RAW

Digital photographers use some fairly understandable formats like jpeg (used by everyone), psd (used by Photoshop users), tiff (used by people with big harddisks) and so on.

Then there is the mystical raw format which only high end cameras have.

Raw is not even really an image format. Raw is a dump of exactly what the camera sees when you press the shutter-release button.

Different cameras are made in different ways, so they see different things, of course, and therefore there are different RAW formats. My Nikon cameras call their raw files nef (Nikon Electronic Format). The format of these files is not the same as raw files from a Canon or a Pentax. It is not even the same format in my D40X and my D300. A program that can open one of them may not open the other.

Photoshop CS2 does not open my D300 nef files, so I have to convert them in some way to process them in Photoshop.

Some people claim that you never need raw files. They say that you can use jpeg for all your photos. That is clearly a lie. Any conversion from what the camera sees to any other format makes you lose some information. If you convert to small jpeg pictures you lose a lot of information. If you convert to big tiff pictures you hardly lose anything at all, but you do lose some things.

A tiff is lossless, that is, it does not lose any information in a picture. However, the raw file contains more information than just pixel by pixel image information. When you convert to tiff, this additional information is lost or distorted. And that may be just the information you needed.

Now, it is true that for most users most pictures are perfectly fine as jpeg. Nevertheless, for some users in some situations raw files are life savers.

Adobe Camera Raw