Nikon Plan objective - washed out colours

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pippo1234
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Nikon Plan objective - washed out colours

#1 Post by pippo1234 » Mon Apr 12, 2021 5:17 pm

Hi,

I have bought a Nikon Plan (old chrome) 10x/0.25 160/- on eBay. A few minor scratches on the lens, not visible in use, but... color rendition is way off. Colors are washed out compared to all my other objectives. Detail resolution is fine though. What can be the reason? The seller has promptly refunded me, but I would like to understand.

TIA

BramHuntingNematodes
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Re: Nikon Plan objective - washed out colours

#2 Post by BramHuntingNematodes » Mon Apr 12, 2021 5:54 pm

Peek into the objective with a stereoscope never know what you'll find--cracks, mold, spiders, who knows
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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Rossf
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Re: Nikon Plan objective - washed out colours

#3 Post by Rossf » Tue Apr 13, 2021 3:17 am

Sometimes even nematodes!

pippo1234
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Re: Nikon Plan objective - washed out colours

#4 Post by pippo1234 » Tue Apr 13, 2021 8:26 am

No life forms, cracks or mould inside. 5-6 scratches on the front lens but not visible in operation.

I attach a picture of the lens. I wonder if it's of an age before Nikon dropped color correction through matched eyepieces.

In the meantime, I got an Olympus Splan whose quality amazes me. I am tempted to gradually move to all Splans even if this requires changing at least my Nikon relay lens (the scope is a Labophot 2) to an Olympus one.

Thanks!

Image

apochronaut
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Re: Nikon Plan objective - washed out colours

#5 Post by apochronaut » Tue Apr 13, 2021 10:41 am

All microscope objectives used properly in a coherent system made during any era of manufacturing by reputable companies have fairly equivalent performance. There are differences between them but it is quite subtle. One manufacturer might show slightly lower saturation of red for instance but have higher saturation of green. Sometimes , one mfg. will have slightly lower contrast than a competitor only to leapfrog them in their next generation of lenses and so forth. It has been a fairly continuous development based on technical understanding being realized through improvements in the materials available; glass mostly. No company could produce an inferior product find a market for it and still be around.
When an example of an objective shows up that produces an image of dramatically lower quality, it is either defective or the objective is being utilized in a manner it is unsuited to.
I think you will find that the objective has a serious defect which could be one of four things or a combination of. It has an undetected problem in a cement layer causing a loss of contrast. It has a layer of some type of hard to see film on one or more of the lens surfaces, also causing a loss of contrast . It has been disassembled in the past and the shimming that determines the lens spacing has not been observed causing spherical aberration. It has a degraded interior damping and or a missing rear diaphragm, causing internal reflection and flare. I have never seen the latter cause sufficient flare to push an objective over the cusp of being outright bad but maybe with some it could.

You did not say what system you are using the objective in? Some objectives require further compatible optics further downstream in order to perform properly.

pippo1234
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Re: Nikon Plan objective - washed out colours

#6 Post by pippo1234 » Tue Apr 13, 2021 11:17 am

Thanks! That's most helpful to further my understanding which was the main reason to ask (the seller refunded the cost and told me to keep the objective).

I have a Labophot 2, with 4 Achro objectives (10x and 40x being phase contrast) + 2 plan (20x, 40x) objectives. All of them are from Nikon and have basically identical color rendition. The 10x plan in question is an obvious outlier and this made me think something was wrong with it.

I'd love to (and will) compare a Nikon 10x plan with the 10x Olympus SPlan. I would definitely like to stick with Nikon if performance is comparable to the Splan.

LouiseScot
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Re: Nikon Plan objective - washed out colours

#7 Post by LouiseScot » Wed Apr 14, 2021 11:55 pm

pippo1234 wrote:
Tue Apr 13, 2021 11:17 am
Thanks! That's most helpful to further my understanding which was the main reason to ask (the seller refunded the cost and told me to keep the objective).

I have a Labophot 2, with 4 Achro objectives (10x and 40x being phase contrast) + 2 plan (20x, 40x) objectives. All of them are from Nikon and have basically identical color rendition. The 10x plan in question is an obvious outlier and this made me think something was wrong with it.

I'd love to (and will) compare a Nikon 10x plan with the 10x Olympus SPlan. I would definitely like to stick with Nikon if performance is comparable to the Splan.
If you're using finite Nikon objectives I'd recommend sticking to their CF range if you don't need/use additional colour correction. I believe the Labophot was designed to use the CF objectives. I use them on my Swift 380T - they are great.

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: Nikon Plan objective - washed out colours

#8 Post by PeteM » Thu Apr 15, 2021 12:46 am

Nikon "CFN" plan achromat finite objectives are equivalent to Olympus S Plan and available used at around the same prices. Ditto the plan apo. These have three heavy knurled rings on the chrome color body and slightly higher numerical apertures than Nikon's lesser plan achromats in all but the 100x. You might look for those as they will be entirely consistent with what you have and not need matching corrective eyepieces.

pippo1234
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Re: Nikon Plan objective - washed out colours

#9 Post by pippo1234 » Thu Apr 15, 2021 5:37 am

Nikon "CFN" plan achromat finite objectives are equivalent to Olympus S Plan and available used at around the same prices. Ditto the plan apo. These have three heavy knurled rings on the chrome color body
That’s most helpful. Thanks! I am kind of clueless about how to distinguish the various historical Nikon ranges and their respective features, apart from what is written on the lens, which is less informative than in the Olympus range (eg only Plan vs SPlan/Mplan). I have not been able to find a source of comprehensive classification comparable to Alan Wood’s pages on Olympus.

LouiseScot
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Re: Nikon Plan objective - washed out colours

#10 Post by LouiseScot » Thu Apr 15, 2021 8:36 am

pippo1234 wrote:
Thu Apr 15, 2021 5:37 am
Nikon "CFN" plan achromat finite objectives are equivalent to Olympus S Plan and available used at around the same prices. Ditto the plan apo. These have three heavy knurled rings on the chrome color body
That’s most helpful. Thanks! I am kind of clueless about how to distinguish the various historical Nikon ranges and their respective features, apart from what is written on the lens, which is less informative than in the Olympus range (eg only Plan vs SPlan/Mplan). I have not been able to find a source of comprehensive classification comparable to Alan Wood’s pages on Olympus.
Here you go https://krebsmicro.com/Nikon_CF.pdf

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

pippo1234
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Re: Nikon Plan objective - washed out colours

#11 Post by pippo1234 » Thu Apr 15, 2021 11:08 am

Thanks Louise! That's most helpful.

The type of objective in the picture I posted (all my Nikon plans are in that style) is not included. I am not sure whether they are older. From the linked brochure, I am not even sure they are CF. My non-plan achro objectives (I guess they are subsequent to that brochure) are black and from reading the brochure I am starting to doubt they have full spectrum colour correction at all (which I originally thought they had).

apochronaut
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Re: Nikon Plan objective - washed out colours

#12 Post by apochronaut » Thu Apr 15, 2021 11:55 am

No achromat has full spectrum colour correction. In fact, no objective has full spectrum colour correction. If achromats could do it, then fluorite and apochromat objectives wouldn't exist and even they are on a never ending treadmill leading to perfection somewhere near to infinity. Companies will tell you their objectives are better than the competition in order to sell product but they are twisting the truth. What are they going to do, tell you they are lousy?
Achromats are corrected at two colours of the spectrum, red and blue for axial ca, which means that the other colours only have a degree of correction with the colour directly intermediate, the least corrected. They are also corrected for spherical aberration at green. CF objectives are probably further provided with colour corrections off axis, so Nikon can claim to have a more complete correction in the objective but an achromat is an achromat. Whether an objective has more complete native corrections is a moot point in an achromat microscope because all quality microscopes are made to provide corrections consistent with the type, by the time the image gets to the eye anyway. The axial corrections are pretty similar and you can put the lateral corrections in the barrel or in the telan lens or in the eyepiece for that matter. The end result is the same or very similar within an era. For people using an objective mounted directly on a camera, a more completely corrected objective is paramount, so the importance of a fully corrected microscope objective is more for macro-photography than microscopy.

Fluorites are corrected at 2 or 3 colours and the same for s.a. Apochromats at usually 4 colours or maybe 5 with some of the newer elite apos. 4 or 5 for sa.

LouiseScot
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Re: Nikon Plan objective - washed out colours

#13 Post by LouiseScot » Thu Apr 15, 2021 11:58 am

pippo1234 wrote:
Thu Apr 15, 2021 11:08 am
Thanks Louise! That's most helpful.

The type of objective in the picture I posted (all my Nikon plans are in that style) is not included. I am not sure whether they are older. From the linked brochure, I am not even sure they are CF. My non-plan achro objectives (I guess they are subsequent to that brochure) are black and from reading the brochure I am starting to doubt they have full spectrum colour correction at all (which I originally thought they had).
I'd say the objective pic you posted indicates it's older than the Nikon CF / CF N range. My goto for reminding me of the meaning of objective markings is here: https://www.microscopyu.com/microscopy- ... ifications but older objectives may not conform.

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

microcosmos
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Re: Nikon Plan objective - washed out colours

#14 Post by microcosmos » Tue Jul 06, 2021 2:45 am

LouiseScot wrote:
Thu Apr 15, 2021 11:58 am
I'd say the objective pic you posted indicates it's older than the Nikon CF / CF N range. My goto for reminding me of the meaning of objective markings is here: https://www.microscopyu.com/microscopy- ... ifications but older objectives may not conform.
Louise
What's the difference between "CF" and "CF N", if "N" means normal field of view? Do the CF (non-N) objectives have some other field of view? I can't find an explanation anywhere, not even in Nikon's original 1989 brochure for these objectives. In the brochure, CF and CF N ratings are assigned to objectives of different magnifications so I can't directly compare the NA and other specifications.

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Re: Nikon Plan objective - washed out colours

#15 Post by viktor j nilsson » Tue Jul 06, 2021 4:14 am

CFN = CF New. Nikon gradually updated the lens designs of the original CF series, calling the updated versions CFN (NCF in Japanese literature). They didn't change all at once, which is why you see a combination of CF and CFN objectives in the catalogue. Some designs were never changed before the shift to infinity optics, for example the 40x 1.00 CF planapo.

microcosmos
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Re: Nikon Plan objective - washed out colours

#16 Post by microcosmos » Tue Jul 06, 2021 5:03 am

Thank you! That solves a mystery for me.

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