Desmids

[Olympusman]

I just got a new 60x dry objective and am getting the hang of it. Even with a 0.17 cover slip there is so little working distance that I have to draw excess water from under the cover slip by holding a piece of toilet paper against the edge of the slide to keep the cover slip from floating.
Here are a few desmid stack tests:

Cosmarium biretum

[Olympusman]

Sorry -- here are the others:

Cosmarium perforatum



Staurastrum armigerum



Micrasterias truncata

[vasselle]

Très belles séries de photo
J'aime beaucoup la sernière

[jswatts]

These are great shots, Michael, especially that last Micrasterias. I've generally found when working with this sort of sample that large 22mm x 50mm coverslips are really helpful. Also, there's a bit of an art to letting just enough of the water to evaporate to suit the particular thing you're shooting: not enough and the little darlin's have too much freedom; too long and they're squished.

[75RR]

I just got a new 60x dry objective

Congratulations!
Agree with jswatts, last one very nice.
Had not foreseen the working distance limitations, good to know.

[Olympusman]

Thanks guys.
When I bought my microtome, the retired doctor who sold it to me me threw in a couple of thousand slides and several thousand 25x40 and 25x50mm cover slips all of which are .22 mm. ( I test them with a digital caliper). This new objective requires .17 mm cover slips, but the working distance is so close that when I go from the 40x objective to the 60x, before I rotate the turret I have to drop the stage for clearance and then walk the focus into the subject. If I try to use the .22 slips, the objective strikes the slip before I can achieve focus. That said, for $60 on ebay, I can't complain and am please with the image quality.
I have an Olympus 60x that has very generous working distance but because of the lens flare, it is useless unless I stop the condenser all the way down and the image quality gets very poor -- primarily chromatic abberation.