January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 10:56 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 13 posts ] 
Author Message
 Post subject: Polarized filter on the microscope
PostPosted: Sat Dec 21, 2013 11:17 pm 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 3:45 pm
Posts: 289
Good evening,

On the Forum, I have found an interesting article on how to transform your microscope in a polariscope: http://www.gemologyonline.com/LaShawn/L ... Filter.pdf.

I would like to know if the quality of the polarized lenses is important. I looked on internet and there is $11.00 lense(Vivitar) to $200.00. Of course, that last price mutiply by two is out of my budget. But I can give more than $22.00 for that.

I was also curious to know if there are advantages and disadvantages for using the microscope as a polariscope.

Do you have advice for that method?

Thank you.

Good night

Brigitte


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Sun Dec 22, 2013 2:57 pm 
Offline
Site Admin

Joined: Thu Jan 05, 2006 4:27 pm
Posts: 1750
Hi Brigitte,

You can make a polariscope out of any linear polarising filter. Check edmundson scientific they used to sell the stuff in sheets and you can easily cut two shapes.

Dr Hanneman also sells a polariscope which consists of two squares of polarising filter which fit into notches on a plastic stick,,,This fits quite well onto a microscope stage.

My own personal favourite is the small folding polariscope made by Gem-a This sits easily on the microscope stage and folds away after use taking up hardly any space at all.

None of the above solutions would cost much (certainly nowhere near 200 bucks)


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Sun Dec 22, 2013 2:59 pm 
Offline
Site Admin

Joined: Thu Jan 05, 2006 4:27 pm
Posts: 1750
I never addressed your question about using the polariscope with the microscope. I would heartily recommend it...by rotating the stone you can check double refraction in inclusions and sometimes you find the most beautiful rainbow of colurs imaginable...go play


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Sun Dec 22, 2013 4:27 pm 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 3:45 pm
Posts: 289
Good afternoon,

Thank you for your advices.

I have already monsieur Hanneman polariscope. I was not sure that I could use it as the polarized sheet would becomedurty by the stuff used to put in under the microscope objectives. But I will do that. :)

I do not have yet the microscope as it is my husband's christmas gift. Like my children, I have to wait.

So you reommand it. Do you think that it can replace a regular polariscope?

Brigitte


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Sun Dec 22, 2013 5:30 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
I recently was looking for some 40.5 mm linear polarizing filters (make sure any camera polarizing filters are labeled PL not C-PL which are circular polarizers for digital cameras that don't like regular pol filters. VERY important.)

I found some on ebay for a very low price. Like $2.95 each.
Their quality is just fine.
It is normally a waste of money to spend a fortune on such filters. Even the expensive ones consist of a plastic pol filter laminated between two layers of glass.

http://www.ebay.com/itm/BK-2-Filter-40- ... _704wt_888

40.5mm fits Jeff Wildmans refractometers and his gemscopes. He was out and bought some of the same ones. Not the above auction. The quality was fine. Came from Hong Kong.


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Sun Dec 22, 2013 8:35 pm 
Offline
Valued Contributor
User avatar

Joined: Sun Jul 15, 2012 6:29 pm
Posts: 321
Location: Los Angeles, CA
Depending on your microscope, you can add a (linear) polarizer directly to the scope. check the mm size of your microscope threading and buy a cheap cheap filter on ebay.
yours may look different than this, but if there are threads, it will work.
this has worked for many of my friends.
(wow, i need to clean my lens)
Image

then you can just use another very cheap filter and lay it over your well light.
Image

i understand that this is not a VERY quick thing to take on and off of the scope, but really, i find that it's fine to keep it on there most of the time.


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Mon Dec 23, 2013 1:26 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
Danny , what is with the two channels being different lengths. I would worry about THAT alot more than cleanliness.


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Mon Dec 23, 2013 3:52 pm 
Offline
Valued Contributor
User avatar

Joined: Sun Jul 15, 2012 6:29 pm
Posts: 321
Location: Los Angeles, CA
I thought it was the angle of the photo. :?
I'll check tomorrow when I'm back at the office.


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Tue Dec 24, 2013 1:24 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
The thing to check is that the two ocular tubes are matched as closely as possible. It may be a factory adjustment that turned out to look like that but I can't recall ever seeing one that asymmetric on a healthy scope.


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Tue Dec 24, 2013 3:46 pm 
Offline
Valued Contributor
User avatar

Joined: Sun Jul 15, 2012 6:29 pm
Posts: 321
Location: Los Angeles, CA
i tried to get a very straight-on picture.
they're aligned, it was just a wonky photo at first.
it's a meiji emz-5
Image


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Tue Dec 24, 2013 6:21 pm 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 3:45 pm
Posts: 289
Good evening

Thank you for your advices. I will look at that more closely during my vacation.

Merry Christmas to all of you
Joyeux Noël!

Brigitte


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Wed Dec 25, 2013 2:01 pm 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 3:45 pm
Posts: 289
Good day everyone,

I tried the eBay link given before but I can not have it from Canada. Too bad. The cheapest one I have found for that diameter( and they are LP) are $aroud $20.00. Not to bad.

If I understand well, I will be able to tunr one of the filter on the objective part of my vintage microscope GIA. If it is that, it is cool.

I appreciate to know that they were 2 kinds of polarized filters. Good to know.


Thanks

Brigitte


Top
 Profile  
Reply with quote  
 Post subject: Re: Polarized filter on the microscope
PostPosted: Tue Jan 28, 2014 12:51 pm 
Offline
New to the Forum or The Quiet Type

Joined: Sat Jan 25, 2014 9:36 am
Posts: 10
i have not tried on a Stereoscope yet, but I have good polarized results on compound and invert microscopes using the "lens" from movie theater's 3D glasses that I had laying around the house (sometimes I'm able to pick up a few of them off the ground from my neighborhood movie theater parking lot!)

The plastic lens/film just pop right off the frame if you twist it hard enough, and they can be cut to sizes. And yes, they need to be aligned with correct rotation and SIDE to produce the right effect.

Regards,


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 10 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock