100x oil vs 40x water

[neal Shields]

I got my DiatomLab #2 test slide in and ran some tests. (I love the test slide)

https://www.flickr.com/photos/196001110 ... ed-public/

Olympus UplanFl Ph Oil 100x vs Olympus UAPO340 water 40x

I used the #5 diatom on the slide (hardest to resolve).

In my opinion I can resolve about as much detail with the 40x APO objective as I can with the 100x oil fluorite.

100x oil:
Phase
https://www.flickr.com/photos/196001110 ... ed-public/
DIC
https://www.flickr.com/photos/196001110 ... ed-public/

40x water:
DIC (it doesn't have a phase ring)
https://www.flickr.com/photos/196001110 ... ed-public/
https://www.flickr.com/photos/196001110 ... ed-public/

All photos were taken with the blue filter in place.

To my mind this validates my rationalization for purchasing the water immersion lens. I can use it with a 20X eyepiece and get similar results as a 100x with 10x eyepiece, without the messy oil.

Note: the 40x lens has the wrong back focal distance -25 for my condenser Nomarski prism which is optimized for -19. I am not seeing a significant impairment. I tried using a 5mm spacer and it made no desirable difference.

Maybe I just don't know how to optimize my 100x lens but I was VERY careful with setup and alignment. (I didn't however pay a lot of attention to the NA of the immersion oil)

Comments appreciated.

Neal

[apochronaut]

What do you mean by NA of the immersion oil? Immersion oil doesn't really have an N.A. It's suitability for it's application in microscopy is measured on the basis of refractive index.

[Scarodactyl]

The 40x results look nice but the 100x looks like it is likely not performing as it should.

[neal Shields]

"The 40x results look nice but the 100x looks like it is likely not performing as it should."

I tend to agree. I need to learn more about how to judge what I should be seeing on the test slide at 100x.

The 100x lens has an NA of 1.3 but I have a dry condenser with an NA of .9 so according to a formula I found on the Olympus web site the total resolution is 285 instead of 250. With the same condenser the water objective has an NA of 1.15 for a resolution with a .9 condenser of 306.

I would think I could see more of a positive difference with the 100x oil.

Yes, I meant refractive index not NA of the oil and that could still be the problem.

Most of the objective manufacturers say it will make a noticeable difference.

The oil I used was Carolina "D =1.5150

I have tried to do some measurements and the distance between the dots measures .001 mm which should be close to optimal proformance?

Neal

[neal Shields]

I went back and think i did better.

This is 100x oil FL PH NA 1.3 with a .9 dry condenser. I have a 1.2 oil condenser, but not phase and I got better results with the phase.

https://www.flickr.com/photos/196001110 ... ed-public/

I think I am now seeing the Poroids but my test slide seems to have different diatoms than the Diatomlab instructions so I a not sure if I am actually resolving the detail they describe.

I would love to see the results that others get from the Diatomlab test slide #2

Neal