40X Oil Infinity Objective

[p3aul]

I recently received a pair of 16X EP's and I love them! I turned up the light and my blood cells look sharp and crisp and a kind of translucent gold color( I have no Wright's Stain). For my next purchase I would like to get a 40X Oil objective but the only one I can find is for infinity microscopes. My feeling is that 160 mm is contained in the set {Infinity} so they should work, right? or Wrong

Thanks,
Paul

[zzffnn]

In general, 160mm or any finite tube length optics are not compatible with infinity optics.

May I suggest reading online resources or library books to obtain basic microscopy knowledge:

http://www.olympus-ims.com/en/microscop ... feature15/

http://www.microscopy-uk.org.uk/mag/ind ... inity.html

[JimT]

Zzffnn is right. And, you don't need oil for a 40X obj.

JimT

[p3aul]

zzffnn: I don't need basic microscopy knowledge. If you are going to put me down with every comment you post. Please don't post at all. I can do without the negativity.

JimT I know you mean well, but if I didn't need oil type 40X. why do they make them? For more resolution and clarity of course.
Thanks,
Paul

[JimT]

P3aul, good luck on your own.

We all mean well but you know how to discourage folks from offering advice and suggestions.

Adios

[p3aul]

Well that's up to you Jim, but I was not referring to you; only to zzffnn. Every post of his is either a put down on my choice of scopes or a put down on my experience. I didn't mean to be rude but I have had enough of his rudeness, unsuccessfully described as helpfulness.

I guess I shall get kicked out by the moderators, but no else in this group has been like this. The rest of you have been supportive and helpful.

I was merely saying that on the logic of it you must be mistaken. This is just a matter of opinion and I didn't mean anything else.

Paul

[apochronaut]

medium power oil objectives( 40-50X) are not normally used for a number of very practical reasons, so JIm T is correct when it comes to what might be called average or maybe more correctly standard microscopy but when they are used, it is also for a number of very practical reasons.
one of the great delights of using them is that once you take the plunge and go to high power oil objectives, you often can lose your subject or realize that you need a broader look. going back to an oil 40 or 50 , makes this so easy and effortless and then you can also go back to the high power oil with ease. there are several other bonuses. most of them work at very high N.A.s , so their imaging is stellar but when used dry , they are often so close to the N.A. of a standard dry 40X that , you won't miss having the 40X .65 high dry objective around . when used with oil their resolution is so good, that you can use 15X eyepieces with them with no empty magnification, so you can get a nice intermediate magnification. most of them are fluorite or apo too. really, I can't speak highly enough of them. i do have one or two very high N.A. dry 40's that i am really partial to and use regularly but if i know that i am going to be using a 100X oil objective , i almost always put a 40X oil ahead of it.

this may sound like a lot of fluff due to the choices involved but if i had only one choice, and a 160mm microscope, i would get a B&L 40X oil fluorite. they made great ones; 40X 1.00 N.A. oil( 160mm) short bodied. . used as a dry objective they are very good. for infinity , Reichert ( Austria) had a 40X 1.00 oil planapo (D.I.N.) works well on an AO/Reichert Microstar IV or Diastar 420. i'm sure there are lots of others. 50X too.

[zzffnn]

I am sorry, Paul. You took me wrong.

We can answer your questions one by one, like this:
1) no, you should not mix 160TL with infinity optics;
2) no, you should not immerse dry objectives into water;
3) no, you should not use oil immersion objectives dry, in general.

But you would learn a lot more by reading, say, an online article about immersion microscopy. That would answer your questions 2) and 3) and any related future questions in one sitting.

It also makes it easier for others to comment specifically, when you have understood the basics. A lot of the times, online articles and books are written by experts in the field, and they explain things better than amateurs in online forums.

By reading yourself, you also gain a deeper understanding and can even use that knowledge to DIY and save money.

There are also special exceptions to general rules. What I said in points 1)-3) has exceptions. But it would take a whole article to list and explain those. Very few people would be willing to explain those in details. You want to read them yourself.

Also there is the personal preference and different application scenarios, when other microscopists provide comments. Without a deeper understanding, you may be easily confused by different advices.

Edit:

For example, 40x oil objectives exist and have their applications, but they are not very popular (many people prefer dry ones). Sometimes high NA can have shallow focus depth and halos. And oil can get very messy and sticky. Maybe you can buy one and try it out to judge yourself. This is where personal preference comes in.

I can tell you that the benefit of 40x oil objective is that it produces minimal spherical aberration and is not affected by tube length or cover thickness variations (not as much as dry objective of same NA). Do those terms make sense to you? If your following questions are: what are those? Why? And so what? Then we are back to basics again. I don't really want to explain, again, what experts have already explained before in online articles.

[JimT]

P3aul, I was coming back to retract my previous post but others got here before me. None of us intend to "Talk down" to anyone.

Stick around. I take back my "Adios"

JimT

[p3aul]

Thanks, all of you! Since I can't use infinity objectives, I'll try your suggestion of a B&L, zzffnn, if I can find one and they aren't too expensive.

The suggestion of books and websites are good, but you can't ask questions or clarifications of a book! Whether you realize it or not I always search the forum, both new and old for answers also. I don't know when I last opened a "paper" book since I discovered digital "books"!

You guys are a great source of information on any microscopic topic and I would certainly miss out if I couldn't query any of you!
Thanks,
Paul

[apochronaut]

Paul. I will post some pictures for you. It might help you make a decision . I have enough of those objectives , that I can show you their performance, not just theorize about it.

[p3aul]

[UPDATE] Do you use oil on the condenser also to have a complete path for the light?
Great Apoch, Thanks I always love to look at images others have made. I have a question about image quality and will show some of my own images but I better post in the right forum, it's off topic here. I just checked Ebay and there is an excellent(to me) B&L 40X Oil for $90 if I [Buy it Now] which i would do for I have no luck bidding! Check it out for me, will you?
Here is the URL: http://www.ebay.com/itm/Bausch-Lomb-40X ... 8A6BsWiKbg

[apochronaut]

The only issue on that Paul, is that you are planning on putting it on your Amscope, which has D.I.N. optics, I think. The B & L is short, so will not be parfocal. It will work but the difference in the objective length will be really annoying. You will be crashing into slides for sure, even if you take care because those things happen. Let me check one out for you with an extension, to make it parfocal to D.I.N. and see how it performs. I won't be able to do it until Sunday or Monday.

[zzffnn]

apo,

According to theory, NA 1.0 oil immersion can tolerate around 12-15 mm tube variation: https://www.google.com/search?site=webh ... OCzrb9M%3A

So chances are good. I may go that direction too, in the future. Please keep one of your 40x oil for me. AO is preferred, but B&L will work too. What is the PFD of B&L, around 36mm?

[apochronaut]

Yes but a lot of those theories are based on various other factors being static. Spherical aberration is affected by the distance between the rear of the front lens and the face of the second lens pack. Two objectives with the same N.A. could easily respond differently to such a lengthening of the tube. I always use the rule of, thumbs on the device to be tested and test it.

[p3aul]

Wow! Microscopes are a lot more complicated then telescopes!
Apoch, I'm not going to purchase immediately, but I am glad you've cleared that up for me. I have sent a question to the seller. asking if it was DIN. If it's shorter and will cause problems, I can do without it for now.

Thanks,
Paul

[apochronaut]

It's not D.I.N., it's around 35mm in length, D.I.N. are 45mm. I'll post some comparison pictures anyway. I'm sure it would be of interest to a few others.

[zzffnn]

Yes, please do, apo. I am interested.

[JimT]

Wow! Microscopes are a lot more complicated then telescopes!

P3aul, don't know how old you are but back in the '50 it was a big deal to grind your own mirror. I never even thought about trying it. Talk about complicated Now-a-days the hardest thing is finding dark skies.

JimT

[p3aul]

I never tried it but my brother did. It was a six inch and he gave up on it about halfway through, It wasn't so much complicated as it was tedious. It was hours and hours of grinding! I was born in 1942 and just now achieving my childhood dreams of both a telescope and a microscope! I kinda think I made a mistake about the telescope I got for Christmas. It's a Dobson mount and takes both me and my wife to carry it outside!

Oh, and now I got this 60 lb monster and it's too cold to bring it out!

[apochronaut]

Here are the tests I did with a series of objectives, all made by the same mfg. in the 1950's. They are all Bausch & Lomb and were made just as coating technology was just coming in, which at the time was an option you could order for a premium. For the test I used the chromosomes of a rapidly dividing fish blastula, unstained. Objectives tested were 43x .65, 43x .65 coated, 45x .85 strain free, 40x 1.0 oil immersion without oil, 45x .95 apochromat with a correction collar adjusted for the .15 coverslip and the last is again the 40x 1.0 oil immersion , immersed.

The test is to show the comparison of a 40x oil objective to other dry objectives and as well as a dry objective.
This subject demands quite a defined subject. With some stained subjects, there was no discernible difference between the 43x .65 and the 40X oil immersion objective used dry. This particular subject was chosen because it illustrates the differences more than other subjects I tried out.

[apochronaut]

one more.

[75RR]

Disappointed with the 40X 1.0 oil immersion ,oiled. It should have stood out a mile.

[zzffnn]

Thank you, Phil.

The worst seems to be the 40x oil used dry. Coated NA 0.65 40x is surprisingly good. 40x oil used oiled did not stand out at all. Nor did dry NA 0.95 or dry 0.85 40x.

Was your camera set to auto focus or full manual operation? If auto, then this set of photos are not comparable, as camera may have changed exposure slightly between photos. I know you most likely used it at all manual, just want to confirm.

The resolution target is hard on my eyes, very busy and unfamiliar....... But I understand why you picked it.

[apochronaut]

Probably, 75RR, if I took the apochromat out of the test, as far as detail goes, the 40X oil would be the best, with respect to detail. It's impossible for all other objective types to equal apochromat performance, irregardless of when they were made, whether oil or not.
The confounding thing , is the coated 43X .65 objective and the extreme level of contrast difference, it provides. It makes the objective look sharper, when in fact it isn't. That , to some degree makes the 40X oil seem poorer when in fact , if the detail is examined of the chromosomes, it clearly has superior resolution to the achromats.
I made no effort to adjust for factors such as contrast and all were tested with a dry condenser, so that might have downgraded the N.A. 1.0 objective slightly, too.
The real point of the test was to show that: if you know your ultimate goal is to be using high power oil immersion, then a 40 X 1.0 like this, is an adequate dry objective , with which to get there and then , also a good medium power oil objective to back down to with ease, if necessary.

[75RR]

... all were tested with a dry condenser ...

That could have been it, I oiled my condenser prior to using an oil objective and the view through the dry 40x was much improved.

[apochronaut]

Thank you, Phil.

The worst seems to be the 40x oil used dry. Coated NA 0.65 40x is surprisingly good. 40x oil used oiled did not stand out at all. Nor did dry NA 0.95 or dry 0.85 40x.

Was your camera set to auto focus or full manual operation? If auto, then this set of photos are not comparable, as camera may have changed exposure slightly between photos. I know you most likely used it at all manual, just want to confirm.

The resolution target is hard on my eyes, very busy and unfamiliar....... But I understand why you picked it.

I think, Fan if you zero in on the chromosomes, you will see the resolution differences.

[zzffnn]

Looking at the details (lines/dots) of the chromosomes, the NA 0.95 apo is indeed visibly better. Edit: I would give runner-up to the 40x oil, in that respect, but 3rd is very hard to pick as all the rest are quite behind, maybe the coated would get my 3rd pick.

I was looking at peripheries and overall image intensity, which may have favored the coated NA 0.65 and given the oil dry disadvantage.

That is why such a busy target is hard on eyes. Judgements can change when you look at different things. I should have looked at central resolution though, my bad.

[apochronaut]

When I first looked at them, the contrast level of the coated 43X .65 achromat , had me wooed as well. It seems to give a more complete picture somehow. Perhaps it's because , with lower contrast it is a bit of a strain on the eyes to discern the details, even though they are there.

I also was disappointed in the performance of the 45X .85 achromat, when compared to the coated 43X .65, initially seeing it as being inferior. However, after a more complete perusal of the images, I saw things a bit differently.

Sometimes, with average optics that have otherwise good contrast, fine grey lines and points which are obscured due to diffraction blur, can look very contrasty; as thicker black bars and heavy dots, when in fact with lower contrast they are seen more as what they are. This gives rise to what I call false contrast. The apochromat in this set of pictures is , as you say Fan, visibly better, in both detail and contrast, with superior flatness of field and resolution towards the edges, as well as the center. The fluorite oil would be my second pick but it is possibly suffering more from an N.A. reduction due to the lack of oil on the condenser leaving it's original "airless" specification in mid air, so to speak. Although, the 45X .85 objective seems a bit flat, with less depth of field, than the others, I would still place it third. One look at the chromosome resolution with it , compared to the last 3 and it's an easy call. The resolution of the chromosomes with the coated 43X .65 is not very good, with the high contrast dissolving into a lot of blur. I think , even the uncoated 43X .65 might be better.

These are all non plan objectives, with the typical level of field curvature that was common in the day. The apochromat, does have a much flatter field, which is a typical feature of apochromats. They were the original plan objectives, with superior corrections all around, even though, when they were first being made, the concept of plan did not really exist.
I should also point out that this is a very difficult specimen to resolve and has more of a gray scale of contrast than contrast.

[zzffnn]

Phil,

I admire your skills and patience in daring to use such a specimen for those many comparisons. Just comparing those photos to pick 1st-2nd-3rd gave me a big headache. I think without looking at eyepieces, my personal bias and preference comes into play for the 3rd placement. But we agree on 1st and 2nd placement, after fixing the view point, that served as a reference for me. Next time, I will just take your first pick happily, headache-causing photos are not needed