Nikon FL illuminator

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Saul
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Nikon FL illuminator

Post by Saul »

What purpose serves these two lenses ?

Image

Thanks,
Saul
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JH
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Post by JH »

When you add the extra 50mm the distance increase from the neccesary 160mm to 210mm the lenses handles this so you can use your 160mm objectives.
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Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

JohnyM
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Post by JohnyM »

1,25x tube lenght compensation.

Pau
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Post by Pau »

Jörgen is right.

The lower one (negative telan lens) is divergent, creating an infinite corrected space, the upper one is convergent (tube lens or positive telan lens) restoring the right tube length. Flat optical elements like fluorescence filters do not induce spherical aberration when placed inside the infinite space.

The modern infinite corrected microscopes don't need the lower one and have the tube lens integrated at the microscope head.
Pau

Saul
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Post by Saul »

Jörgen , John & Pau, thank you very much !

My very initial idea :

Image

Image

If I'll maintain right distances (using with/without head & different adapters) with Mitutoyo & other objectives, should I remove them ?

How much they are affecting image quality ?

I can move Mitu up, if needed, closer to the illuminator, just to keep right distance between objective & tube lens (Sigma LSA) - http://www.photomacrography.net/forum/v ... 692#190692
Saul
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Pau
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Post by Pau »

Being the Mitu infinite corrected you don't need the negative telan lens and two tube lenses stacked also seems inadequate, so, yes in principle you should remove the lenses or profit the upper one removing the Sigma LSA

Your binocular head, is for finite or infinite microscopes? (if infinite it will have another tube lens at its lower part!)

In my Zeiss I've tested the (optically similar) fluorescence illuminator with infinite corrected objectives and they work well removing the lower lens, although magnification is lower as the tube lens is shorter than the official Nikon and Olympus ones.
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Saul
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Post by Saul »

Pau wrote:Being the Mitu infinite corrected you don't need the negative telan lens and two tube lenses stacked also seems inadequate, so, yes in principle you should remove the lenses or profit the upper one removing the Sigma LSA

Your binocular head, is for finite or infinite microscopes? (if infinite it will have another tube lens at its lower part!)

In my Zeiss I've tested the (optically similar) fluorescence illuminator with infinite corrected objectives and they work well removing the lower lens, although magnification is lower as the tube lens is shorter than the official Nikon and Olympus ones.
Thanks Pau !

Head was infinite (Reichert), now it is finite :)
http://www.photomacrography.net/forum/v ... 796#232796
http://www.photomacrography.net/forum/v ... 348#191348

Looks like I have to remove them ....
Saul
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Post by Pau »

Head was infinite (Reichert), now it is finite
If you refer to the hammered lens formerly at the photoport it isn't the tube lens
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Saul
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Post by Saul »

Pau wrote:
Head was infinite (Reichert), now it is finite
If you refer to the hammered lens formerly at the photoport it isn't the tube lens
:D , not this one
http://www.photomacrography.net/forum/v ... 233#202233

I have one more same Reichert tube lens, now Robert O'Toole is testing it, in my simple comparison tests it performed pretty good.
Last edited by Saul on Wed Jun 27, 2018 7:27 am, edited 1 time in total.
Saul
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Saul
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Post by Saul »

I'm going to use UV LED - how important is distance between LED and dichroic mirror ?
Light should be collimated ? Diffused ?
As you can see from the photos, my illuminator is missing light source, so I have design something. Most probably it will be Pau's type sliding heat sink
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Pau
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Post by Pau »

Saul wrote:I'm going to use UV LED - how important is distance between LED and dichroic mirror ?
Light should be collimated ? Diffused ?
As you can see from the photos, my illuminator is missing light source,
The FL illuminator is an epi condenser with optics to focus the light source following the Köhler principle.
The light of the light source is not diffused but collimated. In some models (like my Zeiss) there are optics at the lamp housing while in others all optics are at the illuminator (maybe your Nikon?). It is very important to put the LED well centered and at the right distance, so focusing and centering mechanisms are desirable.

Also be aware that many LEDs have built in lenses of different angles and this can affect their focus and coverage, in principle a lensless single chip LED will match better the optics designed for the arc of the HBO lamp. (that said all my LEDs have lenses, and I only have issues with one of them)

Because you already have a white LED used for transillumination a good approach is to test it with the blue excitation filter cube to see the position and how it works
Saul wrote:...so I have design something. Most probably it will be Pau's type sliding heat sink
with your skills I'm sure that you can make something better! :D

What objectives magnification do you plan to use?
For low power I've found that external illumination is more effective that epi having LWD objectives.
A pair of Nichia Convoy S2 do really well
http://www.photomacrography.net/forum/v ... 217#204217
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JohnyM
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Post by JohnyM »

Nikon lamphouses do have optics that work in conjunction with epi-illuminators. There are two types: for fluorescence (hbo/xbo arc) and for VIS (halogen). They are same constructions optically, but FL one is made of quartz and transmits UV, where EPI one is made of ordinary glass, that still transmits UV, but with cut-on 365nm.

That being said, i expect you'll get good results with LED alone as lamphouse optic is variably enlarging light source, and all diodes i know come with spreading "optics" and you can fill the aperture just by getting proper distance from epi-illuminator. Which should be very close.

With your setup, you basically have 3 tube lenses - one in EPI illuminator, one is sigma LSA, one in binocular head. Also one telan lens. You should get rid of all of them and keep just one. LSA is probably best bet, but i dont know how much infinity space it have.

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Post by Saul »

Pau wrote:Because you already have a white LED used for transillumination a good approach is to test it with the blue excitation filter cube to see the position and how it works
Agree, good starting point.
Pau wrote:What objectives magnification do you plan to use?
For low power I've found that external illumination is more effective that epi having LWD objectives.
Would like to use/try all options
JohnyM wrote:...all diodes i know come with spreading "optics" and you can fill the aperture just by getting proper distance from epi-illuminator....
Very good, it means I have to use collimating lens for the "flat" LED only
JohnyM wrote:With your setup, you basically have 3 tube lenses - one in EPI illuminator, one is sigma LSA, one in binocular head. Also one telan lens. You should get rid of all of them and keep just one.
Great, that my initial thought was

3W LEDs will be OK, or I should look for more powerful ones , like 10w?
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JohnyM
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Post by JohnyM »

Nothing is powerfull enough for fluorescence :)
Those 10W diodes are just many weak diodes on single board. You need to find strongest SINGLE diode, otherwise you'll get very uneven illumination or you'll need to use diffusion which ultimatelly bring their power down to that 3W equivalent...

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Post by Pau »

JohnyM wrote:...all diodes i know come with spreading "optics" and you can fill the aperture just by getting proper distance from epi-illuminator....
Very good, it means I have to use collimating lens for the "flat" LED only
I don't think so, the collimating optics at my lamp housing is very strong although the ones inside the Nikon illuminator could be different (mine has only one other lens inside the illuminator). The optics need to be able to focus the LED die at the rear focal plane (and fulfilling it) of the objective after Köhler
There are for sure LEDs without lens, like this one: https://www.lumitronix.com/en_gb/nichia ... 14352.html (I have the NVSU233A-D1 that has a lens and it's the one that have focusing issues in my system)
3W LEDs will be OK, or I should look for more powerful ones , like 10w?
You can put some more money, I have a "3 W" no brand chinese UV LED and, despite working it's not well powered and produces a large amount of white light.
The Nichia I linked is excellent although expensive and I'm also very satisfied with the LG 3535 385nm

Someone did recommend me the LedEngin LZ1-10UV00-0000, but I have not experience with it.
COB LEDs like the 10W you linked are inadequate for microscope illumination at least with the original optics designed for the small arc lamp source.
Pau

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