35mm film scanner questions

On Tue, 14 Mar 2006 17:47:33 -0500, rafe b <rafeb.DeleteThis@foobar.com> wrote:

>The ultimate extension of this theory is a drum scanner, which
>really only images a point -- not even a line. It is, in effect, a
>microscope objective poised over the film, and imaging one
>microscopic circle at a time.

You're ignoring the mechanism for positioning the drum and the sensor.
Any inaccuracy in these mechanisms will ruin your image.
 >> Stay informed about: 35mm film scanner questions 

"AZ Nomad" <aznomad.RemoveThis@PmunOgeBOX.com> wrote in message
news:slrne1gkcd.vip.aznomad@ip70-176-155-130.ph.ph.cox.net...
> On Tue, 14 Mar 2006 17:47:33 -0500, rafe b <rafeb.RemoveThis@foobar.com> wrote:
>
>>The ultimate extension of this theory is a drum scanner, which
>>really only images a point -- not even a line. It is, in effect, a
>>microscope objective poised over the film, and imaging one
>>microscopic circle at a time.
>
> You're ignoring the mechanism for positioning the drum and the sensor.
> Any inaccuracy in these mechanisms will ruin your image.


I did not mean to suggest or imply that "slop" is
acceptable anywhere. I'm simply saying that the
one-dimensional nature of the sensing element is
important to the design in many ways -- and has
advantages over imaging the original in two
dimensions at once (as in an area CCD sensor.)


rafe b
www.terrapinphoto.com
 >> Stay informed about: 35mm film scanner questions 

Stephen Henning wrote:
>>Think image circle. The sensing element in a scanner -- the CCD --
>>only needs to fit neatly along the diameter of that circle. Whereas
>>with film, the entire *area* of the film has to fit in that circle. So
>>with a CCD, you can design for a smaller image circle, which
>>almost always results in a better lens overall. Furthermore, the
>>image is always at the center of the image circle, in in the axis
>>of the film or CCD travel.
>
>
> So you are saying that a good film scanner should be cheap since they
> don't have to do very much and a good lens is very expensive since it
> has to do more than you could every imagine. I don't think that jives
> with reality very well.
>
In addition to the ones mentioned by Rafe, there are at least two more
factors which makes life easy for the scanner lens: fixed magnification, and
not much need for high aperture. And of course no zoom. So indeed, a good
scan lens can be cheaper than a, loosely speaking, 'equally good' camera lens.

-- Hans
 >> Stay informed about: 35mm film scanner questions 

In article <1142503923.604949.216540.RemoveThis@i39g2000cwa.googlegroups.com>,
<mark.thomas.7.RemoveThis@gmail.com> wrote:
>I thought Douglas couldn't possibly outdo his earlier flawed (and now
>withdrawn) pages, but that one is just awe-inspiring.
>
>Anyone else seen a film scan look that bad, from properly exposed and
>developed Kodak 100 film? Frankly, I've never seen film grain look
>that colorful, and yet 'even', from the darkest to the lightest areas -
>so my suspicions are raised as to where that 'grain' actually came
>from.

Yes, it looks like CCD noise to me. But I'm just killfiling larger and
larger bigpond netblocks to avoid him.


--
That was it. Done. The faulty Monk was turned out into the desert where it
could believe what it liked, including the idea that it had been hard done
by. It was allowed to keep its horse, since horses were so cheap to make.
-- Douglas Adams in Dirk Gently's Holistic Detective Agency
 >> Stay informed about: 35mm film scanner questions