Question about Olympus 40x Splan Apo

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mintakax
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Question about Olympus 40x Splan Apo

#1 Post by mintakax » Thu Sep 19, 2019 4:08 am

On my BHS/BH2, I've been using 10x and 20x Splan Apos and a 40x Splan Acro with DIC. I wanted an improvement for the 40x and I found an Splan 40x APO with correction sleeve for a decent price and It just arrived today. 95% of my microscope use involves using well slides and that will always be the case, however it seems that the new 40x objective will just not focus through the well without hitting the cover slide(No 1.5H), regardless of the correction setting. I should have known given the short WD. Flat slides are not an issue. I really liked the improvement that the APO made, especially with color fringing at edges. Might there be a 40x from another manufacturer that would work with the Olympus DIC optics and be an improvement over the Splan Acro ?

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Re: Question about Olympus 40x Splan Apo

#2 Post by MikeBradley » Thu Sep 19, 2019 6:43 am

Olympus make a range of LWD and ULWD objectives for use with inverted brightfield microscopes. The 40x have working distances of 2 and 7 mm respectively and work with DIC. Pricey though!
See page 12 in this manual on Alan Woods' site.
http://www.alanwood.net/downloads/olymp ... ctives.pdf

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apochronaut
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Re: Question about Olympus 40x Splan Apo

#3 Post by apochronaut » Thu Sep 19, 2019 11:44 am

This seems to be a coverslip issue. Coverslip thickness recommendations do not exist outside of considerations for sample thickness, so when you increase the sample thickness, the w.d. is increased as well . Although you are using .17 coverslips, they act more like .22 or even greater in such a situation. Objectives with an N.A. below what you have been previously using can tolerate the increased w.d. requirements , at least in order to focus, although I would suspect that with a deep aqueous sample the imaging on a standard 40X .65 objective would suffer somewhat. Bumping up to a .95 , even with a correction collar, puts severe limitations on the w.d. of the objective , that's why mfg. offer objectives with extreme w.d.'s. In lieu of blowing a lot of money on a high w.d. planapo, I would try very thin coverslips. Buy a box of regular 0 coverslips and a micrometer and try out various thicknesses. That's less expensive than a box of 1.5H. They will be up to about .13, so probably within bounds for you to get deep focus.

I realize that the iso standard is a 1.5H for super resolution microscopey but I don't think that was arrived at using a well slide.

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75RR
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Re: Question about Olympus 40x Splan Apo

#4 Post by 75RR » Thu Sep 19, 2019 1:10 pm

Olympus make a range of LWD and ULWD objectives for use with inverted brightfield microscopes. The 40x have working distances of 2 and 7 mm respectively and work with DIC. Pricey though!
See page 12 in this manual on Alan Woods' site.
If you are going to insist on exclusively using well slides then this is the best option.


The objective you bought, and indeed any regular high magnification/high NA objective is effectively ruled out when using well slides due to the minuscule working distance.

Note that with regular high magnification/high NA objectives, the working distance given requires that the subject be touching the underside of the cover slip.

Any space between the subject and the cover slip degrades the image. The more space, the more it is degraded.
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Re: Question about Olympus 40x Splan Apo

#5 Post by mintakax » Thu Sep 19, 2019 2:05 pm

75RR wrote:
Thu Sep 19, 2019 1:10 pm
Olympus make a range of LWD and ULWD objectives for use with inverted brightfield microscopes. The 40x have working distances of 2 and 7 mm respectively and work with DIC. Pricey though!
See page 12 in this manual on Alan Woods' site.
If you are going to insist on exclusively using well slides then this is the best option.

The objective you bought, and indeed any high magnification/high NA objective is effectively out of bounds when using well slides.
Thank you Micheal, apochronaut and 75RR. I'm just starting learning about how objectives work. I think I'm beginning to understand why a well slide might not be appropriate for a 40x high NA , low w.d. objective. Still, I am going to try apochronaut's suggestion of 0 thickness cover-slips. On a flat slide, the difference between the 40x Apo and the 40x Acro was pretty noticeable to me.

Probably more appropriate for a different thread, but the thought keeps coming to me that I might be better off with an inverted microscope ? My main interest is recording videos at the highest resolution possible.

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75RR
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Re: Question about Olympus 40x Splan Apo

#6 Post by 75RR » Thu Sep 19, 2019 4:35 pm

mintakax wrote:
Thu Sep 19, 2019 2:05 pm
Probably more appropriate for a different thread, but the thought keeps coming to me that I might be better off with an inverted microscope ?
My main interest is recording videos at the highest resolution possible.
An inverted microscope does seem at first glance to be a viable alternative, no cover glass to flatten the animalcula for example.

It does however limit you to relatively low NA objectives.
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Re: Question about Olympus 40x Splan Apo

#7 Post by mintakax » Thu Sep 19, 2019 6:19 pm

Thank you 75RR-- I think I'm just going to be happy with what I have :). Use the 40x Apo when I have the opportunity for flat slides, other wise use the 40x Acro.

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