Quality of Nikon short barrel apo objectives?

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
Post Reply
Message
Author
PeteM
Posts: 2982
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Quality of Nikon short barrel apo objectives?

#1 Post by PeteM » Mon Jul 09, 2018 7:51 pm

Does anyone have experience with the older Nikon (S era) short barrel apo objectives? They seem to come up fairly frequently at comparatively low prices. Is this a reflection of shortcomings in correction, field, flatness, contrast, or ?? compared to more modern apo objectives?

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Quality of Nikon short barrel apo objectives?

#2 Post by MichaelG. » Mon Jul 09, 2018 7:59 pm

Sorry, I have no personal experience of them ... but I do recall reading this rather 'teasing' comment :
"Nikon objectives from the 60's and 70's are often of the "S" type, for use with the Model S system, which is characterized by short barrels with short parfocal distances. They are mostly not well corrected for color or field, but there are exceptions."
https://lavinia.as.arizona.edu/~mtuell/ ... tives.html

MichaelG.
Too many 'projects'

apochronaut
Posts: 6269
Joined: Fri May 15, 2015 12:15 am

Re: Quality of Nikon short barrel apo objectives?

#3 Post by apochronaut » Mon Jul 09, 2018 10:18 pm

What does " corrected for field" mean?

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Quality of Nikon short barrel apo objectives?

#4 Post by MichaelG. » Mon Jul 09, 2018 10:54 pm

apochronaut wrote:What does " corrected for field" mean?
Presumably "curvature of ..."

MichaelG.
Too many 'projects'

apochronaut
Posts: 6269
Joined: Fri May 15, 2015 12:15 am

Re: Quality of Nikon short barrel apo objectives?

#5 Post by apochronaut » Mon Jul 09, 2018 11:31 pm

The statement still seems rather vague . There is also coma and lateral ca, across the field. Lack of curvature of field correction would be obvious, if the objectives were not designated as having some degree of planarity. It seems he is talking also about standard achromats.


I have used a few Nikon apochromats in the J.I.S. format, with compensating oculars, and they are about as good as any others, I have used( AO/Spencer,B & L, Olympus, Baker, Lomo, all short tube non-plan apochromats).....made before the jump to plan and wider fields, necessitated larger objective barrels. Nikon, also used coatings rather early on so I recall the contrast to be pretty good. All of the older apochromats are way better for fine imaging than, something like brand new achromats but they must have matching compensating oculars, not just compensating oculars, matching compensating oculars. The field of view is a little restricted with 10x compens but it was common with Spencer and B &L to use 15X compens oculars as the default ocular, rather than 10X because of the higher N.A. of the objectives. Thus, the 15X , usually had a wider f.n. I would be surprised if Nikon did not follow with that,

PeteM
Posts: 2982
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: Quality of Nikon short barrel apo objectives?

#6 Post by PeteM » Tue Jul 10, 2018 12:02 am

apochronaut wrote:The statement still seems rather vague . . .,
It was vague, sorry (the statement about corrected for field, followed by flatness). I was thinking of field coverage and then plan flatness within that field.

I own a couple Nikon CF fluor lenses (160mm tube) which are excellent to my eye. How would an older Nikon short body Apo (likely at a lower price) compare in all the various aspects . . . I'm guessing the older Apos have maybe only a 16mm field, not very flat within it, but very good color correction, and (I'd assumed before your comment) not very good contrast. I do have some Nikon short body phase achromat lenses and can say the phase effect is very good.

User avatar
zzffnn
Posts: 3200
Joined: Sat Jun 20, 2015 3:57 am
Location: Houston, Texas, USA
Contact:

Re: Quality of Nikon short barrel apo objectives?

#7 Post by zzffnn » Tue Jul 10, 2018 12:41 am

PeteM wrote:.......

I own a couple Nikon CF fluor lenses (160mm tube) which are excellent to my eye. How would an older Nikon short body Apo (likely at a lower price) compare in all the various aspects . . . I'm guessing the older Apos have maybe only a 16mm field, not very flat within it, but very good color correction, and (I'd assumed before your comment) not very good contrast. I do have some Nikon short body phase achromat lenses and can say the phase effect is very good.
PeteM,

If your Nikon CF fluor objectives are those 45mm parfocal ones, then I suspect they will image better overall than short Nikon S apos. I too suspect less field flatness, smaller field width and less contrast. Really don't know about CA correction.

Between a modern Nikon 45mm E Plan 40x NA 0.65 (budget CF achromats) and my short LOMO apo 40x NA 0.95, I surely prefer the LOMO (though I mostly prefer to trade field flatness and field number for central resolution). It is not a fair comparison though, as LOMO have much higher NA, and I almost always use contrast-enhancing oblique and darkfield illumination (which compensate any lack of contrast from objectives).

I doubt short S apos can even touch modern apos, otherwise most hobbyists would have rushed to buy out those much cheaper S apos.

Best to ask Mike himself over his web page; though I suspect he was talking about model S achromats.

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Quality of Nikon short barrel apo objectives?

#8 Post by MichaelG. » Tue Jul 10, 2018 6:12 am

apochronaut wrote:The statement still seems rather vague . < etc. >
Assuming that you are referring to the statement that I quoted [rather than the phrasing of PeteM's original question]:
Yes, it's vague, and to a large extent that's why I quoted it!
Its very vagueness suggested that PeteM might have considerable difficulty finding authoritative answers to his question.

I have contributed what [very] little I can to the discussion, and there is really no point in me trying to debate the merits of something I have never used! ... I certainly cannot explain what some stranger had in mind when he wrote a short, and rather cryptic, sentence.

As you have some personal experience of these objectives ... I hope to benefit from that.

MichaelG.
Too many 'projects'

apochronaut
Posts: 6269
Joined: Fri May 15, 2015 12:15 am

Re: Quality of Nikon short barrel apo objectives?

#9 Post by apochronaut » Tue Jul 10, 2018 2:29 pm

The quote from the Microscope MIke website, not either of you. He didn't identify what class of objectives he was referring to and terms such as , corrected for field, are vague. It certainly doesn't seem like he is referring to Nikon apochromats, more likely achromats. Typically older apochromats, irregardless of make and even very old ones, have superior correction for all aberrations across the field, with much flatter fields than contemporary achromats. In use, one settles in to the 14 or so f.n. older objectives provide rather quickly and the deficiency is noticed only comparatively, if one moves over to a modern 20mm field microscope dramatically. The high resolution and colour correction to the edge of the field puts them in a class of their own, well above all but the best even modern planachromats. I've used 3mm .95 oil immersion apochromats made in the 1920's and at least one 3mm 1.0 oil planachromat from 60 years later and the apochromats were so superior, that in comparison one might think the achromat was defective, which it wasn't.

The Nikons, I have used in the past were a 10x .30, 40x( can't remember the aperture) and a 100x 1.4 oil but with matching oculars and they seemed as good as any. Where the use of older apochromats falls off the rails is when users fail to ensure to match of the oculars with the correct compens eyepieces. All of a sudden an apochromat isn't an apochromat any more. Most modern apos do not need compens oculars anymore. Possibly Lomo, still but I don't know for sure.

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Quality of Nikon short barrel apo objectives?

#10 Post by MichaelG. » Tue Jul 10, 2018 2:54 pm

apochronaut wrote:The quote from the Microscope MIke website, not either of you.
So that would be [yes] the statement that I quoted.

Thanks for the confirmation.

MichaelG.
Too many 'projects'

Post Reply