This is a comparison between two negative/slide scanners, the old HP Photosmart and the new Acer Scanwit 2720s.

An attempt was made to make both images show the same nebulosity, the HP scan had to be pushed to come close to the Acer and all kinds of noise show up.

Note the faint reflections of the bright stars seen in the HP scan, this is probably due to internal reflections inside the HP scanner..the Acer does not use mirrors, the CCD directly sees the negative.

I understand that the new HP Photosmart S20 has been improved, and perhaps I could have done a better job with the HP, but its software is difficult to use and manual scanner control is essential for astro images. Check out the HPs scanner review at this web page:

http://www.sphoto.com/photosmt.html

here are the specs on the Acer :

http://www.acerperipherals.com/imaging/scanwit.html

Here are the images:

HP Photosmart (old type)

Acer Scanwit 2720s