Search found 2985 matches

by PeteM
Thu Mar 28, 2024 10:04 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

A dry (air-gapped) condenser will strictly limit the effective NA of any subsequent objective to a theoretical maximum of 1 (meaning somewhat less than 1 in practical terms). . . . As Hans noted above, it's likely a bit more complicated. The formula here (Thorlabs site) suggests an additive effect,...
by PeteM
Thu Mar 28, 2024 9:28 pm
Forum: My microscope
Topic: Euromex Microscopes?
Replies: 3
Views: 75

Re: Euromex Microscopes?

. . . I collect microscopes and love to compare and contrast the various models both new and vintage from around the world :-) Thanks, Gary They're serviceable microscopes, but I wouldn't consider most of their models collectible—unless you were interested in the financial acquisition history of L ...
by PeteM
Thu Mar 28, 2024 4:17 pm
Forum: Beginner's corner
Topic: Leica DMLB Condenser
Replies: 9
Views: 488

Re: Leica DMLB Condenser

The slider coming in at an angle just under the DMLB lettering is for a DIC prism. The one for the analyzer is at about the same height, on the left side (facing the microscope).
by PeteM
Wed Mar 27, 2024 9:47 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

Given that you're shooting at higher magnifications, you're probably OK. I was imagining all those extra and fat pixels. But as you say; the extra or larger pixels from one of the newer mirrorless cameras won't help much at 400X and above. I have heard of vibration complaints from some Canon EOS use...
by PeteM
Tue Mar 26, 2024 9:47 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

Harry, The 60x Plan Apo oil 1.40 objective is wonderful for thin, often stained, and stationary specimens. While lower magnification than the 100x Plan Apo oil, it has the same theoretical resolution and (if memory serves) can peer a tiny fraction (something like .02mm is typical) further below a co...
by PeteM
Tue Mar 26, 2024 9:22 pm
Forum: Beginner's corner
Topic: Leica DMLB Condenser
Replies: 9
Views: 488

Re: Leica DMLB Condenser

For polarization, I suggest buying a decent-quality (so it goes to near full extinction) linear camera polarizer with a diameter that matches your field lens. It doesn't have to fit in or on the condenser. Should be under $20 or so on eBay. You'll also need a polarization slider to fit from the side...
by PeteM
Tue Mar 26, 2024 4:14 am
Forum: For forum members who want to buy and sell equipment
Topic: For trade: microscope (DIC etc.) scopes & optics
Replies: 39
Views: 23404

Re: For trade: microscope (DIC etc.) scopes & optics

The first post has been updated once again. I'm now hoping to find - for trade or sale:

- UCL phase contrast condenser for Leica DMLS/DMLB
- Leica 2S1 (Ph2) phase ring
- Nikon 50/55i stage
- Nikon Eclipse PA20 DIC prism
by PeteM
Mon Mar 25, 2024 7:27 pm
Forum: Microscopes and optics
Topic: Substituting LED bulb for incandescent bulb
Replies: 7
Views: 330

Re: Substituting LED bulb for incandescent bulb

I've used the LED Edison-base tiny bulb replacements in a few scopes that needed them. The pluses are low cost, less heat, and longer life. However, while adequate, they don't seem much brighter. You do get the higher color temperature.
by PeteM
Mon Mar 25, 2024 2:26 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

Thanks, Phil.
by PeteM
Mon Mar 25, 2024 12:17 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

Phil, did you basically use a stop at the backside of the Bestscope water immersion objective for darkfield - maybe cut it down to around .90 na?
by PeteM
Sun Mar 24, 2024 11:18 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

FWIW, I do like my 60x oil version with the 1.40 na and a dry condenser - but that is usually with tissue samples, not protists under a cover slip.
by PeteM
Sun Mar 24, 2024 7:06 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

apochronaut wrote:
Sun Mar 24, 2024 5:57 pm
I could have sold you one cheaper and had it there in 10 days, Pete.
Dang. Should have asked if you had spares.
by PeteM
Sun Mar 24, 2024 7:04 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

Harry, Can you share your experience with the 50x Plan oil 0.90 an objective? The minus, for protists under a cover slip, is the oil immersion atop the cover slip. Perhaps there's a simple way to fix the slip in place. The pluses are likely the .30 or so working distance, a decent DIC prism match, t...
by PeteM
Sun Mar 24, 2024 4:41 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 40
Views: 1267

Re: Do I need another objective?

I can share a bit of personal experience with Nikon DIC prisms and the 60x Pl Fluor dry objective. This is the 0.85 n.a. version with 0.30 working distance and a .11 to .23 correction collar. Both the PF60A and PA/PF100 prisms yield a banded background on my first-generation (E600, since ported to a...
by PeteM
Sun Mar 24, 2024 12:03 am
Forum: Microscopes and optics
Topic: Oxidation on front assembly / retraction stopper
Replies: 7
Views: 376

Re: Oxidation on front assembly / retraction stopper

Oxidized metal (rust, tarnish, etc.) won't clean up with typical solvents. And, as noted above, the most volatile ones can affect cements and coatings. Since your glass is good and the damage is cosmetic, you might best consider it a sign of revered older age. If it really bugs you (and occasionally...
by PeteM
Fri Mar 22, 2024 3:55 pm
Forum: Microscopy accessories
Topic: Anti-Static for lenses.
Replies: 26
Views: 1375

Re: Anti-Static for lenses.

Wow I had no idea! I just need to find someone with a Geiger counter now... Here's a result from a quick Google search: https://orau.org/health-physics-museum/collection/consumer/miscellaneous/static-eliminators.html Apparently, polonium-210 has a half-life of 138 days. If your brush is as old as t...
by PeteM
Thu Mar 21, 2024 5:22 pm
Forum: Microscopy accessories
Topic: Anti-Static for lenses.
Replies: 26
Views: 1375

Re: Anti-Static for lenses.

I believe the old photo/film anti-static brushes had a "lightly" radioactive element incorporated with the hairs to produce ions. Not sure if they're still available today.

All the hip kids today use muons . . .
by PeteM
Thu Mar 21, 2024 4:23 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34597

Re: Leica Reichert Jung Polyvar (models)

Thanks for all that additional information, Wayne.
by PeteM
Thu Mar 21, 2024 1:54 am
Forum: Beginner's corner
Topic: Leica DMLB Condenser
Replies: 9
Views: 488

Re: Leica DMLB Condenser

There are typically two or three knurled screws holding the condenser in place. You'll want to rack the stage up and the condenser down to get clear space. I'm pretty sure your model has a small one on the right side that fastens it to a carrier. (#5, Figure 5, on your diagram) Unscrew that. Then un...
by PeteM
Wed Mar 20, 2024 7:32 pm
Forum: Beginner's corner
Topic: Leica DMLB Condenser
Replies: 9
Views: 488

Re: Leica DMLB Condenser

Assuming I guessed right that the top lens slides in and out of position, you should have wide field coverage for your 2.5x objective with it out and excellent images at higher magnification with it in. You probably want to switch it "in" once you're at 10x and maybe even at 4x or 5x. There should b...
by PeteM
Wed Mar 20, 2024 3:46 pm
Forum: Beginner's corner
Topic: Leica DMLB Condenser
Replies: 9
Views: 488

Re: Leica DMLB Condenser

Nebulous, I'm only seeing the first image. It's new to me but looks to be a step up from the standard condenser by having a slide-in and slide-out top lens to accommodate low-power (e.g. 2-2.5x) objectives. Could be wrong - you can easily see if it slides in and out. The standard condenser has a slo...
by PeteM
Wed Mar 20, 2024 3:33 pm
Forum: Microscopy accessories
Topic: Motorized Rotating Display Stand
Replies: 16
Views: 688

Re: Motorized Rotating Display Stand

A classic ringing table will typically have a good bearing, a platen (table) heavy enough to have some inertia, a secure way of centering and holding the slide, and some sort of built-in bridge to steady the pen (brush, etc.). Having a motor to turn it seems the last of the requirements, since almos...
by PeteM
Mon Mar 18, 2024 7:37 pm
Forum: Miscellaneous
Topic: The Place of Value in a World of Fact
Replies: 3
Views: 347

Re: The Place of Value in a World of Fact

There's a huge literature on consciousness - which is somewhere between a twin to a kissing cousin to awareness. Julian Jaynes thought we didn't become conscious until 3000 years ago (Origin of Consciousness in the Breakdown of the Bicameral Mind). However, more recent research with primates shows t...
by PeteM
Sat Mar 16, 2024 4:53 am
Forum: Beginner's corner
Topic: unmarked long silver objective lens?
Replies: 1
Views: 238

Re: unmarked long silver objective lens?

The objective is missing its outer shroud, which would have had the markings. Just guessing from the Nikon turret and the size of the visible lens, I'd guess that it's a Nikon finite objective around (+/-) 10x. It will work without the shroud and it should be possible to figure the magnification eit...
by PeteM
Fri Mar 15, 2024 3:06 am
Forum: Microscopes and optics
Topic: Reichert U.S.A. and Leica. Why the undercorrection?
Replies: 10
Views: 677

Re: Reichert U.S.A. and Leica. Why the undercorrection?

"I would be interested to know if anyone has used a Reichert Austria objective in a Delta based stand" Here's a quick test using a Delta-era Leica 501055 head with L Plan 10x/20 eyepieces. The stand is a DMLS that just came in. It has a yellow hot spot in the illumination—maybe the wrong bulb or ill...
by PeteM
Thu Mar 14, 2024 7:22 pm
Forum: Microscopes and optics
Topic: Reichert U.S.A. and Leica. Why the undercorrection?
Replies: 10
Views: 677

Re: Reichert U.S.A. and Leica. Why the undercorrection?

Here's a shot at summarizing the discussion of eyepiece corrections in a table. There are surely omissions and likely errors. Let me know and I'll update it.

.
AO, Reichert, Leica eyepiece corrections.png
AO, Reichert, Leica eyepiece corrections.png (259.07 KiB) Viewed 408 times
by PeteM
Thu Mar 14, 2024 4:02 am
Forum: Beginner's corner
Topic: What happened to the Leica DMLB?
Replies: 8
Views: 501

Re: What happened to the Leica DMLB?

As you say, US trade policy certainly played a role in the decline of some US companies—as did the internecine battles Wayne covers and a switch from engineers running these companies to financial folks looking for a quick buck as they bought up companies, mashed them together, slashed resources, an...
by PeteM
Wed Mar 13, 2024 10:24 pm
Forum: Beginner's corner
Topic: What happened to the Leica DMLB?
Replies: 8
Views: 501

Re: What happened to the Leica DMLB?

Sad to say, support for legacy products is poor to abysmal in the microscope world. Vendors want you to buy new, rather than bring older ones back to life. In fact, some have threatened to sue for copyright infringement when hobbyists post older manuals with still-active copyrights. Under recent law...
by PeteM
Wed Mar 13, 2024 5:50 am
Forum: Microscopes and optics
Topic: Reichert U.S.A. and Leica. Why the undercorrection?
Replies: 10
Views: 677

Re: Reichert U.S.A. and Leica. Why the undercorrection?

I was thinking it more a matter of production costs - that they might be able to use some existing designs, machines, or processes. It's purely conjecture. Someone intimately involved would know better if any IP, factory preferences, production processes, or machinery carried over. Don't know Leica'...
by PeteM
Wed Mar 13, 2024 4:13 am
Forum: Microscopes and optics
Topic: Reichert U.S.A. and Leica. Why the undercorrection?
Replies: 10
Views: 677

Re: Reichert U.S.A. and Leica. Why the undercorrection?

I've never seen an explanation of this, but I can offer a hypothesis. The buyout occurred at an early time of financiers buying up companies and trying to assemble mini-conglomerates. That sort of management would very likely have wanted to invest as little as possible in R&D. Thus, bringing forward...