Aperture Stop on a Nikon Ti-2

[Jeff Spector]

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Greetings,
     I'm working on setting up a system based around a Nikon Ti-2 body. For
reasons out of my control the system does not have the normal Nikon Lapp
adapters on the EPI port, but instead has sine non Nikon hardware attached
to it. The custom hardware has a mirror and an open port where I can attach
my lightsource. The issue is that I want to have ND filters, and more
importantly and Aperture stop in the EPI light path ( like the stock Nikon
hardware does). I think this can easily be accomplished with the use of a
4f lens system to relay the plane where I'd like the aperture to go (so we
can control the incident NA of the epi lamp). My question is what size
lenses to use,I think 1 or 2 inch lenses will work but I also think I need
to be aware of the magnification.  I'm not sure what is in the Nikon EPI
arm, but I don't think it is a 1x mag between the lamp and the objective.
If anybody knows this info, or has built their own  "epi illuminator"
please get back to me.
Thanks!
-Jeff

[Craig Brideau]

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Hi Jeff, I've tried this myself with a Ti-1 and I found you can get
considerable chromatic aberration depending on the lenses you use. If you
are working with filtered light with narrow bandwidth you will be OK, but
if you are working with polychromatic light or several widely-spaced colors
it can be problematic. I've actually used Nikon Tube Lenses as relay lenses
and it was... ok for narrow bandwidth light but terrible for poly.

Craig

On Wed, Jun 9, 2021 at 12:45 PM Jeff Spector <[hidden email]> wrote:

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> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Greetings,
>      I'm working on setting up a system based around a Nikon Ti-2 body. For
> reasons out of my control the system does not have the normal Nikon Lapp
> adapters on the EPI port, but instead has sine non Nikon hardware attached
> to it. The custom hardware has a mirror and an open port where I can attach
> my lightsource. The issue is that I want to have ND filters, and more
> importantly and Aperture stop in the EPI light path ( like the stock Nikon
> hardware does). I think this can easily be accomplished with the use of a
> 4f lens system to relay the plane where I'd like the aperture to go (so we
> can control the incident NA of the epi lamp). My question is what size
> lenses to use,I think 1 or 2 inch lenses will work but I also think I need
> to be aware of the magnification.  I'm not sure what is in the Nikon EPI
> arm, but I don't think it is a 1x mag between the lamp and the objective.
> If anybody knows this info, or has built their own  "epi illuminator"
> please get back to me.
> Thanks!
> -Jeff
>

[Zdenek Svindrych-2]

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Hi Jeff,

Short answer: 2 inch. Maybe more.

Long answer: well, depends what your light source is. You've mentioned a
"lamp", but today it's most often a fiber or liquid light guide, sometimes
LED directly.
A "4-f" relay is easy to design, but it's never used in commercial systems,
as it's bulky, especially if you want both aperture and field stops. Adding
extra lenses makes the illumination setup more compact.
Generally, shorter focal length lenses can be smaller. But how close to
your objective lens do you think you can get? In commercial systems the
closest lens is just outside the filter turret housing, but in a homemade
setup with lenses outside the microscope body you're at 300 mm, if not
more. A simple ray trace on a piece of paper will give you an idea how big
the lenses (achromatic doublets) need to be for a given field of view (or
rather 'field number') and numerical aperture.
Also, lower power lenses tend to perform better optically than the short
focal length ones. Depending on your setup (Koehler vs 'critical') you
still may need a high-power collimating lens right at the light source (a
condenser lens).
Btw, I'd estimate the magnification between the lamp and the objective lens
around 5x for arc lamp setups.

Best, zdenek

On Wed, Jun 9, 2021 at 2:45 PM Jeff Spector <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Greetings,
>      I'm working on setting up a system based around a Nikon Ti-2 body. For
> reasons out of my control the system does not have the normal Nikon Lapp
> adapters on the EPI port, but instead has sine non Nikon hardware attached
> to it. The custom hardware has a mirror and an open port where I can attach
> my lightsource. The issue is that I want to have ND filters, and more
> importantly and Aperture stop in the EPI light path ( like the stock Nikon
> hardware does). I think this can easily be accomplished with the use of a
> 4f lens system to relay the plane where I'd like the aperture to go (so we
> can control the incident NA of the epi lamp). My question is what size
> lenses to use,I think 1 or 2 inch lenses will work but I also think I need
> to be aware of the magnification.  I'm not sure what is in the Nikon EPI
> arm, but I don't think it is a 1x mag between the lamp and the objective.
> If anybody knows this info, or has built their own  "epi illuminator"
> please get back to me.
> Thanks!
> -Jeff
>

--
--
Zdenek Svindrych, Ph.D.
Research Scientist - Microscopy Imaging Specialist
Department of Biochemistry and Cell Biology
Geisel School of Medicine at Dartmouth