RE: [APML] Epson 4870 astro-scans

["Dale Ireland" <direland@drdale.com>]

Hello
Very fast preliminary test (not astro image) lots more to test
I just got the 4870. I also have a Polaroid Sprintscan 4000 (not the Plus)
and a Microtek 4000tf. I got the 4000tf to replace the SC4000 because I
wanted to get rid of scsi cards and I have had compatibility problems with
the old sc4000 and windows XP Pro. The 4000tf has firewire or USB and so
does the 4870 so I firewire daisy chain them into one 1394 port.
The SC4000 is supposed to have 3.4-3.8 dynamic range (the plus is supposed
to have 4.2). The Microtek 4.2, and the 4870 3.8 and higher resolution
4800X9600.

I chose an ektachrome 200 test slide, landscape with range from white clouds
to very dark shadow, for my very unscientific test. Auto settings for slide
film.

Resolution: all three had very similar resolution, separating fine tree
limbs in high contrast areas and grass blades in lower contrast area. The
4870 had very slightly lower resolution than two dedicated film scanners in
the high contrast areas. The sc4000 slightly edged the 4000tf in resolution
but seemed to do it with a slightly more contrasty scan. A slight contrast
adjustment in the 4000tf image made the two identical. I even tried the
Epson at the higher interpolated resolution making files up to 130MB and the
resolution was still almost exactly the same as the 4000's

Shadow detail: The two 4000's were identical in the shadows even though the
4000tf is 48 bit and rated higher dynamic range. The 4870 was very far
behind, revealing little or no detail in shadow areas brought out well by
the two 4000's. Someone smarter than I can address the Dmax issue. These
were automatic settings for slide film. I haven't had time to try RAW scans.
The failure of the Epson in shadow areas may be due to it's auto settings.

These tests were single passes in VueScan and in the Epson scanning
software. Much more might be possible with multiple scans at different
settings and in RAW mode. 

Bottom line: for $450 you can get a flatbed scanner and a film scanner that
is very close to the quality of the best "consumer" dedicated film scanners.


Dale


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