Search found 402 matches

by viktor j nilsson
Mon Apr 12, 2021 10:27 pm
Forum: Illumination Techniques
Topic: can Phase contrast kit work WITHOUT Köhler ???
Replies: 17
Views: 541

Re: can Phase contrast kit work WITHOUT Köhler ???

BM = bright medium, aka negative phase contrast.
by viktor j nilsson
Mon Apr 12, 2021 5:53 pm
Forum: Beginner's corner
Topic: Decision: Amscope T400A-30W Any thoughts?
Replies: 21
Views: 372

Re: Decision: Amscope T400A-30W Any thoughts?

Are Amscope microscopes ever NOT on sale? I sure have never seen them being sold at the "list price". Here in Sweden, that type of false marketing is illegal. But clearly not in the US. Is the current "sale" price really any lower than usual? I don't keep tabs.
by viktor j nilsson
Mon Apr 12, 2021 6:31 am
Forum: Beginner's corner
Topic: Very dirty Nikon microscope, what to do?
Replies: 10
Views: 308

Re: Very dirty Nikon microscope, what to do?

Fixing up a Nikon S is definitely something you can do yourself if you have some basic mechanical experience (and it seems you do). Fixing your own microscope is a great way to learn about and become familiar with your equipment. With that said, I wonder if it's worth it. It sounds as if your micros...
by viktor j nilsson
Fri Apr 02, 2021 2:36 pm
Forum: About the website, the magazine and this forum
Topic: Make the Forum HTTPS Secure
Replies: 3
Views: 1140

Re: Make the Forum HTTPS Secure

Michael, pretty sure that's a spam bot

Edit: Oh, sorry, just noticed you replied to the original poster. Nevermind.
by viktor j nilsson
Wed Mar 31, 2021 7:39 pm
Forum: Introduce yourself
Topic: Hi , I'm Chris (from Paris)
Replies: 7
Views: 360

Re: Hi , I'm Chris (from Paris)

Welcome to this great forum, Chris! Good to see you here - I'm the Swedish guy that sold you the phase objective that's now on its way to you. I hope you enjoy it. It's a lot of fun to tinker with different illumination techniques, and the folks on this forum are always happy to help. Do keep us upd...
by viktor j nilsson
Tue Mar 30, 2021 10:50 am
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

It is true, actually. Old draw-tube microscopes worked on this principle - by increasing or decreasing the tube length, the user could -- to some extent -- compensate for differences in the coverglass medium thickness/RI and reduce spherical aberration. I believe that it introduced other aberrations...
by viktor j nilsson
Mon Mar 29, 2021 11:43 am
Forum: Pictures and Videos
Topic: Salt water embryo.
Replies: 8
Views: 290

Re: Salt water embryo.

Hey! I do have a Heine, but I've never used it with Leitz Pv objectives. Only Nikon Phase objectives (that have a MUCH thicker phase rings than the light cone produced by the Heine) and as a darkfield condenser. I would have thought that it would perform beautifully with the right objectives, so I a...
by viktor j nilsson
Sat Mar 27, 2021 2:49 pm
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

Ah, I think I'm beginning to understand what you're getting at. If I'm correct, you're saying that it's not enough that all three eyepieces are parfocal, but they have to be parfocal at exactly 160mm? I didn't think the tube length was that critical - I thought it only influenced magnification? So ...
by viktor j nilsson
Sat Mar 27, 2021 1:20 pm
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

Oh, but if you are using the same eyepieces for viewing and photographing, then it's very possible that you're picking up the image at a different focal plane than where it should be. Do you have any "real" eyepieces to compare with? They don't need to be optically matched to the Nikon objectives, a...
by viktor j nilsson
Sat Mar 27, 2021 10:49 am
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

If your regular eyepieces are seated exactly where they are supposed to be, and your photo eyepiece and camera setup is parfocal with the viewing eyepieces, then you are very close to the correct tube length. Tolerance to tube length deviations is highly dependent on NA. At low NA, you can change th...
by viktor j nilsson
Sat Mar 27, 2021 10:30 am
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

One other thing that's really critical with a dry NA 0.85 objective is to get the tube length exactly right. You're not using this with your astronomical eyepiece, are you? Did you manage to get that to be perfectly parfocal with your viewing eyepieces? If your photo eyepiece is off even by 2mm, ima...
by viktor j nilsson
Fri Mar 26, 2021 6:54 pm
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

LouiseScot wrote: Thanks for the advice and the pointers! I'll have a go tomorrow. I'll probably find it easier with the Mediterranean diatom slide I have :)

Louise
Good luck!
And yes, even with the collar I think it's better to judge its performance on a modern slide with a cover slip that's close to 0.17
by viktor j nilsson
Fri Mar 26, 2021 6:34 pm
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

Clear advantage for the Fluor. However, it does looks a little hazy, which looks a lot like spherical aberration to me. How carefully did you optimize the correction collar setting? At 0.85 it needs to be set quite precisely to minimize spherical aberrations. It's a very nice objective, and pretty ...
by viktor j nilsson
Fri Mar 26, 2021 4:56 pm
Forum: Microscopes and optics
Topic: Swift Achromat vs Nikon Fluor
Replies: 47
Views: 1132

Re: Swift Achromat vs Nikon Fluor

Clear advantage for the Fluor. However, it does looks a little hazy, which looks a lot like spherical aberration to me. How carefully did you optimize the correction collar setting? At 0.85 it needs to be set quite precisely to minimize spherical aberrations. It's a very nice objective, and pretty e...
by viktor j nilsson
Thu Mar 25, 2021 1:24 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water/Glycerine immersion instead of oil immersion for darkfield

Very, very nice addition with the glycerol comparison. This thread will serve as a definitive reference on this topic! I've always thought of glycerine as more user friendly than oil, but the two of you have made some very good arguments that have caused me to reconsider. Nevertheless, your images s...
by viktor j nilsson
Thu Mar 25, 2021 7:56 am
Forum: For forum members who want to buy and sell equipment
Topic: WTB: Olympus BH-2 BH2-CA, 1.25x intermediate or simillar
Replies: 8
Views: 349

Re: WTB: Olympus BH-2 BH2-CA, 1.25x intermediate or simillar

Maybe this could work for you then? https://www.ebay.com/itm/143701143746 I do think, however, that a teleconverter would be a better solution for you. Thanks, I have been following that one for a while hoping price would go a bit lower, he has 4 of them. I may send an offer The problem with the TC...
by viktor j nilsson
Thu Mar 25, 2021 12:08 am
Forum: For forum members who want to buy and sell equipment
Topic: WTB: Olympus BH-2 BH2-CA, 1.25x intermediate or simillar
Replies: 8
Views: 349

Re: WTB: Olympus BH-2 BH2-CA, 1.25x intermediate or simillar

Maybe this could work for you then?
https://www.ebay.com/itm/143701143746

I do think, however, that a teleconverter would be a better solution for you.
by viktor j nilsson
Wed Mar 24, 2021 11:17 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

...glycerol... I hope you do not even think of doing that stupid heating of glycerol in a home oven. The cited reliable article says "in a sand bath, in the hood" and tells you to monitor the temperature of the liquid. Glycerol might decompose or even catch fire in a closed poorly-controlled oven. ...
by viktor j nilsson
Wed Mar 24, 2021 10:38 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

Agree, 11) looks perfect. Now that we know what it is capable of - would you be interested in doing that one with glycerol instead? I would love to see that. My glycerol is old so it contains some water, I will give it a try though and in addition, try and find drier glycerol. Pure glycerol is MUCH...
by viktor j nilsson
Wed Mar 24, 2021 8:27 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

hans wrote: If the lines are transparent openings in the metallization then the dark center would be expected with darkfield illumination since only light reflected/diffracted from the edges of the openings would make it into the objective?
Ah, yes that's a reasonable interpretation.
by viktor j nilsson
Wed Mar 24, 2021 8:24 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

Agree, 11) looks perfect.

Now that we know what it is capable of - would you be interested in doing that one with glycerol instead? I would love to see that.
by viktor j nilsson
Wed Mar 24, 2021 2:58 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

Wait, are the white lines supposed to have a dark center? Then why are the lines all white in #8 and #9. Now I am even more confused! Are the lines scribed into a dark-colored glass? Or are they cut straight through? The stage micrometer is made of a glass disk that forms an opaque background, and ...
by viktor j nilsson
Wed Mar 24, 2021 1:08 pm
Forum: Microscopes and optics
Topic: Neutral eyepieces for projection or afocal method with nikon CFNs? Test added
Replies: 10
Views: 416

Re: Neutral eyepieces for projection or afocal method with nikon CFNs? Test added

The Nikon SC has some kind of corrective lens after the objectives (pre infinity era prototype?? :mrgreen: ), so I figured out the eyepiece would be quite neutral https://live.staticflickr.com/65535/50939278982_4997568742_w.jpg If I remember correctly, this lens is basically a common rear element f...
by viktor j nilsson
Wed Mar 24, 2021 12:49 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

Wait, are the white lines supposed to have a dark center? Then why are the lines all white in #8 and #9. Now I am even more confused!

Are the lines scribed into a dark-colored glass? Or are they cut straight through?
by viktor j nilsson
Wed Mar 24, 2021 12:23 pm
Forum: Illumination Techniques
Topic: Water/Glycerine immersion instead of oil immersion for darkfield
Replies: 33
Views: 972

Re: Water immersion instead of oil immersion for darkfield

Well, that number 8) is a cracking combination! A little puzzled by some of them. - If your 40x 0.75 is designed to be used with a coverslip, then why is the image with coverslip (7) so much worse than the one without (6)? - Very surprising that the water immersed 40x 0.8 perform worse with the turr...
by viktor j nilsson
Wed Mar 24, 2021 10:20 am
Forum: Microscopes and optics
Topic: Neutral eyepieces for projection or afocal method with nikon CFNs? Test added
Replies: 10
Views: 416

Re: Neutral eyepieces for projection or afocal method with nikon CFNs? Test added

When you say that you use the Nikon SC eyepiece as a Photo eyepiece, do you mean that you raise it up? How much? Pretty good results with that eyepiece. A bit surprising since the SC system is a basic student-grade microscope that's not really meant to be compatible with anything else. Cool result! ...
by viktor j nilsson
Sat Mar 20, 2021 7:05 pm
Forum: Microscopes and optics
Topic: Wild M5a stereo microscope pros and cons?
Replies: 6
Views: 338

Re: Wild M5a stereo microscope pros and cons?

I use a M5 at home, and I've used a lot of different Wild/Leica scopes at work, the ones I've used the most are the M5A, M3C, M3Z, M8 and Leica MZ9.5. I have heard the the widely spaced tubes gives a stronger sense of perspective. I can't say that it is something I have felt strongly. If the effect ...
by viktor j nilsson
Fri Mar 19, 2021 8:22 am
Forum: Beginner's corner
Topic: Condensers, how do you properly use them?
Replies: 17
Views: 772

Re: Condensers, how do you properly use them?

I use water instead of oil on the condenser for high NA objectives, its a decent compromise (according to my math it allows a cone of light with NA=1.2) ... Is that number less than 1.33 because it is based on some criteria like 50% transmission rather than critical angle? Glycerol would probably w...
by viktor j nilsson
Thu Mar 18, 2021 2:09 pm
Forum: Specimens, samples and slides
Topic: How to clean coverslips?
Replies: 17
Views: 511

Re: How to clean coverslips?

Darkfield is extremely demanding, it brings out all the little dust specks. Very few, if any, boxes of cover glass seem to come clean enough out of the box for high NA darkfield. This was a pretty interesting discussion on different ways of getting them as clean as possible: https://www.microbehunte...
by viktor j nilsson
Tue Mar 16, 2021 8:45 pm
Forum: Microscopes and optics
Topic: Mosquito wing for objective testing
Replies: 18
Views: 619

Re: Mosquito wing for objective testing

So you can put the dic and pol sliders in either of them? Cool, that suggests that the housings are indeed identical. Intermediate tubes need to have two lenses. In a finite system, the objective projects a converging bundle of light that comes to focus at the intermediate image plane located 10mm b...