Minimizing Moire patterns when scanning large format negat..

You all are referring to the scanner's DOF as it relates its ability to keep
in focus as much of the THICKNESS of the neg/tranny that's being scanned,
not the actual DOF in the image, right?\

The actual DOF in the image is controlled at the time of shooting, not the
process of scanning.



"Nicholas O. Lindan" <see.DeleteThis@sig.com> wrote in message
news:wereg.6241$921.5383@newsread4.news.pas.earthlink.net...
> "J. L. Jones" wrote
>
>> David J. Littleboy wrote:
>> > ... scanning at 800 ppi, which means DOF is a
>> > lot deeper than at 4800 ppi.
>> Why would DOF be increased when scanning at a lower
>> resolution?
>
> Does sound a little barseackward at first blush, doesn't it?
>
> Reason being that fuzzy doesn't make much difference as
> long as the fuzzy is less than the scanning resolution
> [it gets a bit more complicated than that but not so much it
> really matters]. Lower scanning resolution == more fuzzy that
> can be tolerated == larger "Circle of Confusion" == greater DOF.
>
> Same logic as print size affecting depth of field. DOF isn't one
> number: it changes with how big the print is and how sharp you
> want the print to be.
>
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith DeleteThis @abriget.com> wrote:
> You all are referring to the scanner's DOF as it relates its ability to
> keep in focus as much of the THICKNESS of the neg/tranny that's being
> scanned, not the actual DOF in the image, right?\

Yes. The range at the film plane of the film itself that will appear sharp
at the pixel level in the scan.

> The actual DOF in the image is controlled at the time of shooting, not the
> process of scanning.

Of course. A scanner is a "camera" that takes a "photograph" of a piece of
film that often isn't as flat as the scanner requires.

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

Thanks for the reply David.

I assume this all means that scanners probably don't have much DOF at all
given the thinness of most film materials.

One would think that the manufacturers would have come up with something by
now (at least in high end scanners) such as autofocus for the scanner
lens???



"David J. Littleboy" <davidjl.TakeThisOut@gol.com> wrote in message
news:e5dlgc$90p$2@nnrp.gol.com...
>
> "Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote:
>> You all are referring to the scanner's DOF as it relates its ability to
>> keep in focus as much of the THICKNESS of the neg/tranny that's being
>> scanned, not the actual DOF in the image, right?\
>
> Yes. The range at the film plane of the film itself that will appear sharp
> at the pixel level in the scan.
>
>> The actual DOF in the image is controlled at the time of shooting, not
>> the process of scanning.
>
> Of course. A scanner is a "camera" that takes a "photograph" of a piece of
> film that often isn't as flat as the scanner requires.
>
> David J. Littleboy
> Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith.RemoveThis@abriget.com> wrote in message
news:nVseg.88169$TK1.11198@fed1read06...
> Thanks for the reply David.
>
> I assume this all means that scanners probably don't have much DOF at all
> given the thinness of most film materials.
>
> One would think that the manufacturers would have come up with something
> by now (at least in high end scanners) such as autofocus for the scanner
> lens???

Well, drum scanners don't have this issue, the dedicated small-format
scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it can
be hard to get the film flat enough), and I don't know what life is like
with the subminiature format (35mm) scanners.

I _think_ that the new Epson V700 has a two-position focus; at the glass for
the low-res lens and a couple of mm above the glass for the high-res lens.

But the problem is that the film curves and can't all be in the plane of
optimum focus unless you do something heroic (like wet mounting).

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

This is all making me seriously think of going back to Platinum printing for
my 5x7 negs. No problem with focusing there!


"David J. Littleboy" <davidjl.TakeThisOut@gol.com> wrote in message
news:e5dmc7$95q$1@nnrp.gol.com...
>
> "Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote in message
> news:nVseg.88169$TK1.11198@fed1read06...
>> Thanks for the reply David.
>>
>> I assume this all means that scanners probably don't have much DOF at all
>> given the thinness of most film materials.
>>
>> One would think that the manufacturers would have come up with something
>> by now (at least in high end scanners) such as autofocus for the scanner
>> lens???
>
> Well, drum scanners don't have this issue, the dedicated small-format
> scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it
> can be hard to get the film flat enough), and I don't know what life is
> like with the subminiature format (35mm) scanners.
>
> I _think_ that the new Epson V700 has a two-position focus; at the glass
> for the low-res lens and a couple of mm above the glass for the high-res
> lens.
>
> But the problem is that the film curves and can't all be in the plane of
> optimum focus unless you do something heroic (like wet mounting).
>
> David J. Littleboy
> Tokyo, Japan
>
>
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

David J. Littleboy spake thus:

> "Terry Smith" <TMSmith DeleteThis @abriget.com> wrote in message
> news:nVseg.88169$TK1.11198@fed1read06...
>
>>Thanks for the reply David.
>>
>>I assume this all means that scanners probably don't have much DOF at all
>>given the thinness of most film materials.
>>
>>One would think that the manufacturers would have come up with something
>>by now (at least in high end scanners) such as autofocus for the scanner
>>lens???
>
> Well, drum scanners don't have this issue, the dedicated small-format
> scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it can
> be hard to get the film flat enough), and I don't know what life is like
> with the subminiature format (35mm) scanners.
>
> I _think_ that the new Epson V700 has a two-position focus; at the glass for
> the low-res lens and a couple of mm above the glass for the high-res lens.
>
> But the problem is that the film curves and can't all be in the plane of
> optimum focus unless you do something heroic (like wet mounting).

How about a vacuum board? That might solve the flatness problem. It's
worked in similar situations (like plate burners for offset plates) for
millenia. (Well, not really. But a long time.)


--
I hope that in a few years it [Wikipedia] will be so bloated that it
will simply disintegrate, because I can't stand the thought that this
thing might someday actually be used as a serious reference source.
Because in its current form, it's not to be taken seriously at all.

- Horst Prillinger (see
http://homepage.univie.ac.at/horst.prillinger/blog/archives/2004/06/000623.html)
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

But how would the light get through negs and trannies if a vacuum board were
behind them?


"David Nebenzahl" <nobody RemoveThis @but.us.chickens> wrote in message
news:447a5eb0$0$3691$822641b3@news.adtechcomputers.com...
> David J. Littleboy spake thus:
>
>> "Terry Smith" <TMSmith RemoveThis @abriget.com> wrote in message
>> news:nVseg.88169$TK1.11198@fed1read06...
>>
>>>Thanks for the reply David.
>>>
>>>I assume this all means that scanners probably don't have much DOF at all
>>>given the thinness of most film materials.
>>>
>>>One would think that the manufacturers would have come up with something
>>>by now (at least in high end scanners) such as autofocus for the scanner
>>>lens???
>>
>> Well, drum scanners don't have this issue, the dedicated small-format
>> scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it
>> can be hard to get the film flat enough), and I don't know what life is
>> like with the subminiature format (35mm) scanners.
>>
>> I _think_ that the new Epson V700 has a two-position focus; at the glass
>> for the low-res lens and a couple of mm above the glass for the high-res
>> lens.
>>
>> But the problem is that the film curves and can't all be in the plane of
>> optimum focus unless you do something heroic (like wet mounting).
>
> How about a vacuum board? That might solve the flatness problem. It's
> worked in similar situations (like plate burners for offset plates) for
> millenia. (Well, not really. But a long time.)
>
>
> --
> I hope that in a few years it [Wikipedia] will be so bloated that it
> will simply disintegrate, because I can't stand the thought that this
> thing might someday actually be used as a serious reference source.
> Because in its current form, it's not to be taken seriously at all.
>
> - Horst Prillinger (see
> http://homepage.univie.ac.at/horst.prillinger/blog/archives/2004/06/000623.html)
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

Terry Smith spake thus:

> "David Nebenzahl" <nobody DeleteThis @but.us.chickens> wrote in message
> news:447a5eb0$0$3691$822641b3@news.adtechcomputers.com...
>
>>David J. Littleboy spake thus:
>>
>>>"Terry Smith" <TMSmith DeleteThis @abriget.com> wrote in message
>>>news:nVseg.88169$TK1.11198@fed1read06...
>>>
>>>>Thanks for the reply David.
>>>>
>>>>I assume this all means that scanners probably don't have much DOF at all
>>>>given the thinness of most film materials.
>>>>
>>>>One would think that the manufacturers would have come up with something
>>>>by now (at least in high end scanners) such as autofocus for the scanner
>>>>lens???
>>>
>>>Well, drum scanners don't have this issue, the dedicated small-format
>>>scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it
>>>can be hard to get the film flat enough), and I don't know what life is
>>>like with the subminiature format (35mm) scanners.
>>>
>>>I _think_ that the new Epson V700 has a two-position focus; at the glass
>>>for the low-res lens and a couple of mm above the glass for the high-res
>>>lens.
>>>
>>>But the problem is that the film curves and can't all be in the plane of
>>>optimum focus unless you do something heroic (like wet mounting).
>>
>>How about a vacuum board? That might solve the flatness problem. It's
>>worked in similar situations (like plate burners for offset plates) for
>>millenia. (Well, not really. But a long time.)
>
> But how would the light get through negs and trannies if a
> vacuum board were behind them?

Uh, not sure about that one, but you can be certain that Nebenzahl Labs,
GmbH are hard at work on the problem.


--
I hope that in a few years it [Wikipedia] will be so bloated that it
will simply disintegrate, because I can't stand the thought that this
thing might someday actually be used as a serious reference source.
Because in its current form, it's not to be taken seriously at all.

- Horst Prillinger (see
http://homepage.univie.ac.at/horst.prillinger/blog/archives/2004/06/000623.html)
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote

> I assume this all means that scanners probably don't have much DOF at all
> given the thinness of most film materials.

They will scan 3-d objects, ~1/2" of acceptable DOF, at least on
my old h/p.
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

In rec.photo.equipment.large-format David J. Littleboy <davidjl.RemoveThis@gol.com> wrote:
>
> "Terry Smith" <TMSmith.RemoveThis@abriget.com> wrote in message
> news:nVseg.88169$TK1.11198@fed1read06...
> > Thanks for the reply David.
> >
> > I assume this all means that scanners probably don't have much DOF at all
> > given the thinness of most film materials.
> >
> > One would think that the manufacturers would have come up with something
> > by now (at least in high end scanners) such as autofocus for the scanner
> > lens???
>
> Well, drum scanners don't have this issue, the dedicated small-format
> scanners like the Nikon 8000/9000 do have AF (but nasty DOF problems; it can
> be hard to get the film flat enough), and I don't know what life is like
> with the subminiature format (35mm) scanners.
>

They are more or less the same as nikon 8K/9K, and as you can adjust the focus you
can if you really need scan the film frame in stages and adjust the focus for
indifidual parts. Unverified rumours have it that some software / scanner combos
manage to do this automaticly.

>
> David J. Littleboy
> Tokyo, Japan
>
>

--
Sander

+++ Out of cheese error +++
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat..