quote:
Originally posted by gif83
however making something out of nothing is impossible!
This is true, but you haven't got nothing. If you have a pixel, you generally have the average colour of that portion of screen. By comparing it to the ones around it, or by making a mock comparison by smudging them into one another and comparing it to the unsmudged version (the basis of unsharp masking) you can at least retrieve lost shape from poor focus/definition. Generally what loses out is the precise colour of these shapes... if you apply a nonsharp mask with extreme values, you will get as perfect a shape as you could ask for, but crazy colour contrast.
It really does enhance the raw capabilities of the camera. Astronomers use it all the time to get pictures of stars and galaxies which the hubble telescope just cannot see in focus, and the same can be achieved when improving the quality of cctv footage