Using a metallurgical microscope to view biological subjects

benjamind2014 · Post by **benjamind2014** » Mon Mar 23, 2015 6:15 pm

Is this possible? I always thought that it could be done.

The microscope I am thinking of getting is one from an Australian supplier rather than from O/S.

https://proscitech.com/?navaction=show_ ... =o&page=10

The one I am interested in is the OXJM904 with both reflected and transmitted light.

I think it would be a good option. It seems to appeal to my interest in studying tiny objects with good detail.

With the transmitted light part is this possible?

Is it also possible to get images like this below using the polarization features?

http://www.microscopy-uk.org.uk/mag/img ... 228768.jpg

Pau · Post by **Pau** » Tue Mar 24, 2015 12:26 am

Yes, the microscope you link seems to have both transmitted and incident light, be sure of that, the image shows an opaque stage!, so it would be adequate, just be aware of:

- metallurgical objectives are designed to work without cover glass. This doesn't matter for the 4X and 10X (NA up to 0.3) but for higher magnification /NA you'll need to buy objectives corrected for 0.17 cover for standard biological specimens glass covered.

- For transmitted pol like your sample image the 4X objective not included is most useful (and for epi too)

- No idea about the quality, the objectives seem the same as Cnscope tested somewhere at the forum. It seems a good chinese generic instrument.

benjamind2014 · Post by **benjamind2014** » Tue Mar 24, 2015 1:57 pm

Thanks for that advice. It is still very interesting and I think I am going to go for this option. I know there are always compromises no matter what I choose so this one looks most suitable.

To get the above picture what would I need to do with the polarizer? Is this done with cross polarization? Do I need a rotatable polarizer and a rotatable analyzer?

Pau · Post by **Pau** » Tue Mar 24, 2015 2:53 pm

benjamind2014 wrote: To get the above picture what would I need to do with the polarizer? Is this done with cross polarization? Do I need a rotatable polarizer and a rotatable analyzer?

It seems that with the 904 model you get both filters. The picture you show is taken with crossed polarizers. usually you only need one of the filters to be rotatable to get crossed or parallel position. Although not strictly necessary but nice to have and typical part not present and very useful in pol microscopes is a rotatable circular stage.

Admin note: if the sample image is not yours, please delete it and post in its place the link to the original site

parcival · Post by **parcival** » Wed Apr 01, 2015 1:09 pm

The little experience i have with metallurgical objectives is that besides not performing well through a cover slip, that the depth of focus is very limited, with the 50x i have it is not possible to get the whole of an (uncovered) pollen grain into focus. They are normally used to look at a polished surface that is very flat.

Chris S. · Post by **Chris S.** » Wed Apr 01, 2015 9:38 pm

parcival wrote:The little experience i have with metallurgical objectives is that . . . the depth of focus is very limited, with the 50x i have it is not possible to get the whole of an (uncovered) pollen grain into focus. They are normally used to look at a polished surface that is very flat.

For clarity, let me point out that depth of field is independent of whether an objective was designed for metallurgical or biological use, but is a factor of the lens' numerical aperture. Any decent 50x objective will have a high enough NA--and correspondingly low depth of field--to get only a small portion of most pollen grains into focus. But of course, we can easily focus-stack pollen grains.

--Chris