MicrobeHunter.com Microscopy Forum

From my eyperience white lithium grease is best for applications where water resistance is needed (it raining again here...). I use it for bicycle and motobike parts mainly. From my experience it doesn't adhere very well to the surfaces and feels somewhat grainy. Compared to instrument greases it wo...

The main purchase argument for new versions of image editing software is the support of newer cameras raw files. You simply can't use the old software for raw conversions of cameras that came to the market after the software version. Without this trick the software companies would earn a lot less mo...

Have you looked at these crystals with crossed polarizers too?

Bob

For dovetail guides and other lubricating points with a lot of surface the grease should be quite soft. Special greases for this application contain animal fats that make them stick better to the surfaces. With stages one tries to put the damping in the knob and have the stage itself move freely. Th...

Hi Rob, when you use the 40x objective - don't you get a sharp picture or can't you see any light? The 25x eyepiece is mostly a marketing gag: When you magnify the image of the objective this much you see things bigger but not sharper than with the 10x eyepiece. You may try whether it appears useful...

Hello Apo, I just had a look at my Leitz EF 4 /0,12 objective with 45mm objective design. It is a semiplan achromat of typical small design for this type of objective. The free working distance here is 24mm. It is parcofal with the stronger objectives. So 5mm for a 3.5x objective is a quite small wo...

the lens formula is 1/f = 1/i + 1/o where f is the focal lenght, i, the image length (160mm or OO) and o is the distance to the object. The term 1/i is very small so we can overlook it. 1/f equals roundabout 1/o So f is roundabout equal to o BUT 32mm is not roundabout equal to 5mm! I think that the ...

I looged out, logged in again, Kurts pm is still not visible for me.
Perhaps this system tries to decelerate our lives to a more healthy speed level?

KurtM wrote:(MicroBob, I sent you a PM)

I didn't receive it. I sent you an e-mail instead.

Is there a common problem with PMs on this forum? I had it more than one time that PMs were transmitted with a delay.

My vacuum setup: A Mightyvac hand pump, originally intended to drain motor bike brakes, and a frame with a seal to put upon one single slide. The screw has no meaning, it is just to keep the bandsawn frame together. The glas is 4mm acryl. I do 5 pushes, wait a couple of seconds, then press the relea...

There is a second document on measuring refractive indices: http://www.mikrohamburg.de/Tips/T_Brechungsindizes.html Pictures are in separate links in the document. Maybe this helps. For a manual of the Refraktometer you might look here: http://www.mikroskop-online.de/Zeiss%20Jena%20BDA.htm It really...

You're welcome, MichaelG! Diatoms don't have all the same refractive index and their structures are different. So the necessary refractive index of the mounting medium will vary too. For some diatoms a r.i. of >1,65 is really needed to get a good contrast, e.g, Amphipleura Pellucida. But for many di...

Merry Christmas to you all! Hobbyst46, you might think about this: Normaly everything gums up in the same speed. Due to the gear ratio one often don't recognise it in the fine focus movement immediately. When you bodge your coarse focus to work halfway good you might wreck you fine focus later becau...

Without oil immersion the condensor cant't go beyond n.A 1.0. This is quite a difference to the full n.A. of an oil immersion condensor. The effect will probably be the same as when I use a 40x objective and close the condensor diaphragm to an n.A of 70% of the nA of the lens. The contrast and depth...

Many microscopes have a stop that limits the movement of the condensor. It might be adjusted a bit conservative so that you can't turn the condensor high enough. Normaly it should be able to just touch the slide.

Hi Matt, your grey background - does it occur together with a verly light object? The metering system of a camera is adjusted to give images of medium brightness. It tends to get exposure wrong in dark field microscopy. Dark field enhances all dirt in the slide and in the light path. When you see a ...

Just for the information: What happens when the knob at the back is pulled? Is it a 100/0 va. 0/100 trino? Or is there a position, where you get a visual image in the eyepieces and can take a picture at the same time?

Can you post a picture of the situation?

Hi Andy,
I don't know this microscope but a sliding dovetail should have the same width front and back. Do you have access and a measuring tool to check this? It might have been forced apart in the past when a condensor became stuck from gummed up immersion oil.

Bob

I think for a project of this price range it would be useful to precisely set the aims and give priorities to them. - Is this going to be an apparatus that will be used by Ashly, the inventor, alone or is it to be expected that superficially trained personnel will use this apparatus? How much manual...

I don't need and eyepiece at all. You might not need one to look through, but typical microscope optics are calculated in two ways. Either: A) Objective, correct tube lenght, correct eyepiece for this objective +(whatever you need to get your picture) B) Objective, correct tube lens for this object...

In microscopy we don't look much for magnification but for resolution of detail. The measure for this is the numerical aperture that is given on every objective. A typical 40x achromat objective has an n.A. of 0,65. Taking into account the resolution of the human eye, the image of this objective can...

Hi Ashly, I think you will have to specify in more detail what you are looking for. E.g. do you want the blood cells "in the picture" or do you want to have certain details of them resolved? Can you offer a picture that shows the amout of detail you need and can you specify the area you are looking ...

Thank you for showing the part and the history behind it, apochronaut! At this point of time the light microscope had been an important research intrument for some decades and the work of Robert Koch and Louis Pasteur had depended on the invention of the homogenous oil immersion. I can imagine that ...

I think that a different camera app can not adress the problem with the focusing mechanism. As far as I know these lenses don't know how they are focused at the moment before the image capture. An electrical signal is changed through a cycle and the picture is taken when the result seem best to the ...

Phone cameras usually don't have a defined focus position. When you take a picture, the camera always has to focus again through the whole focus range. This makes it impossible to do focus stacking. Correct me if I'm wrong or if there are exceptions. The cheap microscope USB cameras have either a ch...

Your phone will probably alread offer a quality that is not so easy to beat. I would just start with this. Camera adapation is a difficult and expensiv topic on it's own.

I think one point has not been mentioned: Ernst Abbe found out that the magnification should not exceed 500-1000 times the n.A.. This is magnification of objective, eyepiece and tube factor . Binocular tubes usually have a tube factor between 1,0 and 1,6, so may be a 10x eyepiece and a 40x objective...

BTW, how do they arrange diatoms on a slide like that? Here: http://www.mikrohamburg.de/Programm/Protokoll_20170218.pdf you can find a beginners tutorial on arranging diatoms in german language and a link to a french video on the topic. I have to admit though that I'm no expert on this topic by any...

For diatoms an oil immersion objective is really useful. In many cases a 0.9 dry condenser would be good enough for diatoms with an 1.3 oil immersion objective. But in some cases you would need all the resolution that is offered by the objective. So an oil condenser would be a good buy for you. You ...