Quality of Nikon short barrel apo objectives?
Quality of Nikon short barrel apo objectives?
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?
Re: Quality of Nikon short barrel apo objectives?
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.
"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.
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Re: Quality of Nikon short barrel apo objectives?
What does " corrected for field" mean?
Re: Quality of Nikon short barrel apo objectives?
Presumably "curvature of ..."apochronaut wrote:What does " corrected for field" mean?
MichaelG.
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Re: Quality of Nikon short barrel apo objectives?
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,
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,
Re: Quality of Nikon short barrel apo objectives?
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.apochronaut wrote:The statement still seems rather vague . . .,
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.
Re: Quality of Nikon short barrel apo objectives?
PeteM,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.
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.
Re: Quality of Nikon short barrel apo objectives?
Assuming that you are referring to the statement that I quoted [rather than the phrasing of PeteM's original question]:apochronaut wrote:The statement still seems rather vague . < etc. >
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.
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Re: Quality of Nikon short barrel apo objectives?
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.
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.
Re: Quality of Nikon short barrel apo objectives?
So that would be [yes] the statement that I quoted.apochronaut wrote:The quote from the Microscope MIke website, not either of you.
Thanks for the confirmation.
MichaelG.
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