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     áòèé÷ :: Filmscanners
Filmscanners mailing list archive (filmscanners@halftone.co.uk)

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[filmscanners] Nikon LS-4000ED Depth of Field Revisited


  • To: lexa@www.lexa.ru
  • Subject: [filmscanners] Nikon LS-4000ED Depth of Field Revisited
  • From: "" <golder@netzero.com>
  • Date: Tue, 21 Jan 2003 09:15:27 GMT
  • Unsubscribe: mailto:listserver@halftone.co.uk

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):

http://members.austarmetro.com.au/~julian/photography/ls2000-focus.htm

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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