What to buy. Advice

[Glot]

I am new and I know nothing. I have a zoomable stereo and a Leitz compound. The stereo is great fun, easy to use. It apparently goes from 7 to 45 mag. The focus is too coarse at higher mag but manageable. Maybe one day I can modify it. The advantages are a huge working distance and at lower mag, very broad focal range. I use it for hand specimens of rocks. The leitz is so smooth compared to it. I use that for thin section slides. The working distance is small, even on lower mag. When I put a slide under the stereo, at an estimated 10 x mag, I get a good view. Very wide end 3D. Then if I put the same specimen under the leitz at x4 mag, I get a very small view but wow, the resolution is so much more. Less magnification but higher resolution. So, even if I crank the stereo up, I won't see as much detail. I use them both but they are totally different. The stereo is still the most fun though.

[75RR]

Perhaps an intermediate objective between the 4x and the 10x.

I believe Leitz made a 6.3x

[MicroBob]

You have observed right: Usually stereo microscopes have barely the needed resolution for acceptable visual oberservation, less than a normal microscope objective offers. This has to do with the aim to offer a good working distance with not too wide and expensive optics.
At 40x combined mag a typical stereo microscope has an n.a. of 0,08. A typcial 4x compound microscope objective has an n.a. of 0,12, much better than the stereo.

If you want a higher resolving stereo: They are available but extremely expensive.
Compound microscope objectives go down to 1:1 (Zeiss Plan 1)

Bob

[Glot]

I was trying to explain in an uncomplicated way from one beginner to other beginners.