Re: Digital Reflex on microscope

From: Aaron (nghy_at_comcast.net)
Date: 06/23/04 

Date: 23 Jun 2004 17:22:42 -0500

Hello,

The Nikon D100 SLR is not suited for this application. The Coolpix
990, 995, 4500, and 5000 all can be adapted with a simple eyepiece
relay lens adapter. That is what your friend had.

Most cameras (film or CCD) having a standard fixed lens will work with
an eyepiece adapter. Since the trinocular port is equivalent to either
of the tubes that you normally look through everything is close to the
same focus.. You can chose to install a lens on your D100 and move it
very close to the eyepiece or you will need a much different setup.

To adapt a SLR camera (without the front lens installed) on the
microscope requires a special projection eyepiece which focuses the
image on the CCD directly. This projedction eyepiece is chosen so that
the image is adjusted for the film size. A CCD chip is much smaller
than any film system. Your relay lens needs to reduce the image size
to the size of the CCD. Without the reduction, only the center of
the image will fall on the CCD. That is why you get the unintended
extra magnification

Even with the older film cameras a special focusing system was used
that split the image going to the film .Part of the image was focused
on a ground glass plate that was optically equivalent in distance to
the film. A special eyepiece was used to view the image projected on
the grould glass screen.

You need to consult a book on the subject. I recommend "Photography
with a Micorscope" by Fred Rost and Ron Oldfield. It is an expensive
book but it clearly illustrates the problems and the solutions.

Aaron. .

 

On 23 Jun 2004 02:45:35 -0700, f.malfatto@fmal.com (Fulvio Malfatto)
wrote:

>I'm very happy with my digital SLR Nikon D100, and now I would like to
>use it also to whit my Optika SZM2 microscope (stereo trinocular 7-45x
>zoom - 10x23 oculars).
>[ http://www.optikamicroscopes.com ]
>
>I buyed the scope adapter, the M-ring, and everything if fine at
>mechanical level, but the photos are very poor.
>My problem are these :
>1) The 1.5x focal lenght done by digital CCD brings me to a too high
>magnification, so I can't have the same field I see in oculars, but a
>smaller one.
>2) Focusing is very difficult, and is different from the one I choose
>on oculars : the third eye requires a totally different adjustment, so
>I loose the utility of the third eye. ( I tried every possible tuning
>of the scope adapter and moved the camera as far as possible from
>ocular. Parfocality is correct if I look, but not when I shoot)
>3) The light is so low also when I use fiber illuminators, that I
>can't see the item in the eyepiece of the camera, so focusing is done
>by doing multiples photos at different positions.
>
>I normally shoot my photos whit camera well fixed on the microscope,
>and controlling it from pc by the nikon capture software, so i'm sure
>to avoid any vibration or shooting problems (mirror lock-up is
>applied), but in few months i never had a good photo : out of
>focus,color diffraction, etc.
>Then a friend of mine came with his coolpix 990, just put it on
>already focused ocular, and shooted : he had a quite nice shoot, whit
>a good DOF and surprisingly well focused, in few word, the same thing
>my eye sees in oculars. How it is possible ?
>
>So I ask to some expert : where am I wrong ? I am very disappointed I
>can't couple a such expensive set of tools.
>The photocamera is the best one I ever had, I use it in macro with
>Nikkor 60 mm and is really great up to 2x.
>
>Also the microscope is quite good, it is not as expensive as the
>camera is, but is very effective in the normal use. How can I test it
>to be sure it is able to do the job?
>If I change the third eye ocular from 10x to 5x (better would be 6.6x)
>can I have the same field on camera ?
>
>Is there any thing I can do to improve my photos?
>Any suggestion is welcome.
>Thanks in advance
>Fulvio

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