MicrobeHunter.com Microscopy Forum

Hello everyone!

I'm Sandra, 25 years old and "new" to microscopy as a hobby at home.
I do know some basics about it because I work in a medical laboratory as a microbiologist, but ofc I don't know much.
I recently bought a Swift 380T Trinocular, because I want to learn more about microscopy and all the microbes around me as well as taking nice pictures.
I'm sorry if my description of my issue is not very clear - English is not my first language, but I try my best!

So my problem is the following:
When I try to focus my sample I always have either a focused mid-area and a blurry surrounding or the opposite. I can't get a clear focus on the whole "field of view"
This happens with all 4 objective lenses (4x, 10x, 40x and 100x+oil).

Im not really sure how to fix it or if it can be fixed. I know about "Köhlern" but I don't think that this is possible with this microscope because I can't move the condensor, right?

Thank you in advice for every help!
Sandra

Hi Sandra,
It sounds like your objectives are cheep achromats, what you need to have the whole field in focus are "plan" objectives; somewhat more expensive I am afraid.
Peter.

Laimura wrote: ↑

Fri Oct 15, 2021 5:31 pm

Hello everyone!

I'm Sandra, 25 years old and "new" to microscopy as a hobby at home.
I do know some basics about it because I work in a medical laboratory as a microbiologist, but ofc I don't know much.
I recently bought a Swift 380T Trinocular, because I want to learn more about microscopy and all the microbes around me as well as taking nice pictures.
I'm sorry if my description of my issue is not very clear - English is not my first language, but I try my best!

So my problem is the following:
When I try to focus my sample I always have either a focused mid-area and a blurry surrounding or the opposite. I can't get a clear focus on the whole "field of view"
This happens with all 4 objective lenses (4x, 10x, 40x and 100x+oil).

Im not really sure how to fix it or if it can be fixed. I know about "Köhlern" but I don't think that this is possible with this microscope because I can't move the condensor, right?

Thank you in advice for every help!
Sandra

Hi

What are you trying to focus on exactly?

Louise

PS the condenser is a helical focusing type which you twist to move up and down

Can you post a photo of what you See in the eyepiece?
That might be helpful in analyzing the problem.
Also, What eyepieces are you using?
Is it possible to get a clear focus using the camera?

You have non-plan objectives. The plan ones have a flatter field so you can see more in focus at once. Most clinical lab have bought plans as the tech efficiency is a little better with them. When I first started in clinical labs 40+ years ago, lots of the scopes had non-plan objectives due to the plans higher price. Even with plan objectives you will find the entire field isn't all quite in focus due the specimen thickness. Dried white blood cells in a smear can have 3+ levels of focus to see all the fine structure. And they're pretty thin!

Your objectives will work fine for you, you just need to get used to constantly using the fine focus to keep the part you are looking at in focus. It's easy, but takes a bit of getting used to. Even with the newer, pricier plan objectives you will notice most techs keep their fingers on the fine focus and constantly move it up or down. After a little bit it becomes second nature and you won't even think about it. I still do it with expensive planapo objectives.

Photography is a little more difficult, particularly if you have a moving subject. If it's not moving, stacking several photos digitally with different focus levels can eliminate the problem.

Hi! Thank you all for the answers so far!

Sadly I don't know how to attach some pictures for you, it always says that the Files are too large...No matter how often I compress the pictures

Hello and welcome.
It will help to own a stage micrometer slide. It should be relatively inexpensive (~10USD) and provide a very thin and flat and uniform scale across about half of the FOV (with the 10x objective). Useful for inspection and verification of the performance of the microscope: planarity, aberrations if any, sharpness of focus, and for calibration of the FOV and the measurement of the dimensions of the observed object.