995 CoolPix Shoot Out
Red arrows show artifact caused by spun cast lens. It is much more
noticeable than in the 995 then the 990 but it is there in the 990.
Olson & Gordon Couger
December 4, 2002
updated May 30, 2005
This originally was about image processing artifacts but the
has developed more about the ring artifact that is present in many
camera but most often reported in the CoolPix 995 and newer when used
on compound microscopes using Kohler illumination.
The artifacts are worst on light backgrounds. If the image has much
strong detail the artifacts will not be nearly as objectionable.
The artifacts can be completely avoided by not using any zoom at
Arron Messing has reported that CoolPix 5000 with the adapter for the
slide copier does not exhibit any artifacts. Several others have
confirmed that. I have had one person say they get artifacts with
the 5000. GC 5/30/05
The images have not been enhanced in any way or corrected for color
they are as shot if you double click on them you will get full res
This change in the image from what I see in the monitor is sometime
very noticeable when it switches from the saved image to the monitor
image. To be fair there are times the picture is improved but many less
are improved than are damaged.
Your own conclusions.
would like to thank Gregor Overney
for the picture of the optimized
artifact taken using a relay lens.
That the CoolPix 995 has a lens artifact is quite commonly known.
so do all digital cameras that have a non-removable zoom-lens. The
worse for the 995 than the 990 since the number of lenses in the zoom
increased.While interference patterns of the SONY DSC-S70 are
different, they do
exist as well.
All digital cameras with non-removable zoom lenses might show this kind
problem. It's not specific to CoolPix. I have attached an image I took
with a 995. I tried to "optimize" the appearance of the problems.
Therefore the problems appear to be overemphasized. -Gregor
March 18, 2003
Further work has shown that proper alignment of the condenser and
of the microscope and proper Kohler lighting so no stray or off axis
enters the microscope reduces the artifacts to a degree. If the image
texture or strength it is usually enough to make them
They can be eliminated by setting the focal length to 8.2mm with
and focused at infinity. This wastes a good deal of resolution but
there seem to
be no artifacts that show up at these setting on my scopes. Here is an
unenhanced full frame example of some skin cells scraped from my foot
mounted in immersion oil taken with a 40x .65 objective with Mark
eyepiece adapter on a Nachet 300 in DIC mode. Using the best
could set up. The brown spots are athletes foot fungus. This is the
best image I
in regards to artifacts that I have been able to get to date. The
is a diatom. Neither has any hint of artifacts that I can find.
a some spots of dirt on the condenser common to to both images. The
no diffusion in the Kohler light system and show every fault in the
system. That is one of the reasons I use it in these tests. GC
June 16, 2003
Gordon Couger 5/30/05
Many reasons have been put forth for the cause of the artifacts in
Nikon CoolPix cameras. After many many hours of testing
none of them explain the problems I see to my satisfaction. Considering
that projected image from the microscope is in focus from any
point from the surface of the eyepiece to infinity any
disturbance in the rays of the image as it passes through the camera
lens will show up in the image. The fact that it only shows up in
transited light microscopes causes me some real concern about
making any generalized statements as to the cause of the artifacts.
Form the many hundred images I have taken and been sent by others I
have see reflections, refraction, hot spots as well as the blobs, rings
and central artifact..
Now at the end of May in 2005 after 2.5 years No one has
come out with a really good consumer camera for a microscope. The small
lens sized of the CoolPix 990, 995, 4500, 5000 and 5500 make an easy
match to a microscope. In many cases the eyepiece of the microscope
works better then the most expensive modern relay lens. Ted Clark gets
full field with a Olympus 8X WHK eyepiece and a high eye
point 10x Zeiss Kpl 20 mm FN and CoolPix 995. Both eyepieces are part
of the correction in the optical train and using modern digital
adapters will show chromic aberration in outer third or forth
It is well known that the CoolPix 990 has minimal ring artifact that
have worked well for every one that uses it is 3.34 mega pixel camera
and sells used for $100 to $200 dollars. It will produce images
good enough for publication in journals.
Arron Messing has been using the CoolPix 5000 with no artifacts
problems. It will use the same hardware as a the CoolPix 990,
995, & 4500. The CoolPix 5000 sells for $250 to $300 used. If
I had to buy something today this is what I would get.
Hopefully a better camera will emerge that will adapt to a microscope
but right now the CoolPix 990 and 500 are probably the 2 best choices
for someone that doesn't want to go the digital SLR route.
The well known and stable feature set, the ease they connect to a
microscope and their history of reliability and longevity are hard to
For the money buying a camera for a microscope I think a dedicated
camera for a microscope makes more sense that dSLR. I would only
put a dSLR on a microscope if I was buying one for some other reason.
Just as SLR camera are not good fits for microscope neither are dSLR
cameras. When I want high resolution images I use a CoolPix 995
to compose the shot and determine the exposure and then use a 35
mm microscope camera.
Some people are havening good results with digital SLR camera on
microscope. Jan Hinsch wrote About the
use of Digital Single Lens Reflex Camera on Microscopes for the McCrone Group's Modern Microscopy.
If you decide to go this route be sure the camera has a mirror lock up,
a way to view the image with the mirror locked up and meters the light
with out a lens. Some Canon users are very happy with the low light
performance of the CMOS sensor Canon uses. Be aware the Canon
Rebel does not have mirror lock up feature.
The adapter makes no difference. I have not determining the
cause of the rings to a point that I can say with any certainty
anything but they get worse as you increase the zoom and that they are
inherit to the Coolpix 995 through 4500 and the lighting
not anything added in between. I suspect that the rings and blobs are
artifacts caused by internal refection of tooling marks or something.
It is contestant over a long period of time from 995 thou
4500. The Coolpix 5000 and 5400 do not have the artifacts I
documented. I believe that everything I know about a 5000 applies to a
5400 everthing I read leads to believe that. I would check and be sure
that you can't crash the lens into the eyepiece with the zoom of the
movable lens in case it is differs the than the 5000.
All cameras with lens in the path between the eyepiece and the sensor
or film have the potential to distort the image to some degree.
I have built a number of parts to mount my Coolpix 995 to a Zeiss
dovetail that goes in the camera
pot and I almost always use Mark Simmons' adapter with my on
Leitz and Zeiss objectives. A Nikon Art.Nr UR-E6 is need
with a CoolPix 5000 & 5400 that cost less than 10 dollars
most solutions such as Mark's adapter for CoolPix camera used on
microscopes at Perspective Image www.perspectiveimage.com/1/nikon.php
It has been report that artifacts are absent in images made by late
4500's. I have not seen any pictures taken by late run 4500's. But
certain conditions must be met to make the rings show up so the people
reporting them may or my not have thing right to produce them. The
better the lighting on transmitted light microscope is the better they
show as the depth of focus increases to include the light path above
the first lens in the eyepiece near the subject and below the
first lens near the subject in the condenser. When
this condition is reached every speck of dust show up in the image.
This not the same as depth of field which for a microscope is very
small and is inversely proportional to the size of the numeric aperture
of the entire microscope.
To get the best solution for a CoolPix has an artifact problem as
the ones shown above is to use an adapter/relay lens/eyepiece that
fills the field with the largest image possible. In my expertise there
are no artifacts the widest angle setting of the zoom lens on a CoolPix
995 or 4500. For my testing I use a Nachet 300 DIC transmitted
light scope that I believe to be one of the best scope possible to show
lens artifacts or any problem in the light train. It has true Koehler
lighting with no diffusion in the light train and the DIC color
gradient with out a green filter really high lights any problem.
The second choice is digitally removing the artifacts. It also has the
effect of correcting for uneven lighting, a dirty condenser or anything
else on the slide used to subtract out the artifacts and the back
ground. I believe that this can be automated in ImageJ a public domain Java
program from the National Health Service that has a script language and
program plug in interface. There is an active programming and
users group that will help you with problems. A much better solution
than in most paint programs.
To the best of my memory to digitally remove the artifacts shoot an
image of a blank slide with the mountant and cover slip a near the
subject as you can get, save the as subject-bl.tif. The to what ever
you have to do to it make a smooth even background and save it as
subject-bk.tif. It may just take heavy low pass filters or it may
take hand editing. Then take the picture of the subject and save it as
subject-m.tif an write protect it and make back ups of all 3 files in
at least 2 other places at lest one off premises. I upload mine to my
server and when I was working took a back up ever week to an off site
fire poof safe.
Then copy subject-m.tif to subject-mw.tif use the ImagJ image math tool
differencing to remove subject-bl.tif from subject-mw.tif and save
subject-dif.tif and save. You may have to go to Paint Shop Pro or
Photoshop at that this point to make background with subject-bl.tif and
over lay subject-mw.tif
I have only worked this out on monochrome images. So you may have
to split the stack into R, G & N or C, M & Y stack and process
each one separately but once a scrip is written for it is will only
take a time to run. But I am on another project at the moment but I
would be gad to help anyone with the problem.
Today I have a Coolpix 995, several Zeiss 35 mm cameras and Leitz
4X5 for a microscope. For high quality I would use the 995 as a light
meter and use film. If I was in a hurry I would use 4X5 and contact
print the negative or scan them directly in with a scanner or possibly
try using the 995 to scan the negative on a light table and try to get
the best of both worlds using black and white film and a set of red,
green and blue filters I have.
If you do this on images for publication I would make copies of every
step and the complete environment that did the work including a full
copy of installation of Imagej and all its plugins and the copy of Java
runtime in use and zip it up and put in escrow with a third party with
an unimpeachable reputation and make the whole package available to the
readers as well via a web site so anyone with a question about your
methods could see for them selves what you did it. This is a good piece
on the ethics of image processing By the Pharmacy
Department at Arizona University Digital
Image Ethics The example I just described is a
very extreme one case of image processing and at the least the original
should be the origninal should be easily availble to the reader.
If I were buying a digital camera just for use on a microscope today. I
would choose from one of these three. A Coolpix 990 with the 3.3
mega pixels and a zoom that only cause the faintest hint of rings that
are extremely difficult to see and cost from $120 to $200 on the used
market. A 990 will capture all there is to see in a microscope
and the articulated head makes a fantastic field microscope an
often over looked feature of the Coolpix 600/950 thru 4500 series.
Aaron Messing continual praises of the 5 mega pixel
Coolpix 5000. Aaron has the credentials to have a opinion that counts
on microscope cameras an "aaron messing" "nikon small world"
search on Google brings up 61 hits. The 5000 cost $200 to $300
used on ebay and needs Nikon UR-E6 step down adapter
to make fit 28 mm Coolpix accessories. I wouln't buy Nikon's
high priced relay lens. I use sometingh tht uses the eye piece that
matchs the microsope objects or Mark Simmons adapter perspectiveimage
He desiged, makes and tests it himself. He runs a small low over head
business and when you talk to some there it is Mark and he does not
make extravagant claims about his product. He is straight forward about
the problems with chromatic aberration of older Zeiss, Lomo, Leitz and
Olympus microscopes. I can show you images that look bad but in reality
it is small problem in most cases as the aberrations are most
noticeable in the outer 1/3 of the image and the feature must be shown
in both red and blue light not red or blue light as most features are.
If you are using the microscope for measurement and using colored light
this would be a serious concern but most images are cropped to a
square image from a round image made by the eyepiece so only the 4
corners present a problem.
If chromatic aberration is a problem then the only choice is to use an
eyepieces that matches the objectives. I have built a number of parts
to mount my Coolpix 995 to a Zeiss dovetail that goes in the camera
pot and I almost always use Mark's on Leitz and Zeiss
Spike Walker needs no intodtion in photomicroscopy. Spike's work says
it all. Spike has gone from the Coolpix 5000 to a Sony W7 for a small
digital camera. Spike has a small fortune in camera equipment. I am not
sure if he became a professional photographer to make money or to try
to pay for his obsession. Ether way the we are better off for both
Spike and Aaron's experience and their stunning images. Even though at
times they had to beat me about the head a bit to get me to
listen. At 7.1 mega pixels the W7 the $400 camera and $225 for an
adapter is much less than I paid for the Coolpix 995 to get in the
game. In private correspondence Spike has convenience to take a very
hard look a the W7 before I buy another camera. If I was starting form
scratch I am fairly sure it would get the nod over anything but a good
deal on Coolpix 990 if I was trying to get by on the cheap.
All of this bring up how many pixels is enough. In the McCrone
Group's Modern Microscopy Ted Clarke's shows that for capturing data 2
mega pixels will do www.modernmicroscopy.com/main.asp?article=31
and Nikon U puts it 2.2 Mega pixels for a 0.5x image and 617 pixels for
100x 1.4 n.a. objective at
http://www.microscopyu.com/tutorials/flash/pixelcalc/ with a bit more
user friendly interface.
So for a microscope what good are the extra pixels. They determine the
size the image can be printed. While 617 pixels gets al the data on
1400x image it makes lousy 4x5 print.
Here is a scanning calculate http://www.scantips.com/calc.html to find
the various resolution to scan film for the resolution you need.
Magazines use 300 dots per inch dpi, news papers use 60 to 75 dpi and
photographic prints use 240 to 400 dpi and I believe JPGs and
printer's magic software relaxes that to some degree. But you don't get
to cheat at the print shot that uses halftones and ink on paper. I have
been there, done that and it took 5 years to get the ink out from under
my finger nails.
Here is a simple table
on the Lulu Blog
showing 8 mega pixels needed for a 300 dpi 8x10 page. That's why the
commercial buyer want slides or very large digital images as a 36 x 24
inch photo quality poster takes at lest a 223 megabyte image.
I think this shows if one is serious about selling ones work the
digitally age is not truly here yet. Using a 3 to 7 mega pixels camera
to do small images and use it to set up shots for film caners is
going to be the way to work. Unfortunately the market for microscope
images is small.
Now the down side if I have my math right is an operation that takes 10
seconds on 3.2 megabyte image 223 megabyte image takes 180 days on 223
megabyte image not counting swapping out to disk. The same 10 second
operation on a 3.1 mega pixel image takes 3 minutes and 15 seconds on a
7.1 mega pixel image. So the bigger the image the faster the computer,
video card and monitor you need. While Moore's law seems to still hold
that the speed of computers are doubling and the size of chips grows
smaller when the number of operations is the time it took at the old
sizes raised to the power of the new size divided by the old size large
numbers being anything to molasses like slow crawl. <10/12/2004>