I bought my first microscope a couple of days ago, I was checking a couple of new cheap ones but they are overall still above the budget I had set, so I ended up buying an used one.
It's an old Carl Zeiss microscope that came from a lab that closed and auctioned its assets, it was bought from a guy that was interested in other machinery but had to buy the whole lot. It's a risk buying used when I don't know a lot about the field, but it was reasonably priced (225 euros) for something from a reputable manufacturer and it looked that it was used but looked after properly.
Here it is:
It is marked with "West Germany", so can I assume it was built before 1990? The 10x eyepieces look a bit worn on the outside, but they have zero scratches and the anti-reflective coating is spotless. What does the 1,25x marking mean, that there is an additional magnification other than the eyepieces? The stage looks very worn (and it is) but it appears to have been carefully maintained, it is still clean, properly greased and there is no "play", everything feels tight with the right amount of resistance to movement.
It came with two "older looking" 10x and 40x objectives, they look worn but the lens are clear and the images are not hazy, they are also all spring-loaded, which is nice on the larger magnifications, I remember breaking a couple of slides in school because I got lost while focusing and was too lazy to start-over:
The 100x objective is also from Zeiss but it looks aesthetically different, it is marked NEOFLUAR 100/1.30 Oel, the front lens looks clear and I can focus with it but the images are a bit blurry, I assume it is because of the lack of immersion oil, which I didn't yet buy, so I didn't have the opportunity to test it adequately:
My first doubt is this one, it also came with a Nikon objective in a Nikon cup:
It doesn't feel as sharp as the 40x but I might not be using the adjustment collar properly. I didn't really find a lot of information about it, can someone give me an idea of it's value? It is in pristine cosmetic condition, if it's worth something I will try and sell it to buy more supplies, similarly named objectives seem to be worth something, the lack of information might mean it is an older model or that it is not very good and people are not looking for it.
The second doubt is this part that came in a wooden box:
The domed mirror underneath makes me believe this is some sort of darkfield condenser, but I'm not entirely sure, I've tried to use it instead of the default condenser and the resulting images look really dim, although I didn't use any colorants.
The last item I'm not sure of it's purpose, the name suggests blue but it looks more neutral than blue, it kind of reminds me of a neutral density filter, but it is marked 1,0 and is way more dark than a photography ND1 filter:
So, here are the organized questions:
What does the 1,25x marking in the head mean, that a 40x objective with the 10x eyepiece end up being 500x?
Is the Nikon objective worth anything?
Is that device in the box a darkfield condenser?
What is the purpose of the filter (aprox. 32mm diameter)?
Regards, and here is a bonus picture of my blood taken with my phone held directly in front of the eyepiece (not stained, as I don't yet have colourants):