Having recently purchased a Nikon LS-4000ED scanner after much research and
consideration, I have been experimenting with the much noted and much debated
issue of Nikon's shallow Depth of Field deficiency. Given my results, I
thought I'd put them out here on the board and see if my results really fall in
the minority.
As a brief background, let me just state that I have spent my first few weeks
as an LS4000 owner vigorously testing the various settings in order to
establish a standard config for the next few thousand images I need to scan.
For me, the issue of whether to use ICE, GEM, ROC, MultiSampling and which Film
Strip Holder needed to be tested, weighed and set prior to the big job rather
than during. I just have so many scans ahead of me that I don't want to find
myself in a position of late discovery that necessitates a whole bunch of
rescans..
Please don't get me wrong; I'm not offering up my methodology here or the fact
that I even have a methodology as something supposedly ingenious or radical as
I'm sure most folks who subscribe to this list follow a logical and reasoned
approach to their scanning as well. Rather, I just want to outline what my
concerns where starting out and what I was hoping to discover.
For purposes of brevity, I will leave the issue of whether or not to use ICE-3
to another posting and just address my findings on the LS4000's depth of field
issue here (which, in my mind, seems to be a more critical issue anyway).
For me the DOF question seemed multi-factored (but all closely related). The
central questions I needed to find an answer to were:
1. Is the Nikon's reputation for a shallow DOF really, truly deserved? Is it
as bad as some people claim or is it just an occasional problem that has been
unfairly exaggerated over time? (Not trying to cast aspersions here, just
asking sincerely). To this point specifically, I ask those people reporting
dof problems if they are encountering them mostly/only with damaged or
seriously curled film or if the problem is prevalent even with flat to near
flat film? Scanning the filmscanner archives here, I've come upon both
assertions. So thought I might take another polling of interested parties at
this time.
2. Secondarily, I think it would be helpful to try and identify if the dof
problems that have been reported over the last few years are model-specific or
generally characteristic of the whole Nikon filmscanner line. Again, in this
regard, I've read posts in the archives that seem to go both ways on this.
Some say it was more pronounced with the LS2000/LS30 scanners, while others say
its gotten worse with the LS4000/8000/40 scanners.
Unfortunately, I don't know if the lenses have changed between models. But the
argument that some folks have made about the higher resolution capabilities of
the LS4000/8000 scanners requiring more light and therefore a larger lens
aperture (shallower DOF) does make some sense.
3. Lastly, the issue of which Nikon Film holder to use was perhaps the most
critical of the questions as this is something one can actually do something
about (even if it's just choosing one film holder over another).
By far the majority of posts I have come across have been of the mind that
Nikon's motorized auto strip film feeder (usually designated by an SA in its
name; not talking about the optional batch scanning attachment) leads to the
most dof problems and should be avoided for all but the most casual of scans.
The rough consensus seems to be that going with the Strip Film Holder (usually
with a FH designation) is a much better choice, with the best choice of all
being to mount the neg or slide in a glass slide mount that flattens it
completely.
However, most of these warnings seem to name the SA-20 strip film feeder rather
than the SA-21 strip film feeder, which leads me to wonder if most people
encountering this problem are LS2000 users. The LS4000 comes with the SA-21
which is what I did my testing on (results at end).
I followed the basic procedure outlined at this site (which I found listed in
the film scanner archives):
Again, though, this site is written with the LS2000 in mind, though the
procedures used can easily be adapted to the LS4000 in order to measure DOF
variances.
I tested DOF in the pattern described in the above site (center, all edges and
corners, and more), using both the SA-21 Strip Film Feeder and the MA-20 Slide
Mount Adapter in conjunction with the FH-3 Strip Film Holder (all included with
the LS4000). (The Batch Film adapter was not part of my testing).
In additionally, these variables were also tested:
1. LS4000 Orientation: Standing upright vs. on its side.
2. Emulsion: up vs. down.
3. Image placement on strip: at either end of strip vs. in the middle
4. Film strip curling: flat vs. pretty flat
Here are my findings and I would be very interested in learning if anyone has
come across similar results:
STRIP HOLDER VS. MOTORIZED FEEDER:
Virtually NO numerical difference in the range of NikonScan Focus Point
differences when using the SA-21 motorized strip film feeder vs. using the FH-3
Strip Film Holder. The highest range difference I encountered was 27 NikonScan
Focus units and the lowest 9. On average, no difference btwn the different
delivery methods.
In the web site above, critical focus is maintained with a +/-12 Nikon unit
range, and decent focus within a +/-24 range. How this translates to the
LS4000, I don't know.
I have looked at the scans super magnified and tried to discern what makes for
a critical focus range in the LS4000 and what makes for a decently focused
range (using NikonScan focus units) by looking at grain structure, but I fear I
have not been to successful with this method.
EMULSION:
Virtually no difference btwn up or down.
IMAGE PLACEMENT:
Some variation, but nothing consistent. For all intents and purposes, there
seems to be no difference as long as the degree of curling is consistent for
the entire strip.
STRIP CURLING:
Naturally, as one would expect, the flatter the film strip used the less a
change in dof range encountered.
Given the incredible convenience of the SA-21 film strip feeder and the results
I have obtained, I find no reason to avoid using it. I cannot account for my
results running so far in contradiction to the body of posts in the archive. I
wonder if perhaps Nikon, attuned to complaints about the dof issues of their
scanners, has made some mid-model improvements. Perhaps changed a thing or two
in the design of the SA-21 auto feeder so that it is as good as the FH-3 Strip
Film Holder now.
Or perhaps the problem has always been more with the SA-20 strip film feeder
that came with the LS2000 and not the SA-21 that came with the LS 4000. Could
it be that they made the improvement at the time of the model upgrade?
Any thoughts on this would be greatly appreciated.
Thanks,
Derek
golder@netzero.net
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