Citric Acid

Olympusman · Post by **Olympusman** » Fri Feb 13, 2015 11:01 am

Citric Acid

I thought you might enjoy the label on the bottle.

rcroning · Post by **rcroning** » Sat Feb 14, 2015 7:03 am

Excellent! Were these photographed in cross-polarized light? Would you share some of your process?

Olympusman · Post by **Olympusman** » Sat Feb 14, 2015 10:21 am

Yes, they are cross-polarized. I wrote an article on Micscape about my setup that you can find here http://www.microscopy-uk.org.uk/mag/ind ... polar.htmlI am using two circular polarizers. The top one is the analyzer. The one on the light source is the polarizer. It does matter that the polarizers agree. In other words, if the light is going through the analyzer at the non-thread side, then the polarizer should also be aligned with th thread side up. But, at times, I may flip the polarizer to see what effect that will have.
Then I have a polarizer on the left eyepiece to examine the specimen slide. I usually have to rotate the polarizer when I view and shoot in the camera. I am now using an Olympus E-330 which has Live View from the sensor and an articulated screen. Olympus Live View has a 7x magnified view so I can fine focus. I also stop the condenser diaphragm almost all of the way down for deeper depth of field and to accomodate field flatness.

Mike

rcroning · Post by **rcroning** » Sat Feb 14, 2015 2:20 pm

Thanks for the info. I have bookmarked the link you sent me. Will read through it soon. I may have some questions if you don't mind.

I have recently been photographing meteorite thin sections in cross-polarized light and I use two 58mm linear polarizers. Works great.

Do you find any difference between linear and circular polarizers?

Olympusman · Post by **Olympusman** » Sun Feb 15, 2015 9:48 am

Circular polarizers have a quarter wave filter in them to prevent the polarization from affecting the performance of autofocus and exposure systems in modern cameras. I suspect this may result in a more profound polarization effect from what I have read about filters used in actual petrographic microscopes. Maybe someone has more information.
What I do know from my tests is that if you are going to cross-polarize it should be a match of two circulars or two linears, not a circular and a linear.

Mike

Pau · Post by **Pau** » Sun Feb 15, 2015 10:20 am

In another of your posts I answered this question, perhaps you didn't read it

http://www.photomacrography.net/forum/v ... 757#163757

All what you need is two actual polarizers facing one each other, no problem to combine one linear with one circular used that way

Citric Acid

Citric Acid

Cross-polarization

Polarizers