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      :: Filmscanners
Filmscanners mailing list archive (filmscanners@halftone.co.uk)

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Re: filmscanners: Canon Flatbed D2400UF



There are two issues involved scanning head speed and data transfer speed.
Unless you have dual interfaces it would be difficult to tell if the
scanning head is held back by a slower interface.

If you consiser a full resolution scan of A4 you get approx
11(inch)*8(inch)*2400*4800*6(16 bit resolution RGB) = roughly 6GB. This will
take a minimum of 67.5 minutes on USB and a minimum of 2 minutes on
firewire.

But since this is really a film scanner list then if we consider the Nikon
4000 claims a 38 second scan time - the best it could achieve via USB is 85
secs. A significant saving I would say but some people are more patient.

Assuming you use this for 35mm transparencies the file size would be about
93Mb this is just over 60 seconds on USB and about 1.86 sec firewire. These
are the limiting speed of the interface in practice the scanning head speed
and how long it takes to position the scanning head all play their part. At
35mm it  may be acceptable. But the problem scales up rapidly for larger
scans. USB would take 46 secs per square inch of scan firewie 1.38 secs per
square inch of scan at best resolution on this scanner. So even medium
format is starting to get slow with USB at these sorts of resolution. The
Nikon spec shows that the scan head could be moving at over twice the USB
speed.

Firewire is 400Mbit per sec (50MB) max , USB is 12Mbit max per sec (1.5MB).

Steve

P.S. How the hell would you process a 6GB image!


----- Original Message -----
From: <glenside@cwcom.net>
To: <filmscanners@halftone.co.uk>
Sent: Thursday, April 05, 2001 12:58 PM
Subject: filmscanners: Canon Flatbed D2400UF


> A few people on the list have mentioned this scanner. PCWORLD the US
magazine
> not the UK store has a test of it at
> http://www.pcworld.com/reviews/article/0,aid,44621,00.asp
>
> They claim that the USB interface is much slower than a SCSI or Firewire
interface
> and this causes it to get a lower score. I have seen this remark a few
times
> in scanner test recently. How can they say this when they obviously have
not
> tested the scanner with a Firewire interface. it could be the scanner that
is
> the bottleneck not the interface.
>
> Or is this being picky
>
>
> Eddie Cairns
>




 




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