Or you use Adobe's DNG converter to convert all the files to a naming system that makes sense to you. You can use the date and time of creation, as stated, or any other system that suits your fancy.

I think on most cameras it resets, and starts a different directory name. I know if it finds a duplicate file on the card, it just creates another folder for the photos and carries on with the new folder.

Remember that the sensor is only using the center of the image circle. A 20mm lens will give you a moderate wide angle, there are primes down to 14mm available for the digitals.

DNG is available for any manufacturer to use, it's a fully documented format. Leica and another manufacturer are offering it as the RAW format.

It's time the manufacturers got their heads out of their @sses and standardized on one format for RAW so our photos can be opened ten years from now.

There are filters, generally expensve ones, that are especially thin, for use on super-wides. You have to be caeful not to put too much of anything on the front of these lenses.

I use the 12-24 and the 16-45 on the D, and they are both exquisite lenses. Under high magnification you might find a touch of CA with the 12-20, but it's easy to fix in Adobe Camera RAW.

There's a "quick and dirty" method of sharpening that is pretty useful for non-destructive sharpening;

Duplicate background layer.
Apply High Pass filter to the duplicate layer, start off with radius around 10 and experiment.
Change blend mode to Hard Light, and your photo is now sharper.
Adjust opacity to taste.

You can also use Soft Light as a blending mode. Experiment until you find a combination you like.

The benefit is that you don't have to make it the last step - it's a layer, you can turn it off if necessary.

The 16-45 is considered a better lens, but it's also a lot more expensive. What are your needs, how big do you need to print? If you just make 4x6 snapshots, then the lens is certanly not any kind of limitation.

I second that. Use a tripod.

I second the motion. My film cameras are down to two MX's, a K-1000 (more of a collectors item), and an RB67 plus a 4x5. All others are digital.