RE: [Leica] Film scanner recommendations.

["Tim Atherton" <tim@KairosPhoto.com>]

Here is just one post on the discussion of this problem with Nikon
scanners - it is also a problem I've noticed with Nikons. It is apparently a
depth of field problem due to the lenses Nikon uses. It's a fairly commonly
acknowledged and oft discussed problem. Ed Hamrick who makes the Vuescan
software has had to spend a good deal of time figuring out how to set up the
focussing to cope with this.

Tim A

> -----Original Message-----
> From: owner-filmscanners@halftone.co.uk
> Subject: Re: filmscanners: Canon 4000 scanner VS Nikon LS4000
>
>
> Greetings all--
>
> I'm a bit surprised to see the nature of the comments about  reports of
focus problems; > as if this is a new and unheard
> of issue.  Surely anyone who's been on this list awhile is aware that
> this is a perennial issue with the Nikon filmscanners!
>
> Web reviews that mention focus problems with the Nikon filmscanners
> that I've learned about through this list include:
>
> http://members.austarmetro.com.au/~julian/ls2000-focus.htm
>
> http://www.pytlowany.com/nikontest.html
>
> I also reported here my own experiences with my two-month old Nikon
> LS4000ED only a few weeks ago, complaining about focus problems.  Let
> me reiterate:
>
> o I have thousands of Kodachrome slides dating back twenty years in
> both plastic and cardboard mounts with what I consider "normal"
> degrees of curvature for slides.
>
> o I have a number of these slides where the Nikon cannot produce
> sharp scans across the entire image.
>
> o The NikonScan software lets me place the focus point anywhere on
> the image I like, and will give me razor sharp scans at that point.
> However other regions of the image will consequently become blurry.
>
> o When you manually set the focus point (by clicking the preview
> image where you want the scanner to focus), the scanner will focus at
> that point and report a number.  By clicking around you can compare
> the various focus numbers.
>
> o Regions that are within 6 focus units of the focus point (the
> scanner just gives a number, doesn't say whether this represents
> microns, angstroms, or what) will be substantially as sharp as at the
> focus point.
>
> o Regions that are 12 units different from the focus point will be
> noticeably blurry.
>
> o  I have some slides where I have measured a range of at least 20
> focus units.  On these slides I can click various areas to find the
> range of focus units, set the scanner manually at a number halfway
> in-between, and get the best AVERAGE sharpness across the image.
> HOWEVER, the blurriest parts are blurrier than when I scan the same
> slide with my 4-year-old 2300 dpi filmscanner.
>
> o Therefore on these slides I'm getting 4000 dpi sharpness in certain
> parts of the scan (say the center) and less than 2300 dpi sharpness
> in other parts (say the edges).
>
> o I have not done as much work with negative strips as I have with
> slides. I do see some focus variation across negative images but so
> far it doesn't seem as bad as for my most-curved slides.
>

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