Natural Science Forum / Physics / Optics / November 2004

Ale,  You can't get the whole field since your trying to take a rectangle
out of a circle.  If you decrease the power of the photo eyepiece that would
help.

Kevin

Ale,

You could ask your local Zeiss rep whether they have a
c-mount adapter with a different magnification (typical is
0.5x, I think).

Or you go directly to Thales-Optem and choose a c-mount with
an appropriate fixed magnification or with a zoom.

http://www.thales-optem.com/videocouplers.html

Cheers,

Franco

Hi Ale,

I agree with Franco.  The problem is just a mismatch between the size of the
camera chip and the magnification of the C-mount adapter.  Your Zeiss dealer
should be able to help.

For a 1/2" CCD chip, you need a C-mount adapter with 0.5X magnification factor.


If you have a 0.63X c-mount adapter, the image will be slightly magnified, and
if you have a 1.0X C-mount adapter, the image will be *greatly* magnified.

Some of the 1.0X C-mounts will not have any lenses in them...they are just
"straight-through" metal tubes.  Take a look inside the adapter.  If you see no
lenses in it at all, that's a sure indication that you have a 1.0X adapter.

Replacing the adapter with one that's 0.5X will solve your problem.

Best,

Bob Chiovetti

You have alredy been given the answer in short form. The output of the
microscope is larger than the chip size.  You need a reducing lens in
the c-mount to focus a larger portion of the output of the microscope
onto the chip.  

What has not been indicated is that your current setup produces
unintended empty magnification.  The empty magnification occurs
because a small portion of the microscope image is captured on the
chip and then is expanded digitally beyond the abiltiy of the
objective.  Condiser that the 1X c-mount is designed for a 1"
(diagonal) CCD chip.  With a 0.5" chip only 25% of the information
falls on the chip..  Thus the unintended magnification factor is 4X
It is analgous to using a 40X eyepiece or an additional 4X digital
zoom to enlarge the image.  The image is large but the information is
limited.  

Aaron    

I just sent out a post for a similar request to nikonians.org. Here's the
link. I think the document mentioned there will help you in finding the
right combination of adapter and photo relay lens.

http://www.nikonians.org/dcforum/DCForumID63/568.html

Gregor

The Zeiss needs .67X or .66X phototube.

Gary Gaugler, Ph.D.
Microtechnics, Inc.
Granite Bay, CA 95746
916.791.8191
gary@microtechnics dot com

Are there any optics in your adapter ? If not then you need a 0.5x or .63x
adapter which you can get from Zeiss.

Regards

Chris