[meteorite-list] First attempt at photographing thin sections

[Starsinthedirt at aol.com]

Hi Dave and list.  I often work with  circular polarizers as well as linier 
polarizers.  Not to mention full and  1/4 wave retardation filters.

Don't avoid the circular polarizers.   When you invert them they function 
as a linier polarizer.  My main Xpol  scope (An aus Jena Fluoval) has SunPack 
Circular polarizers on it right now and  they are a quality camera filter 
that can be found (often quite cheep in odd  sizes) on eBay.

For extreme extinction (black when full crossed  transmitted light is 
viewed) like what is needed for subtle changes in  reflectance viewed in incident 
light.  I use a Glan/Thopson style mined  calcite prism polarizer.  

I use this technique on an aus Jena  Neophot.  The Gold Basin image set on 
my micrograph gallery shows off this  effect well.  Please check it out.  
The results are quite unlike any  thing most people are accustomed to.  

http://www.meteorite.com/meteorite-gallery/articles/gold_basin/

Any  polarizers are useful.  I have even used the filters striped out of 
non  functioning Sony PS3 disk readers.  I wrote a Meteorite Times article on  
that.

The film polarizers are a great start but they distort the image  when used 
in the analyzer position.

Tom



In a message dated  10/5/2010 11:29:31 A.M. Mountain Daylight Time, 
dfpens01 at yahoo.com  writes:
Nice job, Richard.

I understand that one should only use  linear polarizers and that most 
camera polarizers are circular.  So, be  careful with what you use.

Perhaps Tom Phillips can shed some light on  the differences in polarizers.

Dave 

--- On Tue, 10/5/10, Richard  Kowalski <damoclid at yahoo.com> wrote:

> From: Richard Kowalski  <damoclid at yahoo.com>
> Subject: [meteorite-list] First attempt at  photographing thin sections
> To: "meteorite list"  <meteorite-list at meteoritecentral.com>
> Date: Tuesday, October 5,  2010, 6:01 AM
> I had some free time tonight so I cut
> a few pieces  of some plastic polarizing filter I had and
> used them on our biological  microscope. I had picked up a
> few low priced thin sections at this past  year's Tucson
> shows. For a first ever attempt at photographing  thin
> sections in cross polarized light, I think I've done an ok.
>  job.
> 
> I've uploaded my first 5 to an album on Facebook. Below  is
> a link that should be accessible even if you don't have a FB
>  account.
> 
> http://tinyurl.com/27uj6tk
> 
> I haven't  yet calibrated my field of view yet, so at the
> moment I can't offer the  scale of the features in the
> images. Sorry.
> 
> I'd  appreciate any tips or advice the experts are willing
> offer to help make  future images better.
> 
> Thanks
> 
> --
>  Richard Kowalski
> Full Moon Photography
> IMCA #1081
>  
> 
>       
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