I've had my D100 for a while now, and one of the things I've never been able to work out is how to "reset" the folders that the photos are written to on the CF card. Whilst I've not managed to go "round the clock" with it yet, through various uses of the camera, I'd ended up on 111ND100. This isn't really a major problem, but one of those minor niggles.

In the playback menu, there's a folder designate option - this is used to decide where the images that are shown are taken from (for instance, you can use this as a back door to hiding photos). This option, unsuprisingly, doesn't do what I was looking for.

I played about today as I had a few spare minutes - this works. There's probably another way of doing this, but this works for me. Take the CF card out of the camera. On the CSM menu, go to File No Seq (on my D100, it's option 5 of the CSM Menu) There's three options: Yes, No, Reset. Select reset, and then press right. With the CF card out of the camera, stick it into an external reader/writer and delete the existing folders on it. Put the card in to the camera, and take a photo - it'll be called 100ND100\DSC_0001.JPG.

It should really be possible to do this with the card in the camera and without having to delete the existing folders... but it's not (or so it seems)