🔬 Effect of Condenser and Koehler diaphragms
HTML-код
- Опубликовано: 20 июн 2019
- Condenser and Koehler (Köhler) diaphragms have a different effect on the quality of the image and they are used for different things.
🎈 SUPPORT
Become a Patron: / microbehunter
🔬 MICROSCOPE RECOMMENDATION
I receive many questions on which microscope one should buy. I recommend the following models for amateur microscopy (Affiliate Links to Amazon):
Children’s/Introductory - Swift or National Optical SS110: amzn.to/2WdS4PX
For Amateurs - Swift SW380T (with phototube) or Swift SW380B: amzn.to/3fu7aIY
👜 AMAZON AFFILIATE SHOP
US/World: www.amazon.com/shop/microbehu...
Canada: www.amazon.ca/shop/microbehunter
Germany/Europe: www.amazon.de/shop/microbehunter
UK/Europe: www.amazon.co.uk/shop/microbe...
🎬 RUclips CHANNELS
Microbehunter: / microbehunter
Microscopic Mysteries - Guess the specimen: / @microscopicmysteries
Microbe Talk - Ask a microbiologist! / @allthingsmicrobes
💻 OTHER LINKS
Main Website - Tons of microscopy info: www.microbehunter.com
MicroWorldArchive - www.microworldarchive.org
Forum - Connect to other microscopists: www.microscopy-forum.com
Instagram - Cool pictures I made: / microbehunter
Facebook - Here I post videos: / microbehunter
✔ Check these Hashtags! #microbehunter #science #microscope 
Наука
I was looking for a video on microscope condensers because you mentioned adjusting it in a reply to a question I posted on another one of your videos and here you are again answering our question!
I always learn something new with each of your videos. Thank you!
Wow! I have been especially confused about the value of the field diaphragm. Now, I understand. Also, using the piece of paper to show the light beam pattern was very enlightening!
As usual, great job!
This was very very useful indeed. Thank you for posting.
I love this channel! I am learning so much! Thank you!
Thanks for the useful info!
close the condensor-iris, center the iris, make condensor as high as possibel. lower condensor a bit until image becomes sharp. at least center the light-iris, close the illumination iris as much as possibel and center it
This is a great video contrasting the two diaphragms and thier uses and interations. Some cheaper microscopes have Köhler illumination too (eg. AmScope B690 costing €600).
Muchas gracias
Really so interesting thank you very much .
Tq so much sir with send to oher vedios such a wonderful explaination sir tqs for ur teaching... 🤝🤝 once again tqs sir
This is a really wonderful video and do help me a lot. when observing the wool fibers, it's really turning off the condenser or it's the iris diaphragm closed? Got confused in this part.🤔️😄
Hello, in my opinion the microscope is in very good condition, only a small thing, almost irrelevant, the slide potentiometer can be cleaned because when setting the light, the light jumps but after heating the microscope the problem disappears :). We watch and listen to all your reviews, they are very helpful, thank you!
Very helpful video. I just started working with a Zeiss Inverted microscope, so the condenser is located on the top instead of the bottom. Does it still serve the same function as the condenser in this video? It's Iris Diaphragm looks a little different than the one in this video as well.
I have an old microscope with iris diaphragm attached to the condenser. I'm thinking if I can remove it and install it as the field diaphragm for the light of my new microscope.
Sir can u show an heat shock bacteria on microscope
Very informative video, thank you! I have a question about the condenser - should it always be placed in the highest vertical position, or is there any advantage to adjusting the vertical position? In my case, my microscope does not have Koehler illumination.
Lowering the condenser by 1-2mm can move dust on the condenser out of focus, so the image looks cleaner.
Hi,
Again, a very informative video, thank you.
However, one thing is not clear to me and and isn't mentioned in the video.
Maybe it is such a silly and evident question that you even didn't think of mentioning it, but still I'm struggling with it for some time now.
Microscopes are equipped with an Abbe-condensor.
Köhler illumination is said to be superior above - what was it? "critical illumination" - so Köhler is the method to go for.
Is there also something like a Köhler-condensor, or is the difference just the way of using / setting the Abbe type?
Could a person use opaque disks with different size circular cut outs to effect a field diaphragm? This would be used on microscopes with a built-in illuminator of course. I don't think I've seen this discussed.
hey, did you end up trying this? Sounds like it would be used in a similar way as a dark field filter (ie you'd have one disc per magnification)
Wieso muss denn der Kondensor zentriert werden. Seine optisch Achse sollte doch in jedem Fall
mit der optischen Achse des Objektives uebereinstimmen und nicht mehr veraendert werden. Wohl aber
sollte die Leuchtfeldblende zentrierbar sein.
Das bedingt auch immer eine zentrierbare Punktlichtquelle.
Could you please explain difference between Abbe, Achromat, Aplanat, Strain-free condensers?
Very interesting video, but it was indeed short and quick. I am sure you could go into much more detail. Maybe when your new channel has grown a bit?
Te están compartiendo información y trabajo y te pones de exigente
How to raise condenser where is it shown
There is a knob or lever beneath the stage to raise and lower the condenser.
My microscope's objectives have apertures listed, but my condenser's iris doesn't. Do I just wing it?
Just use the setting that gives the best subjective image quality. This might differ from specimen to specimen.
What (microscope) camera did you use in this video? Do you use same (microscope) camera in every video?
I use a Digital Reflex (DSLR) camera with a separate adapter. I use the same camera always, but sometimes I use an adapter for a smartphone when I need to take a microscope along somewhere for portability.
@@MicrobehunterMicroscopy I have had some issues with DSLR-adapter. I get some kind of white spot in the middle of the picture. Any idea why this happens? Adapter is a tube that goes in ocular tube and has mount (Nikon-F) for the camera.
I know of this problem. I can remove this bright central area by closing the Köhler diaphragm on the lamp. The white part seems to be stray light. Köhler limits the light only to that part that actually is observed. I once wrote an article about this:
www.microbehunter.com/kohler-illumination-to-reduce-reflections/
Now: most microscopes do not have Köhler. I suggest that you try to make the aperture of the lamp smaller and see if this works (black paper with hole over lamp).
Iinterestingly I found this effect in only one of my two cameras (the one with the full format sensor). I remember that I had a similar problem a long time ago when I used analog film. Remove the camera and put a piece of paper there where the sensor should be (room dark) to see if this also has a central bright spot.
Maybe I missed this.. microscopes can have both Condenser and Koehler (Köhler) diaphragms ?
Or need buy as separate? :)
Yes. condenser diaphragm is much more common and recommended (missing in beginner's and chrildren's microscopes). Köhler is present in high-end microscopes. Depends on the microscope model if the company supplies them. Some microscpoes can not be upgraded to Köhler, as already built in.
Hello, I would like to explain immediately that I am a novice in these matters, I would like to buy my daughter a Christmas surprise in the form of a part for microscopic observation Olympus BH2, for example: Olympus 1.25 Phase Contrast Condenser BH2 CH2 Microscope 10 20 40 100, for which observations she can is it useful? Apart from this part, is there anything else needed to comment on the whole 🤔 Thanks and Best Regards
1. The Olympus BH2 (if the condition is good) is a very good microscope. 2. Phase contrast drives up the price significantly, but is not absolutely necessary. Good for viewing bacteria. You can use regular brightfield with it as well. 3. the 4x objective is missing, but this would be more important than a 100x objective. 4. with used microscopes, it is not uncommon that the knobs become difficult to turn as the lubrication oil becomes solid. Do not force turn if this happens, and then get the microscope serviced by a company. For the BH2 it is worth it, as it is such a good microscope (will last forever if taken care of). With this microscope she can observe all of the things that a hobby microscopist would want to observe - except objects that are better seen with a stereo microscope. So it is more a question of microscope type than the features.
@@MicrobehunterMicroscopy whether the image obtained with an expensive phase capacitor and expensive lenses is worth this replacement🤔
I'm a little unclear. My microscope has a an iris in the condenser and also one on the light source. Does this mean it has Koehler illumination? I guess I'm just not that clear on what Koehler really is.
Close the iris on the light source completely use a low power objective (4x). If you can see a circle, then raise and lower the condenser if the circle becomes blurry, then you seem to have Köhler. Put a paper above the condenser (like in film) and open/close the iris. If the width changes, then you have Köhler. Köhler allows you to adjust the light so that it only shines on the small part of the specimen slide that you actually look at. Reduces overheating, stray light and the optics of the Köhler make sure that the whole field is completely evenly lit. One could put a diffusing glass over the lamp to make it evenly lit, but this reduces light.
@@MicrobehunterMicroscopy You, sir, are gentleman and a scholar. Thank you.
@@MicrobehunterMicroscopy I really need info about this issue because I have an older American Optical 110 Microstar microscope that I'm trying to become familiar with its features and learn to use. I found your description of Kohler to be unclear in the video, and will try watching it again. However, your further explanation above helped a bit. I have a knob on the base of my microscope that says "Diaphragm". Do you think that means I have Kohler, or is it impossible to tell except possibly by following your instructions above? Many thanks.
@@eqlzr2 is the diaphragm right beneath the stage (does it go up and down with the stage when you focus) or is it on the base of the microscope right above the lamp? case 1: condenser, case 2 Köhler. It is unlikely to be köhler if you do not have a condenser (unless the condenser was removed). Put a paper into the light beam and look at the changing shape of the light. If it changes in angle, then it is the condenser aperture diaphragm. If the width changes, then it is Köhler.
@@MicrobehunterMicroscopy Thx very much indeed for your prompt, helpful reply. I did a little further research and found an old AO 110 Microstar manual. There are two diaphragms, one right beneath the stage as you described, but also one in the base of the microscope in the light-path from the halogen lamp. The manual says this diaphragm arrangement in the lamp light-path is equivalent to Kohler. Terrific. ;-)
Does a beginner need a condenser for his first microscope?
Difficult question and it depends. Young kids probably not. But as soon as you start to make pictures, you will appreciate it. Buy one without a condenser first, as they are cheaper and then after a few months one with a condenser.
@@MicrobehunterMicroscopy ok, thanks. I went ahead and got one with a condenser.
close the Koehlerdiaphragma...DIC is also only a interference