Search found 109 matches

by abednego1995
Thu Jan 28, 2021 2:36 pm
Forum: Microscopes and optics
Topic: A permanent grease for sealed microscope components: Krytox
Replies: 14
Views: 2474

Re: A permanent grease for sealed microscope components: Krytox

Nice addition. Where do you get that fine PTFE powder?

Cheers,
John
by abednego1995
Wed Jan 13, 2021 1:34 am
Forum: Microscopes and optics
Topic: Nikon gene sequencer objectives
Replies: 47
Views: 4068

Re: Nikon gene sequencer objectives

Yeah, I’ve seen your comparisons on the Nikon Users Group on fb. Those oculars are impressive considering their price.
by abednego1995
Tue Jan 12, 2021 9:58 am
Forum: Microscopes and optics
Topic: Nikon gene sequencer objectives
Replies: 47
Views: 4068

Re: Nikon gene sequencer objectives

Hmmmmm. Never thought about that since PSFs are obtained for each channel, shift and rotation corrected in software. That applies even for the best objectives. Would be more than nice to have one "perfect lens" though:-) But I would guess, yes. If the objective were perfect, and the imaging train is...
by abednego1995
Tue Jan 12, 2021 6:08 am
Forum: Microscopes and optics
Topic: Nikon gene sequencer objectives
Replies: 47
Views: 4068

Re: Nikon gene sequencer objectives

Well, that's because it isn't public (or I'm just not aware of a public source.) I asked my Nikon rep at my lab. Another way to guess the "actual" available FN would be to look into what intermediate magnification is required for imaging on the system. This has been long 2.5x (135 format, 46mm diago...
by abednego1995
Mon Jan 11, 2021 10:30 pm
Forum: Microscopes and optics
Topic: Nikon gene sequencer objectives
Replies: 47
Views: 4068

Re: Nikon gene sequencer objectives

First, the tube lens can't deliver. Second, we can't see outside of around FN20mm and the center of the FoV at the same time. The second reason is why they abandoned the UW FN26.5 oculars for the UW FN25.0 oculars.
by abednego1995
Mon Jan 11, 2021 2:33 pm
Forum: Microscopes and optics
Topic: Nikon gene sequencer objectives
Replies: 47
Views: 4068

Re: Nikon gene sequencer objectives

That, is due to Nikon never claiming to have a periphery perfect image in the oculars. They used to have a perfectly corrected CFD ocular for the Biophot around 1978, but didn't sell well due to it's high cost. Going back to the CFI system, Nikon's tube lens is only PSF perfect to FN18.0mm up to the...
by abednego1995
Sat Nov 14, 2020 3:21 am
Forum: Digital processing
Topic: Filtering main light source vs post processing of RGB channels.
Replies: 8
Views: 2648

Re: Filtering main light source vs post processing of RGB channels.

Well, it would depend on how strict you want it to be. If it's just for getting rid of color and spherical aberrations, both would work OK. Post processing would be a bit harder since it's difficult to discern the best focus point in green while looking at an rgb image. Another consideration would b...
by abednego1995
Sun Nov 08, 2020 8:40 am
Forum: Microscopes and optics
Topic: Nikon E400 stage has some wiggle in the y direction, anyone know how to fix?
Replies: 8
Views: 1978

Re: Nikon E400 stage has some wiggle in the y direction, anyone know how to fix?

These stages use cross-roller bearings, and the rails that hold them are pre-tensioned and fastened with screws. A sharp knock can break this tension and give you the slight but annoying wiggle. Just loosen the screws on the guide rail, clamp it firmly, and refasten them. This only will help if the ...
by abednego1995
Sat Oct 24, 2020 11:56 am
Forum: Microscopes and optics
Topic: Cleaning wave plates
Replies: 9
Views: 817

Re: Cleaning wave plates

viktor j nilsson wrote:
Sat Oct 24, 2020 11:49 am
rests on a 'shelf' inside the hole
Exactly. Ever seen stress lines in polarized light? The last thing you would want to subject an element in a pol train is stress. Minimum amount of "soft" adhesive holds them in place.
by abednego1995
Fri Oct 23, 2020 11:05 pm
Forum: Microscopes and optics
Topic: Cleaning wave plates
Replies: 9
Views: 817

Re: Cleaning wave plates

Those wave plates are usually a sandwitch of optical glass and mica, if not quartz. Normal protocol with objectives will work Ok, just be careful not to immerse the edges with solvents that may attack the optical bonding. And dissassembling wave plates are a big nono. You'll never get the axes right...
by abednego1995
Thu Oct 22, 2020 1:47 pm
Forum: Microscopes and optics
Topic: Nikon inverted objective question
Replies: 2
Views: 336

Re: Nikon inverted objective question

Nice find. That objective is for the older MD, MSD scopes. That cap has a flat glass window with a thckness of 1.5mm. For inverted observation through a petri dish, it is removed and correction collar adjusted to whatever thickness the petri dish is. For normal observation on upright microscopes as ...
by abednego1995
Sat Oct 10, 2020 10:42 pm
Forum: Microscopes and optics
Topic: A blast from Nikon's past
Replies: 4
Views: 618

Re: A blast from Nikon's past

Interesting kit, but only simple Epi, Interference Phase Contrast, Epi DIC and parts for the Diascopic fluorescence phase unit included. No transmitted DIC. Agreed 2.5k is overblown.
by abednego1995
Thu Sep 03, 2020 5:05 am
Forum: Microscopy accessories
Topic: New infinity corrected water immersion 100X objectives have arrived..
Replies: 24
Views: 3550

Re: New infinity corrected water immersion 100X objectives soon.

Very interesting, and awesome!
Are the objectives going to be corrected for 0.17mm coverslips or will they be just for dipping??

Cheers,
John
by abednego1995
Thu Aug 27, 2020 1:03 pm
Forum: Microscopes and optics
Topic: Opening up an objective!
Replies: 6
Views: 1026

Re: Opening up an objective!

The horror! The horror!
by abednego1995
Wed Aug 26, 2020 12:00 am
Forum: Microscopes and optics
Topic: Nikon Plan Apo Lambda 20x - ok??
Replies: 39
Views: 3846

Re: Nikon Plan Apo Lambda 20x - ok??

Ah, Ok. I’ve found it anyway. Nikon writes different info on the front and back of the objective. The seller’s photo has it on the second photo. It’s a genuine PA Lambda 20x.

Cheers,
John
by abednego1995
Tue Aug 25, 2020 11:48 pm
Forum: Microscopes and optics
Topic: Nikon Plan Apo Lambda 20x - ok??
Replies: 39
Views: 3846

Re: Nikon Plan Apo Lambda 20x - ok??

BTW, do you have the URL?
Your description of the listing having Lambda etc.. only in the listing and not on the barrel...is somewhat "concerning"
by abednego1995
Tue Aug 25, 2020 11:38 pm
Forum: Microscopes and optics
Topic: Nikon Plan Apo Lambda 20x - ok??
Replies: 39
Views: 3846

Re: Nikon Plan Apo Lambda 20x - ok??

Well, I've seen the Lambda 20x in pathology slide scanners but that's a recent application, and I'd doubt it would come with a case. If there are multiple examples, I would suspect a (large) lab closure, or some kind of government surplus. In that case, the intent for procurement would likely be for...
by abednego1995
Tue Aug 25, 2020 11:04 pm
Forum: Microscopes and optics
Topic: Nikon Plan Apo Lambda 20x - ok??
Replies: 39
Views: 3846

Re: Nikon Plan Apo Lambda 20x - ok??

Good catch, but I'll add in some more info. The CFI60 Plan Apo Lambda 20x wasn't used in gene sequencers as far as I know. The latest machines use discrete optics tailored to each machines specific need (i.e. WD, compensation, wavelength characteristics). The brownish barrelled variants of the CFI60...
by abednego1995
Mon Aug 24, 2020 12:37 pm
Forum: Resources (online, books etc.)
Topic: Nikon Ske or other Nikon?
Replies: 5
Views: 1610

Re: Nikon Ske or other Nikon?

Thanks, that makes it clearer. That's the earliest version of the S-Ke in production from 1963-65. As Pete points out, this particular version with separate knobs for coarse/fine focus doesn't suffer from nylon gear fracture that is endemic with the later models. However, from the photo the scope is...
by abednego1995
Mon Aug 24, 2020 7:35 am
Forum: Pictures and Videos
Topic: Stentor in pol interference contrast
Replies: 8
Views: 1142

Re: Stentor in pol interference contrast

Brilliant movie!
Jamin-Lebedev interference?
by abednego1995
Sun Aug 23, 2020 10:52 pm
Forum: Resources (online, books etc.)
Topic: Nikon Ske or other Nikon?
Replies: 5
Views: 1610

Re: Nikon Ske or other Nikon?

Looks like there's no image?
by abednego1995
Thu Aug 20, 2020 5:25 am
Forum: Microscopes and optics
Topic: Phase Telescope with reticle
Replies: 3
Views: 695

Re: Phase Telescope with reticle

Elaborating on Hans's post, assuming you have a phase telescope that is of Keplarian make, there is a virtual image of the objective back focal plane (BFP) to be observed just below the eyepiece. So if you can add a reticle at that plane, that will enable you to superimpose it on the BFP image. Just...
by abednego1995
Mon Aug 17, 2020 10:23 am
Forum: Camera systems and imaging
Topic: How important is axial exit/entrance pupil positioning in an afocal configuration?
Replies: 14
Views: 2338

Re: How important is axial exit/entrance pupil positioning in an afocal configuration?

Good place to start would be the equations available at Edmund Optics. It's originally for determining the acceptable displacement between an infinite objective and it's tube lens but it also would apply in an afocal setup. https://www.edmundoptics.com/knowledge-center/application-notes/microscopy/u...
by abednego1995
Fri Aug 14, 2020 1:57 pm
Forum: Microscopes and optics
Topic: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30
Replies: 22
Views: 2472

Re: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30

Hmmmm.... how to prove if it uses fluorite...
No idea there, maybe dissasemble it? But destroying an otherwise fine objective is... painful.

Well, if the design calls for fluorite, why doubt it?
by abednego1995
Fri Aug 14, 2020 12:01 am
Forum: Microscopes and optics
Topic: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30
Replies: 22
Views: 2472

Re: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30

Here's the diagram for the PlanApo 100x NA1.30 from a Japanese publication.
The hatched elements are probably fluorite.

Systematic Survey on Optical Microscope Technology in Japan, C.Nagano, 国立科学博物館技術の系統化調査報告 Vol.24 2017. March. p.373
by abednego1995
Thu Aug 13, 2020 11:56 pm
Forum: Microscopes and optics
Topic: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30
Replies: 22
Views: 2472

Re: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30

The parfocal distance is only 33.6mm compared with the 45mm of the CF series objectives intended for your Optiphot. Did they go from 33.6mm to the JIS Standard 36mm and then to DIN 45mm or did they go straight to DIN? Well, I'm not quite sure where that number for the JIS came from since Nikon has ...
by abednego1995
Thu Aug 13, 2020 3:54 pm
Forum: Microscopes and optics
Topic: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30
Replies: 22
Views: 2472

Re: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30

Well, it's a difficult problem there. Not techincally "lying" but it's a matter of where you place the design goals and acceptable tolerances. At the time it came out, it was probably comparable to competitors designs. But over time, it became "unacceptable" and I think it was Leitz (not sure here, ...
by abednego1995
Thu Aug 13, 2020 3:42 pm
Forum: Microscopes and optics
Topic: An interesting patent [for microscope objective]
Replies: 3
Views: 931

Re: An interesting patent [for microscope objective]

That's one expensive lens design...
They're using 2 fluorite elements in the first embodiment, and 3(!) in the second. If they had redesigned it in 1975 (That's when Schott came out with their first ED glass FK01), that would have made an well corrected and affordable LWD objective.
by abednego1995
Thu Aug 13, 2020 2:53 pm
Forum: Microscopes and optics
Topic: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30
Replies: 22
Views: 2472

Re: NIKON OBJETIVO MICROSCOPIO APO 100X PLAN HI 1.30

That's a Plan Apo 100x NA1.30 for the older "black" painted S series microscopes from the 60-70s. The parfocal distance is only 33.6mm compared with the 45mm of the CF series objectives intended for your Optiphot. Hence the trouble mounting it (it's impossible to raise the stage to compensate) Plus,...