Can't focus new 60X objective

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Stomias
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Can't focus new 60X objective

#1 Post by Stomias » Mon Apr 19, 2021 6:44 pm

Bought a 60X objective. It is much shorter than my 100x and 40x objectives. I cannot reach focus with it. I cannot even raise my stage high enough to get close to focusing it. It is about the same size as my 4x but the distance from the objective to the slide for focus on the 4x is much longer. Any Ideas how to fix this problem?

LouiseScot
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Re: Can't focus new 60X objective

#2 Post by LouiseScot » Mon Apr 19, 2021 7:08 pm

Stomias wrote:
Mon Apr 19, 2021 6:44 pm
Bought a 60X objective. It is much shorter than my 100x and 40x objectives. I cannot reach focus with it. I cannot even raise my stage high enough to get close to focusing it. It is about the same size as my 4x but the distance from the objective to the slide for focus on the 4x is much longer. Any Ideas how to fix this problem?
Hi

More details needed, really. What microscope and exactly which 60x are you talking about? You may just need some parfocal extenders.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Stomias
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Re: Can't focus new 60X objective

#3 Post by Stomias » Mon Apr 19, 2021 7:58 pm

Reichert Microstar IV scope. Cheap Chinese objective no name 60X. Markings S60/0.85 160/0.17 $17.90 free shipping :O

Hobbyst46
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Re: Can't focus new 60X objective

#4 Post by Hobbyst46 » Mon Apr 19, 2021 8:29 pm

From your description, you bought a short-barrel objective, with a parfocal distance of possibly 33-36mm, whereas your other objectives are possibly 45mm parfocal distances. For example, 60x and 100x objectives and even the 40x objective, that are compatible with each other focus-wise, are of nearly the same length. The 4x objective is shorter because its working distance is much larger.

A possible solution is an extender, but it would probably better to try and return the 60x objective and buy a new, compatible one instead.

BramHuntingNematodes
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Re: Can't focus new 60X objective

#5 Post by BramHuntingNematodes » Mon Apr 19, 2021 8:31 pm

Ah Stomias! That 160 refers to a tube length. That is not a compatible objective for a Microstar! Microstars need that infinity symbol. Even then, your Olympus or Zeiss infinity-corrected lenses probably aren't going to look quite right either. Someone with a lot of experience can elaborate on what lenses besides the Reichert/ AO/ Leica infinity might work, but that's all I have seen on that scope.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

LouiseScot
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Re: Can't focus new 60X objective

#6 Post by LouiseScot » Mon Apr 19, 2021 8:41 pm

BramHuntingNematodes wrote:
Mon Apr 19, 2021 8:31 pm
Ah Stomias! That 160 refers to a tube length. That is not a compatible objective for a Microstar! Microstars need that infinity symbol. Even then, your Olympus or Zeiss infinity-corrected lenses probably aren't going to look quite right either. Someone with a lot of experience can elaborate on what lenses besides the Reichert/ AO/ Leica infinity might work, but that's all I have seen on that scope.
I think older Microstars are finite tube length?

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Can't focus new 60X objective

#7 Post by BramHuntingNematodes » Mon Apr 19, 2021 8:53 pm

Could be, but the forum-popular model IV is not.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

apochronaut
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Re: Can't focus new 60X objective

#8 Post by apochronaut » Mon Apr 19, 2021 9:05 pm

That objective is for a Chinese short barrel microscope with a 160mm tube length. They made them up until the 80's as lab grade microscopes but still offer them for sale, since some of the old designs are still made for student microscopes. They have a lot of kids to teach.

There has been so much info. written on this forum about infinity correction vs. fixed tube and the various parfocal systems including the 45mm D.I.N. system. That's why I occasionally raise the issue of why this forum isn't properly organized with a group of stickies available for reference.
It is sorely lacking.

You are correct, Louise. Microstar was an AO model going back to the introduction of the series 4 in 1956. That stand existed for about 6 or 7 years only. Subsequent infinity corrected models, the 10, 110 and 410 were also called Microstars. You don't see the term Microstar I, II or III, normally it is series 10 Microstar etc. but when the series 400 came out they dubbed it Microstar IV, which is what Stomias is trying to retrofit.

There is a Chinese infinity corrected planachro 60X .80 objective , probably based on an Olympus design. It works on a Microstar IV and can be easily made parfocal but I found the contrast and resolution of that objective a little too low, compared to using the correct 15X eyepieces with the 40X .70 planfluor, which I normally use. It magnifies a little high, around 67X if I recall, correctly.

I haven't compared it exhaustively with the 40X .66 planachro + 15X. I should.

The seller is reliable and it is cheaper now than when I bought it 4 years ago. https://www.ebay.com/itm/Microscope-Obj ... SweqdeZzgu
Last edited by apochronaut on Mon Apr 19, 2021 9:29 pm, edited 1 time in total.

Stomias
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Re: Can't focus new 60X objective

#9 Post by Stomias » Mon Apr 19, 2021 9:06 pm

My objectives are marked with an infinity sign. If I buy extenders and I get it close to the length of the 40x and 100x will it work? I'll eat what I paid as I won't ship it back to China. I see 3mm extenders that can be stacked.

LouiseScot
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Re: Can't focus new 60X objective

#10 Post by LouiseScot » Mon Apr 19, 2021 9:13 pm

Stomias wrote:
Mon Apr 19, 2021 9:06 pm
My objectives are marked with an infinity sign. If I buy extenders and I get it close to the length of the 40x and 100x will it work? I'll eat what I paid as I won't ship it back to China. I see 3mm extenders that can be stacked.
In that case you need an infinity objective (as Bram said!). I don't know about compatibility with 'generic' infinity objectives. I'm sure there are lots of nice people on here who can advise :)

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: Can't focus new 60X objective

#11 Post by apochronaut » Mon Apr 19, 2021 9:33 pm

Yes. Your objectives are infinity. That's why that one doesn't work. Don't waste your money on parfocalizing shims. The image will be terrible when you do get it in focus.

Stomias
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Re: Can't focus new 60X objective

#12 Post by Stomias » Mon Apr 19, 2021 9:47 pm

Thanks all, for enlightening me. I'm not usually one to just buy something without researching....This time I did though. I never use my 100x oil immersion so I thought the 60 would get used.....

LouiseScot
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Re: Can't focus new 60X objective

#13 Post by LouiseScot » Mon Apr 19, 2021 10:12 pm

Stomias wrote:
Mon Apr 19, 2021 9:47 pm
Thanks all, for enlightening me. I'm not usually one to just buy something without researching....This time I did though. I never use my 100x oil immersion so I thought the 60 would get used.....
Hi

It's worth taking the time to read through some of the extensive online resources e.g. https://www.microscopyu.com/microscopy-basics

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Stomias
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Re: Can't focus new 60X objective

#14 Post by Stomias » Mon Apr 19, 2021 11:06 pm

I've come to the "end" of the internet several times in my long life Louise :)

LouiseScot
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Re: Can't focus new 60X objective

#15 Post by LouiseScot » Mon Apr 19, 2021 11:39 pm

Stomias wrote:
Mon Apr 19, 2021 11:06 pm
I've come to the "end" of the internet several times in my long life Louise :)
You can always go back to the beginning :) Keep studying and learning - it's good for you!
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Stomias
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Re: Can't focus new 60X objective

#16 Post by Stomias » Mon Apr 19, 2021 11:55 pm

Ha!!!

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mrsonchus
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Re: Can't focus new 60X objective

#17 Post by mrsonchus » Tue Apr 20, 2021 12:25 am

apochronaut wrote:
Mon Apr 19, 2021 9:05 pm
.............deletion for brevity only..................

There is a Chinese infinity corrected planachro 60X .80 objective , probably based on an Olympus design. It works on a Microstar IV and can be easily made parfocal but I found the contrast and resolution of that objective a little too low, compared to using the correct 15X eyepieces with the 40X .70 planfluor, which I normally use. It magnifies a little high, around 67X if I recall, correctly.

I haven't compared it exhaustively with the 40X .66 planachro + 15X. I should.

The seller is reliable and it is cheaper now than when I bought it 4 years ago. https://www.ebay.com/itm/Microscope-Obj ... SweqdeZzgu
True - I have one and it's really very good indeed - see a post I made comparing it with an Olympus planopochromatic 0.90 60x high-dry objective with correction-collar it did rather too well for comfort!!
John B

apochronaut
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Re: Can't focus new 60X objective

#18 Post by apochronaut » Tue Apr 20, 2021 1:56 am

One of my big problems with the objective was how far out of center it was ; 200 microns or so. The high magnification Reichert objectives are rarely out by 20. Nevertheless for 80 bucks it was o.k. I guess but I just spent 125.00 for a 40X 1.0 oil planapo. If I put 15X eyepieces on that, it makes the 60X .80 seem like it has been smeared with vaseline and pointing in the wrong direction to boot.

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