LS4000 depth of focus problem--Nikon LS5000 also, or other alternatives?

G

Gary L Hunt

My Nikon LS4000 has always suffered from the widely reported "narrow depth of
focus" problem, which means that in most cases it is impossible to get the
entire slide (or even most of it) in critical focus without resorting to glass
slide mounts. The description of the LS5000 sounds to me as though it is pretty
similar mechanically and optically. Is there any reason to suppose this problem
is less severe with the new model?

And a related question--does the "grain dissolver" diffuser on the Minolta 5400
improve its performance in this respect? My old Polaroid 4000 SprintScan was
never as sharp as the LS4000, but its focus uniformity was very good indeed. With
the Nikon, I wind up having to manually focus it most of the time on a compromise
setting.

Gary Hunt <[email protected]>
 
B

Bart van der Wolf

SNIP
And a related question--does the "grain dissolver" diffuser on the Minolta 5400
improve its performance in this respect?

No, and Yes...

Technically it affects neither resolution* nor depth of field (lens aperture
and distance is unchanged). However, the first giveaway with
out-of-critical-focus is the different rendering of the grain structure,
especially in the corners.
Since graininess is reduced, lack of critical focus is harder to spot.

* It does modify contrast depending on density, so that may affect the
tonality, depending of grain/dye-cloud structure.

Bart
 
R

Roger Halstead

My Nikon LS4000 has always suffered from the widely reported "narrow depth of
focus" problem, which means that in most cases it is impossible to get the
entire slide (or even most of it) in critical focus without resorting to glass

Maybe I'm just not discerning enough but in over 6000 slides in the
last few weeks, I've never noted this problem.
slide mounts. The description of the LS5000 sounds to me as though it is pretty
similar mechanically and optically. Is there any reason to suppose this problem
is less severe with the new model?

I haven't seen any problem. OTHO ask me again in another year of use.
<:))
I'm currently running a whole series of problem negatives through that
require adjustment of the analog gain, color correction, and are super
dense (under exposed). So far, it has make all but one look like new.
And a related question--does the "grain dissolver" diffuser on the Minolta 5400
improve its performance in this respect? My old Polaroid 4000 SprintScan was
never as sharp as the LS4000, but its focus uniformity was very good indeed. With
the Nikon, I wind up having to manually focus it most of the time on a compromise
setting.

In over 6000 slides I've not had to touch the focus once.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
 
G

Gary L Hunt

I don't think it's a matter of how discerning you are but rather what uses you
are making of the scans. If I look at them on the monitor, or make smaller
prints from them, it's not noticeable. And no one else has ever admitted to
noticing it on my enlargements (which are never larger than 11x17 or so).
But if I use the default focus point (in the center), I can see it very clearly
in the corners and edges, although some slides are MUCH worse than others.
(Home-mounted cardboard slide mounts are the worst for me.) And of course
it's partly annoying because I know it's not an optical limitation--if I mount
the slide in glass, then the whole image is sharp. I'm reluctant to archive
scans where all parts of the image are not equally usable for future printing.
 
R

Roger Halstead

I don't think it's a matter of how discerning you are but rather what uses you
are making of the scans. If I look at them on the monitor, or make smaller
prints from them, it's not noticeable. And no one else has ever admitted to
noticing it on my enlargements (which are never larger than 11x17 or so).
But if I use the default focus point (in the center), I can see it very clearly
in the corners and edges, although some slides are MUCH worse than others.
(Home-mounted cardboard slide mounts are the worst for me.) And of course
it's partly annoying because I know it's not an optical limitation--if I mount
the slide in glass, then the whole image is sharp. I'm reluctant to archive
scans where all parts of the image are not equally usable for future printing.
That would explain the difference.
All of the slildes are either Kodak paper mounts (from Kodak), or I
use plastic mounts. Although I do have to admint some of those Kodak
mounts that are 50 years old and have been through a projector or two
a few hundered times... or more <:)) are't all that straight. Then
again those slides are only saved for reference and possibly small
prints at 2000 or 2400 dpi and not 4000.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
 
K

Kennedy McEwen

Roger Halstead said:
I haven't seen any problem. OTHO ask me again in another year of use.
<:))
I'm currently running a whole series of problem negatives through that
require adjustment of the analog gain, color correction, and are super
dense (under exposed).

Why do your negatives need analogue gain adjustment? Negatives usually
don't have enough dynamic range to cause a problem with exposure. Super
dense negatives are usually extremely over-exposed, not under-exposed.

Are you sure you are not talking about slides?
 
R

Roger Halstead

Why do your negatives need analogue gain adjustment? Negatives usually
don't have enough dynamic range to cause a problem with exposure. Super
dense negatives are usually extremely over-exposed, not under-exposed.

Are you sure you are not talking about slides?

I'm sure I am talking about slides, but the guy you are answering was
talking about negatives...I think.

There are two posts mixed in there<:))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
 
T

ThomasH

Roger said:
Maybe I'm just not discerning enough but in over 6000 slides in the
last few weeks, I've never noted this problem.

Same here. I think that is gossip and rumor, which as always
might have something true in its origin: Maybe some of the
LS4000 were misaligned or maybe some of the users tried to
scan (too) warped film?

I haven't seen any problem. OTHO ask me again in another year of use.
<:))
I'm currently running a whole series of problem negatives through that
require adjustment of the analog gain, color correction, and are super
dense (under exposed). So far, it has make all but one look like new.

Exposure problems and foremost color balance handling: yes,
this are the problems which I also experience with NikonScan.
Vuescan is of great help here.

Scan of negatives with NikonScan is also very troubled.
Especially, I notice from the histograms that NikonScan
never maps darkest gray to 0. All histograms seem to
indicate an offset of approx. 25%!

Thomas
 
K

Kennedy McEwen

Roger Halstead said:
I'm sure I am talking about slides,

I thought you must be.
but the guy you are answering was
talking about negatives...I think.
I wasn't answering anyone - I was asking you a question about what you
wrote. Negatives were introduced in the thread in your post - up till
then it had been only Gary's question about focus across glass-less
mounted slides. Did you reply to the correct article? ;-)
There are two posts mixed in there<:))
Not in the section I quoted: 5 lines comprising two sentences separated
by an emoticon - all written by you and posted on 17th March 2004 at
18:11:07GMT (13:11:07 EST). That is the first place in the entire
thread that underexposed negatives were super dense, consequently
requiring analogue gain adjustment, was mentioned.
 
R

Roger Halstead

I thought you must be.

I wasn't answering anyone - I was asking you a question about what you
wrote. Negatives were introduced in the thread in your post - up till
then it had been only Gary's question about focus across glass-less
mounted slides. Did you reply to the correct article? ;-)

Not in the section I quoted: 5 lines comprising two sentences separated
by an emoticon - all written by you and posted on 17th March 2004 at
18:11:07GMT (13:11:07 EST). That is the first place in the entire
thread that underexposed negatives were super dense, consequently
requiring analogue gain adjustment, was mentioned.

My apologies,

I didn't recall the wording and the post wasn't on my
server...However, I went back thorough the <Sent Messages> and lo and
behold, there it was.

Bout the only excuse I can think of at the moment is a plain old
fashioned "brain fart". I have no idea as to why I said negatives,
unless I was thinking of what I have to do after I get through the
slides.

I am going through a bunch of problem slides that are "old", warped,
discolored, scratched, and dirty. I'm definitely not using the SF-210
for these. They are strictly one-at-a-time.

Again, my apologies.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
 
R

Raphael Bustin

Same here. I think that is gossip and rumor, which as always
might have something true in its origin: Maybe some of the
LS4000 were misaligned or maybe some of the users tried to
scan (too) warped film?


Basing on the LS-8000, I'd say the problem is overstated.
But still real. I do a fair amount of fussing with film in holders
and occasionally have to re-load film a few times before
it's flat enough to scan well. 35 mm in strips is generally
no problem. Old slides that have curved or domed in their
mounts can be a b*tch.

Exposure problems and foremost color balance handling: yes,
this are the problems which I also experience with NikonScan.
Vuescan is of great help here.

Scan of negatives with NikonScan is also very troubled.
Especially, I notice from the histograms that NikonScan
never maps darkest gray to 0. All histograms seem to
indicate an offset of approx. 25%!


Try scanning your negatives as positives, and inverting
them in NikonScan. Look up "dane kosaka LS-8000" on
google for a nice site describing the technique.



rafe b.
http://www.terrapinphoto.com
 
K

Kennedy McEwen

Exposure problems and foremost color balance handling: yes,
this are the problems which I also experience with NikonScan.
Vuescan is of great help here.

Scan of negatives with NikonScan is also very troubled.
Especially, I notice from the histograms that NikonScan
never maps darkest gray to 0. All histograms seem to
indicate an offset of approx. 25%!
It does if you tell it to, Thomas. :)

However the default setting results in a black level which depends on
the density of the film base - that is what defines the black point on a
negative. The autoexposure will adjust this to ensure that the CCD
level is matched but not saturated in any of the colour channels and,
once inverted, the saturation level becomes peak black. Consequently
the film base level is therefore offset from this level by an amount
dependent on the density of the film base itself - which varies from
film type to type. I have never seen this get above 10 percent
(histogram black level=25).

There are two simple solutions to this.
First, set a global adjustment to the exposure that brings the black
level to 0 for the film type you use and then save that as the default
user setting or a specific film type setting. This approach has the
disadvantage that the film base can be a slightly different density
depending on the processing used, even on the same film type.
Consequently you might find that some blacks are actually clipped and
you need to rescan at preview level to get acceptable results. The
advantage of this technique is that you get a few percent extra in
dynamic range due to increased exposure and better use of the full CCD
dynamic range. Since negatives don't actually have anything like the
density range that the scanner can cope with, what actually matters is
the improved signal to noise ratio, which is dominated by shot noise on
the illumination itself. In practice the difference is almost
negligible - a 10% increase in exposure improves the SNR by around 3%,
so hardly a big deal. Even at your extreme 25% level, this is only
going to improve things by 5%, which is pretty negligible.

Second approach is just to define a black level on the curves window and
save that as a user default or film type setting. The advantages and
disadvantages of this approach are pretty much complementary to the
first solution.

Given the marginal disadvantage of operating the CCD close to
saturation, I prefer the latter, since I can make minor adjustments to
the black point without getting another preview on the rare occasions
that I just throw film at the scanner without checking which type it is
and choosing a setting I have previously created.

I haven't had NikonScan transfer an image into Photoshop which did not
have a good black level, (or histogram distribution for that matter)
since the day I bought the LS-4000 and started using it.

As for your problems on colour balance - once you get a default setting
that gives good blacks, find or create a test negative with good whites
and grey content - a colour chart is a good start. Then use the eye
droppers in the curves window to determine the white point from the
white areas of the image - you might need to make a few adjustments to
the final levels to give you a safe margin, depending on your preference
settings. Then use the gamma dropper to determine slope correction in
each colour channel from any of the grey sections. Store these with
your defaults for that film as well. Perfect colour balance (or at
least matching the colour of the light the image was shot under) every
time thereafter.
 
N

nikita

"I think that is gossip and rumor".

Well, if you mean the wellknown fact of the narrow depth of focus in
the Nikonscanners, then you're dead wrong.

Nikonscanners have always been suffering from this problem. In the
same way as glassless enlargers always have. Some people never noticed
that.....but the fact was clear. You don't have to
go that close to see that the structure and sharpness of the grain is
blurring away. The depth of focus is helped just a little bit by
stopping down to a smaller f-stop but the lens>filmplanedistance is so
narrow that the problem is still there. A glasscarrier with two
glasses was the only real solution. This was not just an issue with
larger filmformats – even the smaller 35 mm had this. Coldlight
sources helped, but not much. It just hold it more stable but any
curvation was creating problems. Again, the only real solution was
glass on both sides of the film.

This is also a problem in cameras – more than you ever can imagine.
But it's hard to make a distinction between that and bad
lenscorrections. Even my Leica M cams have problems, especially as the
rearlens of the wideangels are so close to the filmplane, they're real
wideangels and of no retrofocusdesign. But the grain will always be
sharp allover when printing with glass. So, one tend to accept that
unsharpness as a bad lenscorrection, but many times it could be a bad
flatness of the film in the camera. It's also wellknown fact that is
just take a single bit of your hair between the lensmpount and lens to
screw up focus accurance when using a wider lens.

The Nikonscanners use a weaker lightsource. The working f-stop has to
be larger. What does that tell you ? There IS a great problem with
focus allover the film with Nikonscanners. It's not hard to check that
out in real world. It doesn't get better with the crappy
filmstripholders made by Nikon. The scanner itself is fantastic, but
it's sad to see what takes it downhills.

nikita
 
T

ThomasH

Raphael said:
[...]
Exposure problems and foremost color balance handling: yes,
this are the problems which I also experience with NikonScan.
Vuescan is of great help here.

Scan of negatives with NikonScan is also very troubled.
Especially, I notice from the histograms that NikonScan
never maps darkest gray to 0. All histograms seem to
indicate an offset of approx. 25%!

Try scanning your negatives as positives, and inverting
them in NikonScan. Look up "dane kosaka LS-8000" on
google for a nice site describing the technique.

rafe b.
http://www.terrapinphoto.com

Thanks for this tip! It was entirely unknown to me!
I will give it a try.

This example unveils though, or confirms rather, a dilemma
which we have with Nikon: rigid structures and inability to
move. This "negative scan bug" can be obviously handled
*using Nikon Scan* only, even on a user interface level.
The more easy would it be to apply it in the software
internally. And yet, after several years of waiting we are
not getting any solution from Nikon.

I have my own collected list of bugs and weaknesses of
NikonScan, such as the thumbnail positioning problem and
exposure problem, of which I posted several examples to
the web.

I also was a few times (especially in the beginning) on phone
with Nikon, directed a few times to Level 2. All this talk,
as good and nice it is, remains worthless if the software will
not be fixed. My purchase of a Canon camera was initiated by
this unspeakable example of arrogance and ignorance presented
by the software department of the (former) undisputed First
Diva in Photography, now dragging behind Canon on the base of
nostalgia... This web page:

http://www.marginalsoftware.com/LS8000Notes/three_easy_ways.htm

reassures me that I am not alone in dealing with this problem.
Photo Magazines resort to the usual approach "Praise the Lord
and all Products made by its Sheep" and somehow... fail to
discover *any* problem with NikonScan. Good that we have web.
We can now address the issues and present them to thousands of
users by ourselves :) Let me guess now: in this particular
case Nikon will not fix the software anyway...

Thomas
 
T

ThomasH

Kennedy said:
It does if you tell it to, Thomas. :)

However the default setting results in a black level which depends on
the density of the film base - that is what defines the black point on a
negative. The autoexposure will adjust this to ensure that the CCD
level is matched but not saturated in any of the colour channels and,
once inverted, the saturation level becomes peak black. Consequently
the film base level is therefore offset from this level by an amount
dependent on the density of the film base itself - which varies from
film type to type. I have never seen this get above 10 percent
(histogram black level=25).

You are correct, my fault. I misspoke by calling this value
on the histogram as a percentage value! It is indeed approx.
10% on the 0..255 scale used by Nikon.

Thomas
 
K

Kennedy McEwen

[QUOTE="ThomasH said:
It does if you tell it to, Thomas. :)

However the default setting results in a black level which depends on
the density of the film base - that is what defines the black point on a
negative. The autoexposure will adjust this to ensure that the CCD
level is matched but not saturated in any of the colour channels and,
once inverted, the saturation level becomes peak black. Consequently
the film base level is therefore offset from this level by an amount
dependent on the density of the film base itself - which varies from
film type to type. I have never seen this get above 10 percent
(histogram black level=25).

You are correct, my fault. I misspoke by calling this value
on the histogram as a percentage value! It is indeed approx.
10% on the 0..255 scale used by Nikon.
[/QUOTE]
Well, I take it back in any case Thomas.

I just remembered some very fogged negatives that I have, very fogged
indeed, and the base level is around 74 on RGB, but over 130 in the red
channel!

Having said that, the suggestions I gave to adjust the black level still
worked although, with the seriously reduced dynamic range of the images,
that simply shifted the white point as well - resulting in further
compression due to the system gamma applied. IMO, the best solution was
still to use the second option.

It seems to me that scanning as a positive and then inverting it in
software would only work in a linear gamma space - although I suppose
that some folks might consider the artificially stretched shadows and
compressed highlights that would result from implementing that method in
normal gamma work space to be preferable to correct gamma.
 
R

Raphael Bustin

Thanks for this tip! It was entirely unknown to me!
I will give it a try.

This example unveils though, or confirms rather, a dilemma
which we have with Nikon: rigid structures and inability to
move. This "negative scan bug" can be obviously handled
*using Nikon Scan* only, even on a user interface level.
The more easy would it be to apply it in the software
internally. And yet, after several years of waiting we are
not getting any solution from Nikon.

I have my own collected list of bugs and weaknesses of
NikonScan, such as the thumbnail positioning problem and
exposure problem, of which I posted several examples to
the web.

<snip>

I've used a number of scanner drivers over the years.

In the overall scheme of things NikonScan isn't bad at all.

It has its quirks and idiosyncracies, but it's generally stable
and gets the job done. It has all the tools I need or expect,
and they work pretty much as I'd expect them to.


rafe b.
http://www.terrapinphoto.com
 
G

Gary L Hunt

"I think that is gossip and rumor".

Well, if you mean the wellknown fact of the narrow depth of focus in
the Nikonscanners, then you're dead wrong.
.....>
The Nikonscanners use a weaker lightsource. The working f-stop has to
be larger. What does that tell you ? There IS a great problem with
focus allover the film with Nikonscanners. It's not hard to check that
out in real world. It doesn't get better with the crappy
filmstripholders made by Nikon. The scanner itself is fantastic, but
it's sad to see what takes it downhills.

nikita

I don't know about the "weaker lightsource", but I do believe the scanner
lens is probably faster (i.e. less DOF), probably in order to speed up
scan times. (It's the fastest by far of the 3 slide scanners I've owned.)
I love most everything about it--except for having razor-sharp slides in
the middle that are visibly blurry at the edges and corners.

There's at least one pretty decent Web page illustrating the DOF problem
(http://members.austarmetro.com.au/~julian/photography/ls2000-focus.htm)
whose results agree very closely with my own experience. If you walk the
autofocus point around over a slide, it's common for the range of settings
to vary by 30-50 "points" or more, and the DOF is maybe about +/-10 for
critical enlargements. If you pick a compromise point for focusing (e.g.
about halfway between the middle and the edge), the central focus is good
over most of the image--but the extreme edges are never in focus, at least
for my cardboard mounted slides. For lots of subjects it doesn't matter.
For landscapes, it does.

The new LS-9000 has some kind of diffuser built into it, evidently in
recognition of this problem, but the LS5000 does not, it turns out. So I'm
still looking for a fast, accurate, auto-feeding, does-everything-but-
make-bread slide scanner with enough DOF for my cardboard-mounted slides.
(Not holding breath.)

Gary Hunt <[email protected]>
 
N

nikita

Gary,

the "weaker lightsource" is LEDs intensitylevels compared to more the
common halogen or whatever used in most other filmscanners. So,
faster/short scantimes in combo with weaker light source means an even
faster lens.....
The lightsource itself is terrific. And it's very gentle with the
film.

Anyway, IF the grain – and the structure of it – is clearly visible,
It's also very disturbing when the grain in some areas of the picture
is halfway into a decent focus while others are razorsharp. Like a bad
use of the treshold value when sharpening with USM. The eye will see
that as we're focusing at the grain as well as the rest of the
"picture sharpness". A slightly blurred grain looks crappy and sloppy.
Sure, different outputs will mask this more or less. But the fact is
still there; it's very difficult to get the whole frame sharp with the
Nikonscanners. Even when using the "compromise focus point method" it
mostly fails to deliver. It depends so much on where in the
filmstripholder/autofeeder (or whatever in use) the filmframe is
located. It's not an equal corner to corner situation over the frame.
Then add differences in air humidity. In dry areas of the world, film
will curve with a lot of strenght. This easily bends the filmholder
differently in the weak parts. In the outer end of the holder it
pushes the filmplane more. In such situation the compromise
focusingpoint is justy a dream. The trial and error method is kind of
frustrating.....

The glass on both side is the optimal, but a workaround with 35 mm
darkroomenlargers has been to mount a longer focal lenght than
normally used. Instead of 50 mm a 60, 75 or 80 gives a better depth of
focus at the filmplane. It's more narrow at the "paperside" of the
lens like a camera with a longer lens – but larger on the other side.
Just look at a telelens; When focusing the lens moves much more in and
out from the filmplane than a wideangel......

Nikon might play with THAT in mind when building the next generation
of filmscanners. But I doubt that we will see a new generation in the
near future. It's amazing that Nikon haven't taken this as a problem
allready.

As for diffusers, it's not a solution for this problem. It is when it
comes to deal with the character of the harsh LEDs as a lightsource in
some ways perhaps. It would be better if we could get the sharpness
back than hiding the differences between sharp areas>>blurred..

nikita
 
K

Kennedy McEwen

Gary L said:
I don't know about the "weaker lightsource", but I do believe the scanner
lens is probably faster (i.e. less DOF), probably in order to speed up
scan times.

Nope, the lens is the same speed as the LS-4000. The LS-5000 is twice
as fast as its predecessor (20sec v's 38sec) because it uses a double
CCD - the same technique as the LS-8000 used for its high speed mode,
but with two lines instead of three. Hopefully it does not suffer from
the same mechanical resonance which made that (default!) option unusable
in the LS-8000.
 
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