Search found 112 matches

by david_b
Fri Jul 10, 2020 8:45 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

Kirby, thank you for posting this. If it were the case that setting Kohler illumination is fully automated then that would indeed be a convenience. But...would you/your friend agree that without a field diaphragm, the flare and contrast cannot be optimised for each objective, according to the Kohler...
by david_b
Thu Jul 09, 2020 7:40 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

Zuul wrote:
Thu Jul 09, 2020 7:28 pm
Perhaps “NeoKöhler” would be better? :D
NoKohler ?
by david_b
Thu Jul 09, 2020 6:10 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

I meant adopting the term 'fixed Kohler', not referring to the technology.
by david_b
Thu Jul 09, 2020 4:46 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

75RR wrote:
Thu Jul 09, 2020 3:52 pm
A field diaphragm is one of the essential parts of what they are now calling Full Köhler, I think Fixed Köhler is perilously close to being a kissing cousin to 2000x magnification.
That's what I'm thinking, but if so, I'm surprised to see Olympus adopting it.
by david_b
Thu Jul 09, 2020 4:41 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

As above, the field diaphragm is set to be just outside the field of view for whatever objective is in use, not normally wide open.
The principle is the same as the lens hoods, 'barn doors', bits of polystyrene etc. that pre-smartphone photographers used to reduce flare and maintain contrast.
by david_b
Thu Jul 09, 2020 3:38 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köhler

I understand that the lamp is pre-centered, but my understanding of Kohler is that a field diaphragm is essential to match the spread of illumination to the objective in use... https://www.olympus-lifescience.com/en/microscope-resource/primer/anatomy/kohler/ If a field diaphragm is an essential part...
by david_b
Wed Jul 08, 2020 5:55 pm
Forum: Microscopes and optics
Topic: Euromex or Motic?
Replies: 54
Views: 464

Re: Euromex or Motic?

Hi David I thought I'd replied to this earlier but maybe I didn't 'submit', d'uh. Anyway, I'd asked you what Motic objectives you have/had? Are they 'EC' Plan achromats? They do 10x/22mm UC eyepieces and UC Plan objectives (optional Phase) for the Panthera. I asked Motic what the difference is. The...
by david_b
Wed Jul 08, 2020 6:18 am
Forum: Microscopes and optics
Topic: Euromex or Motic?
Replies: 54
Views: 464

Re: Euromex or Motic?

I had a Brunel microscope with plan objectives and decided to upgrade to a Motic BA310 I found that the change to 30mm eyepieces was a huge improvement in viewing comfort, but the Motic ojectives were no better than the generic Brunel objectives and in a direct comparison actually show more chromati...
by david_b
Sun Jul 05, 2020 1:39 pm
Forum: Microscopes and optics
Topic: Olympus objectives
Replies: 3
Views: 116

Re: Olympus objectives

As above - Plan is UIS1 and Plan N is UIS2 - a coating difference I believe. I think the 'CN' designated those fitted to the CX range, the 'just N' for the BX series. I've compared both 'CN' and 'just N' on the same 'scope (BX40 and BX50) and there's absolutely no difference either by eyepiece of c...
by david_b
Sat Jul 04, 2020 8:34 pm
Forum: Microscopes and optics
Topic: Olympus objectives
Replies: 3
Views: 116

Olympus objectives

Other than price, what is the difference between Olympus PlanC N objectives and the Plan N objectives?

https://www.astroshop.eu/for-microscope ... ve/p,49915
https://www.astroshop.eu/for-microscope ... iv/p,49927
by david_b
Sat Jul 04, 2020 8:27 pm
Forum: Pictures and Videos
Topic: Stomoxys with ticks?
Replies: 5
Views: 167

Re: Stomoxys with ticks?

As far as I know, ticks live on the blood of mammals.
by david_b
Sat Jul 04, 2020 11:58 am
Forum: Pictures and Videos
Topic: Stomoxys with ticks?
Replies: 5
Views: 167

Re: Stomoxys with ticks?

They look like mites.
by david_b
Fri Jul 03, 2020 9:27 pm
Forum: Beginner's corner
Topic: The Dirty Cover Glass Blues
Replies: 25
Views: 792

Re: The Dirty Cover Glass Blues

by david_b
Wed Jul 01, 2020 8:40 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köeler

Thanks, David ... it was just a hope The Zeiss document does include an image that clearly shows an array of LEDs ... so I’m pretty sure that we are on the right track. Like you, I can find no definition or explanation of the term ... but it seems to be in fairly widespread use: Olympus, Zeiss, and...
by david_b
Wed Jul 01, 2020 2:31 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köeler

MichaelG. wrote:
Wed Jul 01, 2020 12:59 pm
Do you have any detail pictures of the light source, David ??
I only have the brochure that I linked to and the (very interesting) one in your previous link.

I also searched Olympus lifescience website:
0 results for fixed kohler We are sorry but your search returned no results.
by david_b
Wed Jul 01, 2020 12:41 pm
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Re: Fixed Köeler

It appears to be a ‘convenient approximation’ for routine [non-critical] use, David This, from Zeiss, goes a little further towards explaining: http://focuspi.com/Site/AXIO_SCOPE_A-1_files/AXIO%20SCOPE%20A-1%20BIO60-2-0004_e.pdf] [see pp7-9] MichaelG. Probably, it has no field diaphragm... I'm stil...
by david_b
Wed Jul 01, 2020 7:16 am
Forum: Microscopes and optics
Topic: Fixed Köhler
Replies: 45
Views: 953

Fixed Köhler

I'm looking at the Olympus CX33 and CX43 microscopes and note they have "fixed Köhler" illumination.
I assume this means there is no adjustable field diaphragm?
How does fixed Köhler work, and does it have any disadvantages?

https://www.olympus-lifescience.com/en/ ... t/cx43-33/
by david_b
Thu Jun 25, 2020 5:58 am
Forum: Pictures and Videos
Topic: My First Attempts at Digital Photomicrography
Replies: 44
Views: 892

Re: My First Attempts at Digital Photomicrography

Timemaster1212 wrote:
Thu Jun 25, 2020 3:02 am
So here is some more pictures with some differing settings
I'm only seeing the original photo and the edited version.
What objective was used?
Is this the entire view as seen through the eyepiece, or has it been cropped?
by david_b
Wed Jun 24, 2020 6:51 pm
Forum: Pictures and Videos
Topic: My First Attempts at Digital Photomicrography
Replies: 44
Views: 892

Re: My First Attempts at Digital Photomicrography

As others have said, the photos are underexposed.
What is preventing you from setting the correct exopsure in Canon Utilities?
by david_b
Wed Jun 24, 2020 3:31 pm
Forum: Pictures and Videos
Topic: My First Attempts at Digital Photomicrography
Replies: 44
Views: 892

Re: My First Attempts at Digital Photomicrography

You say that the microscope is set up for phase contrast. Are these all phase images?
In the photo of your setup it looks as though the condenser is set to brightfield?
by david_b
Mon Jun 01, 2020 7:55 pm
Forum: Identification help
Topic: What tree is this leave from?
Replies: 8
Views: 288

Re: What tree is this leave from?

Could be silver birch, could be lime. More info needed.
by david_b
Wed May 13, 2020 6:59 pm
Forum: Beginner's corner
Topic: Imaging help using a Canon dslr
Replies: 20
Views: 1101

Re: Imaging help using a Canon dslr

For that you would need a relay lens. Good point, thanks for that. So the next question is : Is there any advantage (or reason) to want to put a dslr on the trino port considering the optical complications - no provision for a relay lens in the Swift tube ? Is the quality of the usb eyepiece camera...
by david_b
Mon May 11, 2020 7:04 pm
Forum: Beginner's corner
Topic: Imaging help using a Canon dslr
Replies: 20
Views: 1101

Re: Imaging help using a Canon dslr

The T2 ring adapter will fit but will not be parfocal with the eyepieces.
For that you would need a relay lens.
The trinocular is most likely a permanent 50/50 split (50% to trinoc.. 50% to eyepieces).
by david_b
Sun May 10, 2020 7:29 pm
Forum: Camera systems and imaging
Topic: Images from LabCam and LabCam Pro
Replies: 2
Views: 423

Re: Images from LabCam and LabCam Pro

Well the LabCam result looks poor, but all of these images are heavily compressed, are you able to post the full size images?
Which iPhone was used?
by david_b
Wed Apr 22, 2020 8:13 pm
Forum: Microscopes and optics
Topic: Olympus BH-2 question
Replies: 8
Views: 692

Re: Olympus BH-2 question

Three other options: 1) Recollection is that the dovetail base of the condenser comes off with a few screws. Can't recall if extra care is required to keep the iris leaves in place as it's removed - replacing those requires a bit of patience. Anyhow once off, the inside can easily be machined, part...
by david_b
Wed Apr 22, 2020 8:05 pm
Forum: Microscopes and optics
Topic: Olympus BH-2 question
Replies: 8
Views: 692

Re: Olympus BH-2 question

David asked me this question through another channel ... Initially I answered, no, nothing will keep insert inside because of the conical shape. Even simplified insert (no magnets, flat base) will not help - condenser base is hanging in the air... But...morning is smarter than evening - I have very...
by david_b
Wed Apr 22, 2020 7:41 pm
Forum: Microscopes and optics
Topic: Olympus BH-2 question
Replies: 8
Views: 692

Re: Olympus BH-2 question

Something like thus?: http://earth2geologists.net/Microscopes/Olympus_images/BHS_substage.jpg Found from http://earth2geologists.net/Microscopes/OlympusScopes.htm Unless I am missing something, that looks to be the easiest solution. If you have access to a 3D printer, something like that could be w...
by david_b
Wed Apr 22, 2020 6:55 am
Forum: Microscopes and optics
Topic: Olympus BH-2 question
Replies: 8
Views: 692

Olympus BH-2 question

I have an Olympus BH-2 BHS with a flip-top condenser. There is no swing out filter holder or slide. How can I attach patch stops for darkfield, oblique illumination etc.? https://i.ibb.co/g7Q4Gvx/IMG-2585.jpg https://i.ibb.co/zFDzw76/IMG-2586.jpg https://i.ibb.co/PN8bRkY/IMG-2587.jpg https://i.ibb.c...