image quality

[uranium2k]

I have some friends who shoots in raw and immediatly after downloading to the computer, he converts to JPG and edit the jpg file.

Frankly, that is a waste of memory card space and processing time.

The main benefit of RAW files, is that it retains all (or almost everything) information of the photo file.
Thus you can recover more information of the said photo in RAW than JPG.

If you are doing what my friend is doing, I suggest you shoot in JPG and save those memory space.

If that's seriously his process (without doing anything to the RAW file) then it's probably a waste. The important editing should be done at the RAW stage instead of post-conversion to JPG.