MicrobeHunter.com Microscopy Forum

If ever you have a RMS 2.5x plan objective to sell
But not a very expensive Mitotuyo !

please PM me

You would have to be more specific regarding what use you want to put it to and what you need to use it in. There are a number of different types of plan 2.5X objectives with each one useable in only certain optical systems.
The Mitutoyo you referenced is not RMS and almost all Mitutoyo objectives are made for jndustrial and metallurgical applications, without a cover slip.

or are you looking for a photo macro lens?

Yeah, some more details would help. I dkn't have one any more, but I had an olympus 2.5x apo which was quite good. That's rms but also infinity corrected.
Mitutoyos are actually sometimes going to be on the cheap end for this magnification. Their 2x is not nearly as well corrected as others in the line and the price often reflects that. I would only ever recommend it as a convenience since it's parfocal with their better objectives.

A Leitz PL 2.5/0.08 could be found for less than 100 USD.

Of course Zeiss has several too, but the finite versions require the compensating eyepiece I think. What is the setup?

Thank you all for your answers and comment.

I am looking for a 160 objective and that's to use for photo on a microscope of which head has been replaced by tubes and an M4/3 body

Generally I use this setup to make insects genitalia pictures on a slide and also cover slide in glycerin mount

As for some larger genitalia, the field with a 4x objective is already to small, I want to try with a lower magnification.....

Milou wrote: ↑

Thu Jan 20, 2022 9:48 am

As for some larger genitalia, the field with a 4x objective is already to small …

Wow !!

MichaelG.

You didn't by any chance used to play bass in the band Primus did you? Les Claypool?

https://youtu.be/aYDfwUJzYQg

apochronaut wrote: ↑

Thu Jan 20, 2022 3:56 pm

You didn't by any chance used to play bass in the band Primus did you? Les Claypool?

https://youtu.be/aYDfwUJzYQg

?

Just a joke. There are some inexpensive Lomo 2.5X planachromats on ebay. Have you seen those?
Such as https://www.ebay.ca/itm/185205239150?ep ... SwUi9hsPY3 There may be others a little cheaper.

Thank you for information about these Lomo objectives.
But I have no idea about characteristics and quality of these pol. ones!

Pol objectives are standard BF objectives that are built to a higher degree of precision than normal. Care is taken to eliminate any alignment stress on the glass or doublet cement during assembly as well as internal and external reflections due to the design.

There is no reason a pol objective would not perform well in BF.

It is not usually ideal to mix objectives from different manufacturers in a direct projection photo settup, especially very low power ones. It sounds like you have no internediary optics between the objective and the camera? If you are achieving good correction and planarity at the corners of your camera frame now, it would be a good idea to look for a 2.5X plan objective from the same series of objectives you are already using, although very low power objectives in older objective series sometimes are not as well corrected as those of 4X and up. They are plan but over a narrower field. Lomo plan objectives seem to be plan over about an 18mm f.o.v. and work well with Lomo eyepieces as well as Olympus Bi 10X W.F. eyepieces. What objectives are you currently using?

Thank's for information about pol. Lomo objectives.

Presently I've chinese cheap plan objectives (4x and 10x) like this: https://www.ebay.fr/itm/324135181148?var=513190400575
As I use them almost exclusively for pictures with my M4/3 on tubes (replacing Leitz SM-Lux head), I think it is perhaps not usually ideal to mix this Lomo with chines ones (they are surely not parfocal!)!
But there are not a lot of cheap plan low magnification objectives at least not in these chinese serie

The plan about 18mm fov you note for this Lomo objective, seems to be small for me !
Perhaps this kind of objective would have a larger one?
CARL ZEISS JENA Polarisant Objectif PLAN 2,5x 0,07 160/- Pol (in ebay offers)

I have no internediary optics between the objective and the camera

I also have the original Leitz objectives of this SM-Lux (10x, 40x and 100x) for use with the head and its Leitz eyepieces (as they are corrected for these 160 Leitz objectives)
I also have chinese eyepieces when I want to observe with Leitz head and chinese plan 4x and 10x objectives..... But that's very unfrequent, as I've made this setup almost exclusively for pictures

Milou wrote: ↑

Fri Jan 21, 2022 2:48 pm

Thank's for information about pol. Lomo objectives.

Presently I've chinese cheap plan objectives (4x and 10x) like this: https://www.ebay.fr/itm/324135181148?var=513190400575
As I use them almost exclusively for pictures with my M4/3 on tubes (replacing Leitz SM-Lux head), I think it is perhaps not usually ideal to mix this Lomo with chines ones (they are surely not parfocal!)!
But there are not a lot of cheap plan low magnification objectives at least not in these chinese serie

The plan about 18mm fov you note for this Lomo objective, seems to be small for me !
Perhaps this kind of objective would have a larger one?
CARL ZEISS JENA Polarisant Objectif PLAN 2,5x 0,07 160/- Pol (in ebay offers)

I have no internediary optics between the objective and the camera

I also have the original Leitz objectives of this SM-Lux (10x, 40x and 100x) for use with the head and its Leitz eyepieces (as they are corrected for these 160 Leitz objectives)
I also have chinese eyepieces when I want to observe with Leitz head and chinese plan 4x and 10x objectives..... But that's very unfrequent, as I've made this setup almost exclusively for pictures

An 18mm f.o.v. was a default standard in many W.F. 160mm systems for many years. Some were 19mm ( AO) and then 20mm and now it is moving towards 22mm but those almost always have 30mm optical tubes instead of 23.2mm tubes.

Many microscopes that used the same Chinese objectives as you have would have had an 18mm f.o.v.
Chinese objectives have historically been patterned after existing systems made by one of the Japanese companies, mostly Olympus and Nikon, occasionally another company. It often has to do with which company a specific factory has been contracted to make optics for, which they then produce similar optics to the same corrections. Your objectives would likely be based on a Nikon pattern.
The Lomo objective will be close to being parfocal with your objectives because it , like yours is 45mm D.I.N. but low power objectives often are not perfectly parfocal anyway. A different problem might be that , since you are using direct projection and the Lomo probably needs plan compensating oculars, it likely won't give you a corner to corner plan image, unless your sensor is not capturing the full image circle.
It will be hard for you to find an inexpensive objective to fit your needs, without using an intermediate optic.

https://www.ebay.ca/itm/Nikon-Microscop ... ect=mobile

Hello! The mentioned CZJ Plan 2,5 is designed for 20 mm FOV I believe, it's from Polmi A microscope which was equipped with 10x/20 eyepiece from the factory. I'm really lucky to have one =)
Also it indeed needs plan compensating eyepieces (PK as Zeiss called them at the time).

Dmi3n wrote: ↑

Sat Jan 22, 2022 5:02 am

Also it indeed needs plan compensating eyepieces (PK as Zeiss called them at the time).

Are you sure about the "K" for correction? Many lower power Zeiss Jena objectives were not calculated to be used with correcting eyepieces. I don't know this objective.

This one here wouldn't work in your setup, Milou: https://www.ebay.fr/itm/363614931254
It is definately calculated for the use of plan compensating eyepieces like KPL.

Depending on what you can get locally and what you want to do it might be an option to change the camera setup to be usable for objectives that are calculated to be used with compensating eyepieces. Most 160mm plan objectives on the market are from systems that use compensation.

Rolfs method with KPL 10 - 8 - 10 like described here works well for M4/3: https://microscopyofnature.com/micropho ... -eyepieces

Thank you for information about these plan objectives, very helpful for me, as I'm not involved in microscopy for a long time

Especially the need for compensation eyepiece of these different "cheap" objectives, therefore not convenient for my setup, is really a handicap....

Rolfs method with KPL 10 - 8 - 10 is very interesting indeed (tank you MicroBob for the link) and gives very good results.

But presently I only have a Leitz binocular head.......Perhaps later, if I can find a trinocular one, It would be easier to make another setup as shown in Rolfs method!
These trinocular heads seems to rather expensive and not very frequent....Therefore I think I've to be patient

The trinocular head is not the central part of Rolf's camera adaptation, you cou use it with a mono or bino tube too. What he did is to assemble projectives from eyepiece parts to project a well corrected image directly onto the cameras chip. This projective sits at the given tube length of the microscope, held by whatever tube.

MicroBob wrote: ↑

Sat Jan 22, 2022 7:28 am

Dmi3n wrote: ↑

Sat Jan 22, 2022 5:02 am

Also it indeed needs plan compensating eyepieces (PK as Zeiss called them at the time).

Are you sure about the "K" for correction? Many lower power Zeiss Jena objectives were not calculated to be used with correcting eyepieces. I don't know this objective.

Yes, I am sure about the correction. Polmi A has a set of PK eyepieces (10х 16х and 25x, all widefield PK's).