I have a 1 gig microdrive and usually when it is empty, I can get 105 images. Well, I had one image on the card and my D100 showed only 95 images left to take. I deleted the one image and then it went to 96. The D100 confirmed there were no images on the card. So, I did a format in the camera and when it finished, it showed 107. Anyone else experience weird results like this?
The number of images that the D100 is displaying is based upon what is on the card at that time. When an image is stored, the camera recaluculates the number images based upon whats on the card. As you know each image has a different size depending upon what has been photographed, i.e. and image with lots of colors may be larger than and images with very few colors, and this affects the number of images a CF Card can hold. File size is also dependant upon format used to save the image, compression, etc.
I had heard that by simply deleting the images from a card some residual information may remain on the card and that by reformating the card this residual information will also be gotten rid of. This seems likely as you got more space on your card after reformating it. It was a discussion on this site on wether to reformat or not the had this info.
When you delete a file in the FAT file system, it really just changes a few attributes to the file so that the disk thinks the image isn't there anymore. So there is a little junk left behind that a device may still count as used space. Formatting changes the state of the media to all zeroes, which just about any device considers to be "empty".
As far as the differences in capactiy between a microdrive and a compact flash card of the same size, I'd imagine it has to do with the physical characteristics of the chips in the card compared to the physical platters of the microdrive. Also keep in mind that 1 megabyte isn't 1,000,000 bytes but is actually 2^20, or 1,048,576 bytes. This often accounts for the differences people notice between the formatted size of a disk and the size advertised by the manufacturer.
Format your card. If you have a card reader on your PC, do it there; FAT, not FAT32. Do it every time you dump your card. DOS uses some space in the file allocation table (FAT) keeping track of the deleted sectors (files). You may also have some bad sectors on the card. They are nothing to worry about if your FAT knows about them, but they will decrease capacity.
I theory, the D100 should do the same thing, but I don't think it reclaims lost clusters. Windows or DOS format will rewrite the FAT with all sectors available and contiguous (except those in the bad sector table). If you have lost clusters, they are reclaimed. Lost clusters happen when something unexpected happens--like you remove the card during a write.
C*n*n camera software is DOS. The firmware is drive A: and the CF card is drive C:. Digital C*n*n owners have a hayday hacking the firmware.
I assume you are shooting RAW to get "only" 107 from 1 gig. Anyway I found that in all types of cards, I have microdrive and CF, I get more shots then are indicated on the LCD screen. Sometimes I get 10% more others 5%. so I stopped looking at the exact count and carry a second CF so when I run out of space, I pop in another CF.
Have been using microdrives for more than a year, with D100 firmware 2.0. Always 107 NEF no more no less. After about 60 000 shots, my D100 mirror failed, and replaced. But my microdrive is always 107.
Pinky Mirror Nikonians@Jakarta,Indonesia-- it's near Bali, if you don't know where it is
I meant to mention that if you have access to a 16 bit Windows OS you can use Scandisk to fix problems that format won't fix. 16 bit windows is really DOS with a windows shell (lipstick on a pig as it's called). Windows 95, 98, or Migraine Edition should have Scandisk.exe in the windows/system folder. It's a program worth having for CF cards.