New to this Forum

[finiteguy]

Hi All, I'm new to this forum. I have several microscopes one of which is an old Unitron. There was a missing objective lens, and I found a unitron phase contrast obective on ebay and bought it. My question is, what is different about this objective lens? It does work fine, but what would be the difference between the phase contrast objective and a standard one.

[dtsh]

The phase contrast objective has a annulus, an opaque ring, blocking some of the aperture of the lens. It is there to match up with another similar ring that would be in the phase contrast condenser so that when the light passes through, you get the effect of the light waves interacting to increase contrast. I.e. it allows using the slight changes in the light wave as it passes through a specimen to create a visible change in the contrast. It has some disadvantages, but for your purposes the primary disadvantage will be reduced contrast. It will work, but it won't ever produce great results.

I am new to phase contrast myself, but that is a simple explanation as I understand it.