Hi folks,

I'm thinking about buying a microscope. I have several old microscopes
in various states of disrepair, which I got for nothing. But I've wanted
a reflected light microscope for a while. I've seen a Watson "Standard
Metallurgical" reflected light microscope for sale pretty cheap. I
already have a bunch of Watson spares, so it looks like a tempting buy.

However, I don't know much about microscopes, and various issues are
confusing me. So I'm hoping people here might be able to help.

* I have lots of Watson lenses with an RMS thread. These came from a
school and were used on transmitted light microscopes. As far as I know,
the lenses I've got and the microscope I've seen for sale both use
lenses designed for a fixed tube length, not infinity-corrected lenses.
So can I use my spare Watson lenses on a reflected light microscope, or
do I need special lenses designed for use with reflected light?

* Presumably there's no way of using infinity-corrected lenses with a
microscope intended to have a fixed tube length? I've read that the
infinity-corrected microscopes have an extra lens in the tube somewhere.

* The microscope I'm thinking of buying doesn't have a nosepiece which
carries multiple lenses. However, I have several spare Watson
nosepieces, and shorter drawtubes to accompany them. I tried them out
this afternoon. Now my understanding is that when you use the nosepiece,
you should be able to fcous using a low power objective lens, then
switch to a high power objective and find that everything is still in
focus. It doesn't seem to work, even with lenses from the same
manufacturer. I always have to correct the focusing after switching
lenses. Is my understanding wrong, or does the microscope I'm using need
adjusting somehow?

* I want a low power combination of lenses. Watson don't seem to have
manufactured an objective below x2.5 and an eyepiece below x5. I'd like
to go lower than this. Olympus manufactured a x1.3, but it's intended
for a microscope with a 200 mm tube length. The Watson microscopes can
be extended to 200 mm tube length, but it clearly isn't their normal
setting. What would happen if I tried to use an Olympus lens with a
shorter tube length? Would I just get a different magnification and
focusing distance, or would everything get royally screwed up? I think
the Watson microscopes have a default tube length of 160 mm, but it
appears to be adjustable from 155 to 220 mm with the nosepiece fitted.

Does anyone have any advice or thoughts? Is this a good idea?
Suggestions would be appreciated.

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Hi folks,

I'm thinking about buying a microscope.

Not an expert, but have spent many hours hunched over them peering at
microstructures, trying to make sense of what I see. ("Is that Martensite,
or just lots of scratches?")

I can't intelligently comment on your specific queries re the Watson gear,
but am happy to relate some experiences.

I've always used, with mixed, (but usually reasonable) success, a variety of
inexpensive reflected light microscopes and would like to share some nice
features.

* light source must be variable, preferably continuously, else it will
always be too bright or too dark.

* focus mechanism tightness must be adjustable (or tight enough) to avoid
creep under gravity. I had one 'scope which would allow the objective lens
to gradually settle down onto the specimen (!). I forget if it was an easy
adjust.

* facility to accept polarising filters. Can help.

* I've only ever used mono 'scopes, but binocular would be nice - trinocular
even nicer if you are planning photography. Mono will do, 'though. ($$$)

* a nice micrometer-adjustable (smooth and backlash-free) X/Y platform on
the stage makes viewing much more comfortable. (Do all 'scopes have this
nowadays?)

If buying secondhand, look for all the obvious things (smoothness of focus
etc) and don't forget to look for fungus in the optics.

Most of the ones I've used have been no-named beasts made (I think) in
Czechoslovakia, mingled with a few Olympus (nice) ones. None of them were
hideously expensive, and a good one will last forever, treated properly.
Lash out and spend more than you want to. You won't regret it, and neither
will your heirs.

--
Jeff R.

FWIW, I sold the body of such a transmitted light microscope on ebay last
year - it went for ten or twenty dollars, and I shipped it internationally -
shippng was more than the auction price - so if you have lenses, you should
look and see if someone else finds a body without lenses



--
Posted via a free Usenet account from http://www.teranews.com

Christopher Tidy wrote:
Hi folks,

I'm thinking about buying a microscope. I have several old microscopes
in various states of disrepair, which I got for nothing. But I've wanted
a reflected light microscope for a while. I've seen a Watson "Standard
Metallurgical" reflected light microscope for sale pretty cheap. I
already have a bunch of Watson spares, so it looks like a tempting buy.

However, I don't know much about microscopes, and various issues are
confusing me. So I'm hoping people here might be able to help.

[snip]

Best wishes,

Chris

I won't get into addressing your specifics, as I only have 2 reflected
light microscopes (one is a polarising scope used for petrographic work,
the other for looking at surface defects via Nomarski DIC). However,
your best bet is to post your questions on sci.techniques.microscopy.
There are several knowledgeable folks who will help. Some will assume
you have an unlimited budget, though! Several are hobbyists, so are
aware of the constraints of the purse.

The short answer about the infinity-corrected objectives is that they
will not work with a fixed-length stand, because, as you noted, there is
an intermediate lens required in the infinity system.

Check out: http://microscopy.fsu.edu/primer/index.html
http://www.microscopyu.com/sitemap.html
for *lots* of excellent tutorials, and:
http://www.microscopy-uk.org.uk/mag/indexmag.html

for other good stuff microscopically.

Welcome to another fun world of adventure and (most importantly) toys,
er, uh, tools.

Joe

William Noble wrote:
FWIW, I sold the body of such a transmitted light microscope on ebay last
year - it went for ten or twenty dollars, and I shipped it internationally -
shippng was more than the auction price - so if you have lenses, you should
look and see if someone else finds a body without lenses.

Indeed. There seem to be a lot of exceptional instruments going at very
low prices at the moment.

Best wishes,

Chris

Jeff R. wrote:
"Christopher Tidy" wrote in message
...

Hi folks,

I'm thinking about buying a microscope.


Not an expert, but have spent many hours hunched over them peering at
microstructures, trying to make sense of what I see. ("Is that Martensite,
or just lots of scratches?")

I can't intelligently comment on your specific queries re the Watson gear,
but am happy to relate some experiences.

I've always used, with mixed, (but usually reasonable) success, a variety of
inexpensive reflected light microscopes and would like to share some nice
features.

* light source must be variable, preferably continuously, else it will
always be too bright or too dark.

* focus mechanism tightness must be adjustable (or tight enough) to avoid
creep under gravity. I had one 'scope which would allow the objective lens
to gradually settle down onto the specimen (!). I forget if it was an easy
adjust.

* facility to accept polarising filters. Can help.

* I've only ever used mono 'scopes, but binocular would be nice - trinocular
even nicer if you are planning photography. Mono will do, 'though. ($$$)

* a nice micrometer-adjustable (smooth and backlash-free) X/Y platform on
the stage makes viewing much more comfortable. (Do all 'scopes have this
nowadays?)

If buying secondhand, look for all the obvious things (smoothness of focus
etc) and don't forget to look for fungus in the optics.

Thanks very much for all that useful advice, Jeff.

Most of the ones I've used have been no-named beasts made (I think) in
Czechoslovakia, mingled with a few Olympus (nice) ones. None of them were
hideously expensive, and a good one will last forever, treated properly.
Lash out and spend more than you want to. You won't regret it, and neither
will your heirs.

I'm on a budget, but as a philosophy I definitely believe in investing
in good equipment and tools. You get what you pay for.

Best wishes,

Chris

Joe wrote:

snip

The short answer about the infinity-corrected objectives is that they
will not work with a fixed-length stand, because, as you noted, there is
an intermediate lens required in the infinity system.

Thanks for clarifying that, Joe.

Welcome to another fun world of adventure and (most importantly) toys,
er, uh, tools.

:-)

Best wishes,

Chris

Christopher Tidy wrote:
Hi folks,

I'm thinking about buying a microscope. I have several old microscopes
in various states of disrepair, which I got for nothing. But I've wanted
a reflected light microscope for a while. I've seen a Watson "Standard
Metallurgical" reflected light microscope for sale pretty cheap. I
already have a bunch of Watson spares, so it looks like a tempting buy.
What are you going to do with this microscope? I use a couple
stereo zoom microscopes (Bausch & Lomb and Olympus) for all
manner of work. But, then I am examining 3-D objects, not
surfaces, as in metallurgical work. I use it mostly for
micro-soldering and examination of soldered SMT parts, but also
for other things.

Jon