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Can I expect a better picture (photograph) resolution from a Nikon Plan APO 40x objective screwed into an OMAX (Chinese Microscope) than the objectives that came with the OMAX microscope?

Are they designed for the same tube length? If yes your best chances are using a matched Nikon eyepiece.

There are some provisos with the adoption of objectives higher up on the food chain.

The first is tube length,, which has been dealt with.

#2 is parfocality. Your OMAX is 45mm. Nikon made both short barrel( 34mm?) and long barrel 45mm objectives corrected for a 160mm tube . The short tube objectives will work but might be a bit cumbersome to use.

#3 is working distance. A 40X planapo will likely be a .95 N.A. with a correction collar. They usually are rather picky about coverslip thickness irregardless of whether they have a correction collar or not, because often the sample thickness doesn't get included in the calculation of the cover thickness. There have been cases, where a .95 N.A. objective is impossible to focus, even with the correct coverslip thickness and a properly adjusted collar because the sample is too thick. This sort of thing doesn't happen with a .65 objective. Objectives of .70 to .85 are only marginally less good( some can be even better) and much easier to manage. These will have no correction collar, usually but they do need precise control of the sample thickness.

#4 is the eyepiece compatability, which has also been dealt with. The older the objective is, the more likely it is that it needs compensating eyepieces. At any rate, it is always advisable to use eyepieces that are matched to the objective and that info. should be available from the relavent Nikon literature. This poses another different problem, than the issue of parfocality, in terms of the compatability with your existing objectives. The OMAX are going to need diferent eyepieces than the Nikon objective, irregardless of all else.

If you like the stand, it might be time to consider renovating all of the optics to a somewhat improved matched set. You wouldn't have to blow a bundle on all planapos. Planfluorites or even some of the better Nikon Planachros would probably help a lot. Planfluorites are often overlooked in favour of planapos. They are a more forgiving objective and good ones can do most of the work of a planapo, and at much lower cost usually.

I have both a 40X .70 planfluorite and a 40X 1.0 oil immersion planapo, both parfocal for the same microscope. I only use the planapo for DF. The planflourite does not offer quite as highly resolved an image but with fresh water samples it is so forgiving of sample thickness tolerances that the small difference is easily overlooked. It is far superior to a planachromat and in fact has a slightly longer working distance than a 25X .65 planapo it is usually teamed with.

There are lots of 45mm parfocal possibilities aside from Nikon out there( Olympus,Zeiss,Leitz,Vickers, even Chinese) but if you are renovating the entire optical system you may be able to shy away from 45mm and get some bargains in higher end objectives with non-D.I.N. parfocality; if your microscope has the extra 10mm focus.

Apochronaut, your detailed response is appreciated!!

On your #3 is working distance. Comment.

Would an oil objective with a 1.0 N.A. be better than a dry objective with a 0.95 N.A?
I have two choices both are used and at the same price.
1) Nikon Plan APO 40x /0.95 DRY 160 TL with Collar RMS
2) Nikon Plan APO 40x /1.0 OIL 160 TL RMS

I am projecting images through a camera so I am assuming eyepieces will not be a large concern? Have a few camera barrel adapters with 0.3x, 0.5x and 0.7x reduction lenses. Not sure if these have the same function as eyepieces and reduction lenses have to be matched.

That is kind of a personal choice. One of the principal reasons for mid-magnification oil objectives to exist is that they are more user friendly with oil immersion high magnification objectives. Having to use oil is a little annoying but if you are in a session with a 60 or 100x oil immersion objective anyway, it is less annoying than a dry collared objective , if you need to get a wider view of your sample , once the slide has been oiled .

If you don't normally use high magnification with oil, then probably the dry objective would suffice. I don't know for sure , how much better the 40X 1.0 oil is than the 40X .95 but the performance of the .95 is partially dependent on achieving a precise set up, whereas with oil immersion the set up is achieved via the oil interface.
Remember too that there are Nikon planapo and Nikon CF planapo, so there are differences between those too. I believe those need differing compatible eyepieces CFW and CFWN respectably. Someone more familiar with Nikon than I , would know more about their compatability specs and performance characteristics.

lperepol wrote: ↑

Thu Oct 17, 2019 8:49 pm

Can I expect a better picture (photograph) resolution from a Nikon Plan APO 40x objective screwed into an OMAX (Chinese Microscope) than the objectives that came with the OMAX microscope?

I looked up your system: https://www.amazon.com/OMAX-40X-2500X-C ... 470&sr=8-3

You do not say if that objective is Ph - be a shame to lose Phase if it is not (assuming the phase ring is compatible)

I would suggest that if you are thinking of upgrading your objectives to Nikon, whether Plan or Plan Apo you do so with a Nikon Stand.

This will give you access to a modular microscope system that will allow compatibility between a variety of objectives, eyepieces, condensers and any illumination technique within the system that you may wish to include now or in the future.

Nothing wrong with outgrowing your microscope - in fact you could take it as a good sign. It is what starter microscopes are for. Sell up and move up.

If you are considering upgrading have a good look around first. Best way to get a good set of objectives is to buy a complete stand.

Anyone of the big four will do you well, it is more a question of what is on offer than any particular brand.

Hi 75RR,

I am saving up to upgrade to a DIC microscope. In the meantime, I was considering better objectives for the OMAX. And pass it on to my nephew. He is interested in biological sciences. Keeping expenses low. Not sure it would be worthwhile. I may be able to re-purpose higher-end objectives on a better scope.

I am struggling with variability in photographic quality of pictures, some come out well others are quite bad. There are many variables -- operator error is most likely the largest contributor -- fixing, mounting, focusing. I seem to see more aberration (fuzziness) using phase-contrast compared to just brightfield.

I have a Nikon 40x Phase contrast objective. The ring matches well with what came with the OMAX.

I'll post some pictures comparing images from the objectives I have so far. It will help me take a closer look at what is going on. I am studying nematodes in my geographic area and counting how many species may be in the area. Still struggling with cleaning nematodes. I have not mastered picking them up with an eyelash glued to the end of a chopstick to observe a clean specimen.

I am enjoying this.

apochronaut wrote: ↑

Fri Oct 18, 2019 11:36 am

Remember too that there are Nikon planapo and Nikon CF planapo, so there are differences between those too. I believe those need differing compatible eyepieces CFW and CFWN respectably. Someone more familiar with Nikon than I , would know more about their compatability specs and performance characteristics.

CFW and CFWN eyepieces are interchangeable.

The CFW 10x/18 eyepieces were produced with the first generation Nikon CF ("chrome-free") objectives. These objectives have plain metal barrels.

The CFWN 10x/20 eyepieces were introduced a little later when many (but not all) chrome-free objectives where improved and updated. This second generation is known as CFN ("CF new"; in Japanese literature they are called NCF). CFN objectives are easy to identify by the knurled metal ring on the barrel.

CFN objectives have a little higher NA than their CF counterparts (e.g. my CF PlanApo 60x has a NA of 0.90, whereas the CFN PlanApo version has a NA of 0.95). But they are both "chrome-free" so they are design to be used with non-compensating eyepieces. In the catalogue on Charles Krebs homepage, both CF and CFN designs are listed side by side, as not all objective designs were updated.

The earlier, pre-CF, short-barrel Nikon objectives made for the black S-series microscopes, however, do need matching compensating eyepieces.

Similar discussion:
viewtopic.php?t=3482

lperepol wrote: ↑

Mon Nov 04, 2019 1:47 pm

Similar discussion:
viewtopic.php?t=3482

A very educational discussion ^^ .