What microscopes have the same illuminator lens as the Nikon e400?

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farnsy
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What microscopes have the same illuminator lens as the Nikon e400?

#1 Post by farnsy » Sun Jul 25, 2021 1:22 am

I recently picked up a Nikon e400 that's missing the lens over the illuminator. Whoops. This is sometimes called the "field lens." It's the last piece of glass the light goes through before it goes to the condenser and on this microscope is a thick disk.

Image

I'm looking to source a replacement. The field diaphragm and mirror are fine but the final glass piece is missing (also the plastic ring that spins but I can 3D print a solution for that if needed). I don't want to buy another whole microscope body if I can avoid it, but if so I'd like it to be a cheaper one.

So my question for anyone who knows is which microscopes use this same illuminator lens? I'm sure the e600 does as the two scopes have almost everything else in common. How about the e200 or e100? Or the e50i? It's cheaper to get parts for those scopes.

I saw a labophot 2 field assembly on ebay for not too much, and it actually looks just right, but it's a different generation of microscopes so I am skeptical about whether it is worth pursuing.

What do you think? Anyone have a Nikon corpse from this generation you could check out or even salvage from?

Phill Brown
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#2 Post by Phill Brown » Sun Jul 25, 2021 9:01 am

Nikon do a lot of modular design.
If the part from a labophot 2 fits it's a good probability it's the same part used.
I have a Donor/scrap Labophot 2 base could take apart for more info.
Looking at an e400 it's not identical/same part exactly.
Labophot iris markings are printed instead of moulded.

farnsy
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#3 Post by farnsy » Sun Jul 25, 2021 9:34 am

There is a youtube video in which the video maker disassembles this part and pulls out the lens. If you get a chance and are willing, I wonder if you could do what he does between 6:05 and 7:38 and tell me if it all looks the same where it counts. That would give me confidence to pick up the Labophot 2 assembly. It's a reasonable amount of money to risk on a hunch.

My alternative is to pick up an e600 body for 25x as much, which would work for sure but it would result in an extra body floating around my house after I've extracted the parts I want. I already have lots of microscope bodies around, unfortunately.

Although, I'm also slightly interested in the e600 nosepiece dovetail. The e400 and e600 have the same body but different turret attachments, with the e400 being more difficult to remove and has a nosepiece with only 5 positions. The e600 higher models from the time have a nosepiece that slides on a dovetail from the front. I have an extra 6-position nosepiece from my other microscope (the same scope as the AccuScope EXC-500). That scope is Nikon compatible in many ways including having compatible objectives and a head that is completely compatible from what I can tell (I switched heads and they both worked great). It has the same type of slide-in dovetail as the e600, e800, e1000, 50i, but I don't know if it's the same size. My dovetail is 40mm across. I know the new Ci dovetail is 50mm. I can't find any reference anywhere for the width of the nosepiece dovetail on this generation of Nikon. If it's 40mm, I may just shell out for the e600 body. If not, I may do the work to model and 3d print my own 40mm nosepiece dovetail that can connect to a Nikon e400 body.

If anyone has a Nikon e600, e800, e1000, or 50i and you are willing, I would really appreciate you measuring the nosepiece dovetail and letting me know the width.

Phill Brown
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#4 Post by Phill Brown » Sun Jul 25, 2021 10:07 am

Hi, Are you asking for the dimensions of the lens only?.
Picture is missing the iris adjuster complete assembly?
YouTube video of wiping a first surface mirror before even blowing dust off is sub optimal.
Any contact should be a last resort.
Mirror alignment is critical if removed with some small adjustment built in to most parts.

farnsy
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Location: Fort Worth, Texas

Re: What microscopes have the same illuminator lens as the Nikon e400?

#5 Post by farnsy » Sun Jul 25, 2021 7:30 pm

I'm most concerned about the size and shape of the optic that he removes. That's what I'm missing. I don't know that dimensions will help since I don't have his, but if it looks the same to you, that's good for me. My mirror, iris, and assembly are in good condition and the ring that engages with the iris gear is easily replicated, so I'm not too worried about that.

The dimensions of the assembly might be a good thing to look at. I was thinking of measuring from the assembly to the diffuser that, I would guess, acts as the light source for Kohler illumination purposes. What do you think?

hans
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#6 Post by hans » Sun Jul 25, 2021 8:30 pm

If I understand correctly from the video the field iris is in the base before the mirror in the light path? If so what matters is the distance lens to iris relative to the focal length of the lens. Since it is a relatively modern microscope I would guess the iris is placed one focal length away so the image of the iris is projected at infinity to an infinity-corrected condenser. With the wrong focal length lens the working distance between the condenser and slide will be incorrect (or maybe hit the slide) when the field iris focused in the object plane by adjusting condenser height, as in the usual Köhler setup procedure, and I imagine there would be some loss of light at the extremes of illuminated field diameter and NA.

farnsy
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#7 Post by farnsy » Sun Jul 25, 2021 9:54 pm

That makes OK sense to me.

Here is a photo of the innards

Image

There is a glass lens right by the light source, then two thin plastic disks, then at the beginning of the field assembly is the aperture (before the mirror, as you say). I'm under the impression that the distance that matters is between the second plastic disk and the iris, right?

I'm not actually sure what the role of each of the lenses and disks in the light path are, unfortunately. On some microscopes, the last piece of glass is just a flat pane but on this one it is a thick lens, apparently.

Does the labophat 2 look pretty much like this?

hans
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#8 Post by hans » Sun Jul 25, 2021 10:43 pm

Going back briefly to your earlier post:
farnsy wrote:
Sun Jul 25, 2021 7:30 pm
...diffuser that, I would guess, acts as the light source for Kohler illumination purposes.
There are a lot of discussions around whether a particular location (filament, diffuser, field iris, etc.) can be thought of as "the" illumination source. For systems like this (sometimes referred to as "modified Köhler") where the diffuser is relatively weak (looking through it you see a blurry view of the light source, not a uniform disk of light) I think question is not really well-defined without going into a lot of technical detail and mostly just leads to confusion.

In the original design the focal length of that lens is of course related to all the other dimensions in the illumination including the one you mention:
farnsy wrote:
Sun Jul 25, 2021 9:54 pm
I'm under the impression that the distance that matters is between the second plastic disk and the iris, right?
But for simplicity I suggest focusing on understanding how the field iris ends up imaged in the object plane (and ignoring everything before the field iris) since that is probably the most obvious side effect of removing/changing the field lens. I don't know but would strongly suspect the condenser is infinity-corrected (maybe someone else can confirm) in which case the focal length of the field lens will be approximately equal to the distance from the lens to the field iris so that the image of the field iris is projected at infinity between the lens and condenser. I believe that is why some manufacturers refer to it as the field lens. May also help to think by analogy with the objective side of an infinity-corrected microscope mirrored below the specimen: [condenser, field lens, field iris plane] correspond to [objective, tube lens, intermediate image plane].

hans
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#9 Post by hans » Mon Jul 26, 2021 1:38 am

How does the e400 behave without the lens? I just tried removing the lens from a Reichert Microstar IV. (AO/Reichert call it the collimator in patents, rather than field lens.) The field iris can still be focused by lowering the condenser until there is ~1.4 mm gap between the top lens and slide which is consistent with measurements of EFL of the collimator and condenser I made a while ago: https://www.microbehunter.com/microscop ... =5&t=10709 (Normally the gap is quite small, hard to measure but I would guess around 0.2 mm.) With the lens removed the magnification of the field iris is also noticeably reduced, didn't measure carefully but looked roughly 1/2 the original size, and cannot fill the 4X field even fully open.

From your photo it looks like the e400 is a similar design. If yours has a similar ~1.4 mm condenser-slide gap with the lens missing then it is probably safe to assume it is infinity-corrected and you could try measuring distance from field iris to lens position and buying a lens with that focal length from Surplus Shed or wherever.
farnsy wrote:
Sun Jul 25, 2021 9:54 pm
I'm not actually sure what the role of each of the lenses and disks in the light path are, unfortunately. On some microscopes, the last piece of glass is just a flat pane but on this one it is a thick lens, apparently.
With flat glass window, If the field iris is right behind it, then the condenser is finite-corrected and images the field iris directly, like the AO 10 illuminators for example. Could also be infinity-corrected where the collimator is placed earlier after the field iris but before the mirror like in the 1130 illuminator for the AO 110.

farnsy
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#10 Post by farnsy » Mon Jul 26, 2021 2:08 am

hans wrote:
Mon Jul 26, 2021 1:38 am
How does the e400 behave without the lens?
Unfortunately the transformer is not working, so I have not yet evaluated the image--I'm intending to rig LED illumination for this scope (or an e600, if I buy one). I could shine a flashlight back there, but I'm not sure that will tell us what we want to know as it won't necessarily look the way it would have looked if the missing lens was the only issue. In addition, the very first piece of glass in the illumination train has a significant piece broken off, so I'm not sure a small source located where the original bulb went will be that good either. Of course, the e600 doesn't have that piece at all as it would be built in to the illumination housing.
With flat glass window, If the field iris is right behind it, then the condenser is finite-corrected and images the field iris directly, like the AO 10 illuminators for example. Could also be infinity-corrected where the collimator is placed earlier after the field iris but before the mirror like in the 1130 illuminator for the AO 110
Wow, I have both the 10 and 110 and I thought their condensers were optically compatible. This is new and interesting information for me.

I'm still extremely eager to hear from anyone who has an e600, e800, e1000, or 50i and can let me know the width of the nosepiece dovetail, by the way. Trying to work all this stuff out.
Last edited by farnsy on Mon Jul 26, 2021 7:31 am, edited 1 time in total.

hans
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#11 Post by hans » Mon Jul 26, 2021 2:50 am

farnsy wrote:
Mon Jul 26, 2021 2:08 am
In addition, the very first piece of glass in the illumination train has a significant piece broken off...
Collector lens? Or just some kind of filter? For an LED conversion you probably still want the original collector lens or something similar.
farnsy wrote:
Mon Jul 26, 2021 2:08 am
Wow, I have both the 10 and 110 and I thought their condensers were optically compatible. This is new and interesting information for me.
No idea how much practical effect it has beyond working distance, and I haven't yet tried swapping 10/110 condensers, but would be interesting to try. Actually this reminds me I did find an old Zeiss patent I was going to post that specifically says the aplanatic/achromatic corrections apply to the image of the field iris.

Phill Brown
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#12 Post by Phill Brown » Mon Jul 26, 2021 4:58 am

Image
Labophot 2 is similar set up, metal parts.
I will go with incompatible.
Single lens only.
Design date not so far apart.
6v 30w G4 lamp.
2 diffuser lenses in a removable cassette instead of fixed.
Iris housing mounting different.
alignment of the mirror is critical.
Alignment could be checked with the LED on most mobile phones,can be focused on the lens at the rear to confirm.
Good luck.
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farnsy
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#13 Post by farnsy » Tue Jul 27, 2021 11:36 pm

Thanks a lot for your help. I went ahead and picked up an e600 body. Between the two not-so-complete scopes I have all the parts I need and they are sure to be compatible.

Well, actually I still need a light source. For now I'm going to see how well a dimmable flashlight (maglight style) will work. Later I will rig a properly spec'ed LED system.

Phill Brown
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Re: What microscopes have the same illuminator lens as the Nikon e400?

#14 Post by Phill Brown » Wed Jul 28, 2021 9:44 am

If you have a power supply PCB it will have a part number on.
Electronics are usually easy enough to repair, someone out there can fix it.
Nikon power supplies seem to be their weak point.

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