MicrobeHunter.com Microscopy Forum

Hi Hans,
I would keep this practice. Of components with identical designations there are several versions and sometimes they actually selected optimal combinations.

Bob

Hi, thank you for this thorough test! To me this looks like 19mm field of view. For flat objects the basic achromats are just about good for the central 10mm of the field of view. The 40:1 achromat also seems to have a lot of pincushion distorsion - is it possible that the autofocus of your phone fo...

Hi Glen,
thank you for the link!
Proper diatom literature is quite expensive and it is nice to have at least some more comprehensive PDFs at hand.
Don't spend all the bingo money all at once!

Bob

I think it is also a question of the time of establishing the company: Zeiss founded his company (just one apprentice) in 1846. Germany was not united then but a puzzle of small kingdoms auf you couldn't move quite as you liked. Also when I think about microscope manufacture there are a lot of other...

Sir wrote: ↑

Fri Jul 10, 2020 11:43 am

I'm unsure how to check the field size.

The 4:1 objective places an image of 4x linear size inside the tube. There it is picked up by the eyepiece and further enlarged. When you would take a ruler with 1mm scale you should be able to calculate the field number of the used eyepiece.

Bob

The term "PLAN" should ideally be accompanied by the size of the planar image. Over a field of 10mm many achromats are fairly plan, over e.g. 25mm not so. Do you know how big the field is that your camera captures? Did you cover the paper with water or oil and a cover slip? I'm sure your comparison ...

Hi Phil,
Zeiss didn't stop at all, I'm sure that they still obtain much of their optical glass from their sister company Schott.

Bob

That is a condenser for the Zeiss Standard Junior with sleeve fit. This microscope was intended to be used with a mirror and a light source a bit away. It might not be the best choice for a microscope with the light in the foot. I would suggest an Olympus condenser. If you need more parts you might ...

With Leitz 160 and 170mm there are 2mm tube length difference. This leads to a little less parfocality for the weaker, not the stronger objectives.
For a newbie I would recommend to keep using ordinary achromats until a bit of experience in slide making and microscopy setup are gained.

Bob

Hi Aaron, I think the combination of computer and optics has lots of future. Especially in the form of an open source project where many people contribute to the further development. Most 160mm objectives are calculated with a residual chromatic error that is corrected by the eyepiece. So if your ca...

Hi Luca, by moving or turning individual components you can single out the source of the obstractions. It is true that imperfections and dust show up more when observing with higher powered objectives. These also show faults in eyepieces or in camera objectives. The obstractions might be mouche vola...

Hi Sarah, to clean you front lens you can use surgical spirits or lighter fuel. Generally the image content of high magnification microscope images is low, just a couple of megapixels. It is very important to avoid mirror and shutter shock as they blur the images. Some cameras allow shock free relea...

Hi together, here one more photo, this time from the side. I wasn't able to do a closer identification so far, it is not the ordinary variant. The TG4 has a bayonett in front of the objective which is normaly covered with a ring. There is a 3D model that fits this bayonett on Thingiverse, but the pr...

Ho together, here a potrait of a horsefly, taken with an Olympus TG-4 outdoor camera in "microscope mode" at f=14. The photo shows how much is possible even with limited equipment. This is a rugged compact camera I use while paddling. Image quality on these cameras is always limited, probably becaus...

I think the importance of arranged slides has recedet: One can assemble the arrangement from individual photos and gets a result that can be shared via internet. But separating and mounting individual diatoms is still nearly as useful as ever. I used skin fat on target surface and seal hair as I thi...

Hi Charles,
so the water contained diatoms until about the 45th minute?

Bob

Hi Doron, thank you for the explanation! Building this ingenious setup must have taken quite some time. And there are probably few other designs that include a micrometer as well as Lego bricks! :lol: For my attempts at diatom arranging I used a simpler setup but was not that happy with it. It made ...

Hi Doron, congratulations to this nice setup! For some samples it probably is much more worthwhile to pick good frustules out than to try to clean the sample to a high grade. Do you use a sticky substance on the tip of your fibre? Is the fibre attatched to the objective and moves with the focussing ...

So what is diatom cleaning by incineration good? Find the answer yourself, here an image of a Tabularia diatom ensemble doing a half roll.

Hi Jan, I can't watch the video due to mobile internet limits but I can recommend a suitable identification book. Since you are from the Netherlands you can probably read german to som degree? Here in Germany we use "Das Leben im Wassertropfen" as an amateur fresh water ID book. An older issue will ...

Hi Doron, I recently read an article where they specifically compared inicineration and chemical cleaning for low silicified mediterranean sea diatoms. They found much less broken frustules after incineration cleaning. The research was probably directed towards identifying and counting and they prob...

Hi together, in the past I have cleaned diatom samples in a small oven at 450 degree C for 30 min. Frustule pairs and algae groups stay together and the frustule structure is visible very clearly. Now I'm experimenting with more compact setups with stainless steel plate, alcohol stove, micro gas tor...

Hi together, I did some experimenting with my diatom cleaning by incineration. This time I used a small gas powered heat gun and directly applied the heat to the cover slip for a short time in short bursts from both sides. This was long and hot enough to char the organic matter, but it didn't burn e...

It's a typical single 3W Cree LED, powered via USB cable over a 0,47Ohm resistor in row with a wire potentiometer. The USB power source is a Bosch GAA 12V with batteries from 2 to 6 Ah.

Hi Jan,
that is a nice desmid you found there! They are also nice objects for Rheinberg illumination.

Bob

in fact I brought the mirror, it can be set onto the light outlet in the foot. I'm very used to built in lights so I want to try natural light with the Junior too.

With very small objects it is optical vs. digital magnification. But in most cases I too use max. the 1,6 setting.

Hi together, here some Asterionella diatoms. Cleaned by incineration, milk carton dark field stop on light exit in the foot. 16:1 plan. I brought the Junior which proves very nice with bright battery illumination with 12V Bosch power tool battery and USB converter. What I miss from the Phomi is the ...

Photo made with the 40:1, oblique light. In the tips you can see crystals inside the end vacuoles. Closterium is found most frequent, some species are comparatively resitant to pollution. For the photo it turned into a nice even position. To me it looks quite healthy.

Hi together,
here a couple of first photos from the micro life of the lake we have gone to.
Desmids tend to orient lengthwise in bright light as can be seen in one of the images.

Bob