From: Raphael Bustin on
On Sun, 14 Oct 2007 08:41:33 -0600, "Roger N. Clark (change username
to rnclark)" <username(a)qwest.net> wrote:


>Hmmm 200 inch/3.5 inch = 57 times the aperture.
>I have taken apart some flatbeds and in the better ones,
>lens aperture is ~3/4 inch or so. I haven't checked
>a 4990, of dedicated film scanner. You're saying
>a dedicated scanner has lenses much larger than 3/4 inch
>(0.75 * 57 = 42-inch aperture lens ;-)?

I was exaggerating a bit. But seriously, the lenses are
hugely different. I'm guessing most flatbeds use something
like a 20 mm focal length, f/8 lens. And about four
mirror bounces in the optical path. The Nikon
scanner uses a 75-80 mm 14-element ED lens with
what looks like an f/3.5 aperture. And exactly one
mirror bounce. The Epson lens assembly weighs about
5 grams, the Nikon is probably about 200 grams.

I have requested V750 scan samples on numerous
occasions for the "scan snippets" page. Nobody's
come forward.

Even better would be a direct V750 vs LS-8000
comparison, though that would take a tiny bit more
effort. Suffice to say the Nikon is still comfortably
ahead of the Epson V700.


>I think you mean dynamic range.

I think I mean bits that represent real information
rather than noise. I'm saying that the limited S/N
of CCD (and means of capturing CCD data) means
that the upper 6 or 7 bits (in a 16 bit capture)
are mostly noise.


rafe b
www.terrapinphoto.com
From: Roger N. Clark (change username to rnclark) on
Raphael Bustin wrote:
> On Sun, 14 Oct 2007 08:41:33 -0600, "Roger N. Clark (change username
> to rnclark)" <username(a)qwest.net> wrote:
>
>
>> Hmmm 200 inch/3.5 inch = 57 times the aperture.
>> I have taken apart some flatbeds and in the better ones,
>> lens aperture is ~3/4 inch or so. I haven't checked
>> a 4990, of dedicated film scanner. You're saying
>> a dedicated scanner has lenses much larger than 3/4 inch
>> (0.75 * 57 = 42-inch aperture lens ;-)?
>
> I was exaggerating a bit. But seriously, the lenses are
> hugely different. I'm guessing most flatbeds use something
> like a 20 mm focal length, f/8 lens. And about four
> mirror bounces in the optical path. The Nikon
> scanner uses a 75-80 mm 14-element ED lens with
> what looks like an f/3.5 aperture.

Hmmm... I bet the f/8 lens has better performance ;-).
The point is that a 14-element lens working at f/3.5
may not necessarily perform better on a 2d slide than
a simpler lens at f/8 with a larger linear sensor.

And exactly one
> mirror bounce. The Epson lens assembly weighs about
> 5 grams, the Nikon is probably about 200 grams.

The mirrors will not affect image quality in any meaningful
way.
>
> I have requested V750 scan samples on numerous
> occasions for the "scan snippets" page. Nobody's
> come forward.

Yes, it would be nice to see.
>
> Even better would be a direct V750 vs LS-8000
> comparison, though that would take a tiny bit more
> effort. Suffice to say the Nikon is still comfortably
> ahead of the Epson V700.

I don't dispute this. I would like to see examples too.

>> I think you mean dynamic range.
>
> I think I mean bits that represent real information
> rather than noise. I'm saying that the limited S/N
> of CCD (and means of capturing CCD data) means
> that the upper 6 or 7 bits (in a 16 bit capture)
> are mostly noise.

Signals anywhere above the lowest couple of stops are
photon noise limited. And that is directly proportional
the the pixel size, with larger pixels collecting more photons.
What size CCD is in a Nikon LS-8000?

Remember flatbeds are designed to do large film too.
E.g., doesn't the V750 do 6000 ppi over 4x5 inches.
That's 6000*4 = 24,000 pixels wide! Of which,
I would guess 10,000 pixels gives ~50% MTF.

Roger
From: tinnews on
In comp.periphs.scanners Raphael Bustin <rafeb(a)speakeasy.net> wrote:
>
> I have requested V750 scan samples on numerous
> occasions for the "scan snippets" page. Nobody's
> come forward.
>
> Even better would be a direct V750 vs LS-8000
> comparison, though that would take a tiny bit more
> effort. Suffice to say the Nikon is still comfortably
> ahead of the Epson V700.
>
So no one has done a direct comparison but you still say "the Nikon is
still comfortably ahead of the Epson V700.". :-)
>
--
Chris Green
From: Raphael Bustin on
On 15 Oct 2007 09:02:07 GMT, tinnews(a)isbd.co.uk wrote:

>In comp.periphs.scanners Raphael Bustin <rafeb(a)speakeasy.net> wrote:
>>
>> I have requested V750 scan samples on numerous
>> occasions for the "scan snippets" page. Nobody's
>> come forward.
>>
>> Even better would be a direct V750 vs LS-8000
>> comparison, though that would take a tiny bit more
>> effort. Suffice to say the Nikon is still comfortably
>> ahead of the Epson V700.
>>
>So no one has done a direct comparison but you still say "the Nikon is
>still comfortably ahead of the Epson V700.". :-)
>>

The comparison to the V700 has been posted for
a year or so now.

www.terrapinphoto.com/jmdavis


rafe b
www.terrapinphoto.com
From: Tony on

"Raphael Bustin" <rafeb(a)speakeasy.net> wrote in message
news:con6h3pui5rvn2e0sqiusndq1usv3jse1u(a)4ax.com...
> On 15 Oct 2007 09:02:07 GMT, tinnews(a)isbd.co.uk wrote:
>
>>In comp.periphs.scanners Raphael Bustin <rafeb(a)speakeasy.net> wrote:
>>>
>>> I have requested V750 scan samples on numerous
>>> occasions for the "scan snippets" page. Nobody's
>>> come forward.
>>>
>>> Even better would be a direct V750 vs LS-8000
>>> comparison, though that would take a tiny bit more
>>> effort. Suffice to say the Nikon is still comfortably
>>> ahead of the Epson V700.
>>>
>>So no one has done a direct comparison but you still say "the Nikon is
>>still comfortably ahead of the Epson V700.". :-)
>>>
>
> The comparison to the V700 has been posted for
> a year or so now.
>
> www.terrapinphoto.com/jmdavis
>
>
> rafe b
> www.terrapinphoto.com

Frankly, these two

http://www.terrapinphoto.com/jmdavis/bridgewater_nikon.jpg

http://www.terrapinphoto.com/jmdavis/v700_4_5mm_usm_2_75.jpg

seem pretty darn close.


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