Kerr
Well-known member
As a consequence of having shot over 10,000 frames with my Canon EOS 40D, I discovered what I consider an anomaly in the folder number management scheme of the EOS 40D.
Perhaps Chuck will care to comment on my observations.
SUMMARY
EOS 20D (for reference)
The EOS 20D places up to 100 (in some cases, 99) files in a folder.
With file numbering set to "continuous", even when a "clean" CF card is inserted, the camera remembers its place in both file and folder numbering sequences. (It is unavoidable that if the file number is remembered, the folder number will be as well: the folder number and file number share two common digits.)
EOS 40D
The EOS 20D places up to 9999 files in a folder.
With file numbering set to "continuous", when a "clean" CF card is inserted, the camera remembers its place in the file number sequence but not in the folder number sequence (the folder number restarts from 100 in such a case).
DETAILED DISCUSSION
EOS 20D
Assume that file numbering is set to continuous.
If the last number used was (to use a path shorthand) 126/2699, the next file would be assigned 127/2700. (Recall that the first two digits of the file number are always the same as the last two digits of the folder number.)
If the last number used was 128/9999, the new file would be assigned 129/0001 (since a file number of 0000 is never used).
This is true regardless of whether or not a "clean" CF card has been put in the camera. In the example above, if the card was "cleaned" after file 128/9999, folder 129 would be established when the next shot was taken.
EOS 40D
Again, assume that file numbering is set to continuous.
The first frame shot becomes 100/0001.
If the last frame shot had been 100/0099, the next file will be assigned 100/0011, and so on, up through 100/9999.
The next file should be 101/0001. And it will, if 100/9999 is still on the card. But let's see what happens if that is not so.
Assume that there on the card files 100/9913 through 100/9999 when a new shot is taken. Then the next frame will in fact be assigned 101/0001 (so of course the folder 101 will be created).
Now lets assume that we continue to shoot through file 101/0363, upload the files (100/9913 through 101/0363) to our computer, and back them up. Then we clean the card (of both files and directories).
Then we take the next shot. Its is assigned folder/file 100/0364!
That is, evidently the 40D does not "remember" where the folder numbering is. It seemingly relies on the folder structure on the card currently in the camera for that clue.
IMPLICATIONS
One might think that this is not a problem, in that there is never any ambiguity in folder/file numbers among the files on any given card at an given time. But it can screw up larger-scale number mismanagement schemes.
In my case, this spoils an opportunity I otherwise would have to completely mechanize my file numbering scheme. On the computer, all my camera files are of this form:
Xnnnnn
where X is an alpha character identifying the camera and nnnnn is a sequence number running from 00001 up.
In the 20D, that means the following transformation of file numbers (I'll use the same shorthand for folder/file names):
105/0526 -> E00526
185/8579 -> E08579
216/1629 -> E11629
I can easily program Downloader Pro to do that for me.
In the case of the 40D, I would want that to work this way:
100/5765 -> F05765
101/0134 -> F10134
103/2176 -> F32176
I can easily program Downloader Pro to do that for me, too.
But, if after I take shot 101/0163 I clean off the card, in which case the next shot becomes 100/0164, Downloader Pro will unavoidably make this transformation:
100/0164 -> F00164
a number that had already been used.
Of course, I put only 1000 files in a directory on the hard drive. Its numerical portion is the same as the first two digits of my 5-digit file number. I am able to program Downloader Pro to do that for me, as well.
So we might think that the case just above would not lead to any risk, as the duplicate file "F00164" (which should have become F01165) would go into folder "F01" on the hard drive, and I could fix the file number by hand later.
But with the folder numbering on the hard drive mechanized by Downloader Pro, the file would have gone into folder F00, which already held a (different) file F00164, which would have been overwritten.
So I have to use a scheme that requires manual intervention whenever the file number turns over from 9999 to 0001 (whenever the folder number advances). That's not a bit deal, as I don't shoot at a rate that makes this a frequent event.
But is it disappointing than apparently Canon has not well implemented its "larger folder" scheme (in this manifestation).
I suspect that in the 1D3, 1Ds3 and 5D series cameras, where there is a more elaborate way to control the establishment of folders, this anomaly may not exist.
Perhaps Chuck will care to comment on my observations.
SUMMARY
EOS 20D (for reference)
The EOS 20D places up to 100 (in some cases, 99) files in a folder.
With file numbering set to "continuous", even when a "clean" CF card is inserted, the camera remembers its place in both file and folder numbering sequences. (It is unavoidable that if the file number is remembered, the folder number will be as well: the folder number and file number share two common digits.)
EOS 40D
The EOS 20D places up to 9999 files in a folder.
With file numbering set to "continuous", when a "clean" CF card is inserted, the camera remembers its place in the file number sequence but not in the folder number sequence (the folder number restarts from 100 in such a case).
DETAILED DISCUSSION
EOS 20D
Assume that file numbering is set to continuous.
If the last number used was (to use a path shorthand) 126/2699, the next file would be assigned 127/2700. (Recall that the first two digits of the file number are always the same as the last two digits of the folder number.)
If the last number used was 128/9999, the new file would be assigned 129/0001 (since a file number of 0000 is never used).
This is true regardless of whether or not a "clean" CF card has been put in the camera. In the example above, if the card was "cleaned" after file 128/9999, folder 129 would be established when the next shot was taken.
EOS 40D
Again, assume that file numbering is set to continuous.
The first frame shot becomes 100/0001.
If the last frame shot had been 100/0099, the next file will be assigned 100/0011, and so on, up through 100/9999.
The next file should be 101/0001. And it will, if 100/9999 is still on the card. But let's see what happens if that is not so.
Assume that there on the card files 100/9913 through 100/9999 when a new shot is taken. Then the next frame will in fact be assigned 101/0001 (so of course the folder 101 will be created).
Now lets assume that we continue to shoot through file 101/0363, upload the files (100/9913 through 101/0363) to our computer, and back them up. Then we clean the card (of both files and directories).
Then we take the next shot. Its is assigned folder/file 100/0364!
That is, evidently the 40D does not "remember" where the folder numbering is. It seemingly relies on the folder structure on the card currently in the camera for that clue.
IMPLICATIONS
One might think that this is not a problem, in that there is never any ambiguity in folder/file numbers among the files on any given card at an given time. But it can screw up larger-scale number mismanagement schemes.
In my case, this spoils an opportunity I otherwise would have to completely mechanize my file numbering scheme. On the computer, all my camera files are of this form:
Xnnnnn
where X is an alpha character identifying the camera and nnnnn is a sequence number running from 00001 up.
In the 20D, that means the following transformation of file numbers (I'll use the same shorthand for folder/file names):
105/0526 -> E00526
185/8579 -> E08579
216/1629 -> E11629
I can easily program Downloader Pro to do that for me.
In the case of the 40D, I would want that to work this way:
100/5765 -> F05765
101/0134 -> F10134
103/2176 -> F32176
I can easily program Downloader Pro to do that for me, too.
But, if after I take shot 101/0163 I clean off the card, in which case the next shot becomes 100/0164, Downloader Pro will unavoidably make this transformation:
100/0164 -> F00164
a number that had already been used.
Of course, I put only 1000 files in a directory on the hard drive. Its numerical portion is the same as the first two digits of my 5-digit file number. I am able to program Downloader Pro to do that for me, as well.
So we might think that the case just above would not lead to any risk, as the duplicate file "F00164" (which should have become F01165) would go into folder "F01" on the hard drive, and I could fix the file number by hand later.
But with the folder numbering on the hard drive mechanized by Downloader Pro, the file would have gone into folder F00, which already held a (different) file F00164, which would have been overwritten.
So I have to use a scheme that requires manual intervention whenever the file number turns over from 9999 to 0001 (whenever the folder number advances). That's not a bit deal, as I don't shoot at a rate that makes this a frequent event.
But is it disappointing than apparently Canon has not well implemented its "larger folder" scheme (in this manifestation).
I suspect that in the 1D3, 1Ds3 and 5D series cameras, where there is a more elaborate way to control the establishment of folders, this anomaly may not exist.