180mm ED Nikkor 2.8 as tube lens?

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WaldenKirsch
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180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

i’m considering picking up a nikon or mitutoyo 10x plan infinity objective… would like to use in conjunction with my nikkor 180mm ED 2.8 as a tube lens… all on my nikon Z7 with the usual Z adapter. is there any reason why this optical system, and in particular the nikkor 180 as a tube lens, would -not- work, except for the slight reduction in nominal objective magnification due to the 180mm vs 200 length of the tube lens? this is for extreme macro work: imaging micrometeorites. will be using my stackshot rail at likely single-digit micron steps to focus stack approx 250micron subjects. input/suggestions/ideas/alternatives greatly appreciated:)

Adalbert
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by Adalbert »

Hello WaldenKirsch,
I use Canon EF100mm and EF200mm as tube lenses with the Mitu 10x and the EOS 6D.
So I would say that 180mm should work in your case.
Best , ADi

WaldenKirsch
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

ah, good to know adalbert…thank you very much.

rjlittlefield
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by rjlittlefield »

With the Z7 in full frame mode, the Nikkor may introduce some vignetting. I do not know that lens in particular, but in general Nikon long lenses seem more vulnerable than Canon to vignetting when used with microscope objectives. If it does occur, then switching to a Raynox DCR-150 as tube lens will solve the problem for a few dollars.

In any case, I expect that vignetting will not be a problem for your application, because at 10X, a 250 micron subject becomes only 2.5 mm on sensor. Edges and corners will not be needed unless you're photographing an array of them.

I would not be surprised if you soon find yourself wanting a 20X or even 50X objective, to fully appreciate the details of such small subjects.

--Rik

WaldenKirsch
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

hi rik,
really appreciate the info…you nailed it.
vignetting is not really an issue in my application… since i only really care about a relatively small object that i’m shooting in the dead-center of the frame.
and your suggestion wrt a higher-magnification objective (20x or even 50x)…is exactly what i’m weighing. a 10x objective is not really going to me the head-and-shoulders tite shots of the approx 250 micron micrometeorite subjects i want to shoot.
however i’m not sure i’m ready yet to drop several grand on a mity objective of this kind.
in this regard, 2 questions: 1. do you know if anyone -rents- objectives? i’d be more willing to purchase a spendy objective like this if i were able to test-drive it first. 2. everything i read suggests that the mity products outperform nikon’s in nearly all respects (tho obviously at a steeper price.) any perspective on this?
thanks very much!

rjlittlefield
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by rjlittlefield »

I fully agree that the Mitutoyo M Plan Apo objectives are better than anything else in their price bracket. But they are definitely pricey. They are also relatively fragile so used units must be purchased with return rights and careful testing immediately after delivery. I do not know anybody who rents objectives like this.

One alternative that might work for you is the Nikon CF Plan 50X NA 0.55 inf/0 EPI ELWD (8.7 mm). These run about $600 on eBay and are commonly available. (I see a couple offered at this time.)

The biggest drawback to the Nikon 50X is that it has quite a bit of longitudinal CA, which introduces color casts especially in out-of-focus regions. These may or may not be acceptable for your application. For a subject with some similarities to yours, see viewtopic.php?t=15581 , including in particular the post at viewtopic.php?p=99228#p99228 .

--Rik

Scarodactyl
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by Scarodactyl »

It really depends how much working distance you need for your illumination. Nikon doesn't really make objectives in mitutoyo's niche (with a few minor exceptions), nothing with the combination of color correction, working distance and large field coverage. But if you don't need gigantic field coverage or extremely long working distances there are lots of good Nikon options which will also have higher resolution.
With such small subjects you might get away with quite short working distances, maybe even around 1mm(?). That puts you into the range of traditional metallurgical objectives which will often be cheaper.
Edit: was writing when the above post went up

WaldenKirsch
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

rik and scarodactyl,
appreciate both of your suggestions/experience.
i’d obviously like avoid any serious CA… i like to hand off to helicon focus stacked images that are as clean and crisp and free of aberrations as possible… lest i spend way more time than i want in post-processing to reduce artifacts.
and 1mm working distance is getting kind of close for me… to light these little guys correctly i’m going to need a bit more elbow room.
i guess i’ll have to go out and buy an SEM:) (and forget about retiring!)
thanks again for your help…much appreciated.
walden kirsch.

Lou Jost
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by Lou Jost »

I do use the 180 ED (non-IF), which has a great reputation especially in astrophotography. I think I have included it in one of my past tube lens tests on this forum, but I don't know where it is. I think you should try it before you spend money on something else.

WaldenKirsch
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

hi lou,
yes... the nikkor 180 2.8 is a good high quality prime...
i'll certainly give it a try before i buy a special-purpose tube lens.
thanks for the info.
walden kirsch

rjlittlefield
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by rjlittlefield »

Lou Jost wrote:
Sat Jul 17, 2021 7:25 pm
I do use the 180 ED (non-IF), which has a great reputation especially in astrophotography. I think I have included it in one of my past tube lens tests on this forum, but I don't know where it is.
viewtopic.php?p=228350#p228350 ?

--Rik

WaldenKirsch
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by WaldenKirsch »

thanks, rik:)

Lou Jost
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Re: 180mm ED Nikkor 2.8 as tube lens?

Post by Lou Jost »

Rik, thanks, yes that must be it. I see that this was on MFT so may be of little relevance here.

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