So I spoke with the seller and got the following information:
1) Two Olympus PC (Phase Contrast) objectives 40X, 100X
2) TWo Olympus DPLAN 4X, 10X and Olympus 40X PLAN objectives or
three Fisher Scientific PLAN Obj 4X, 10X, 40X.
There seems to be a discrepancy between the photos and what the seller is describing? The first and second photos show different objectives.
The second photo appears to show three shiny phase contrast objectives (red rings around bottom) -- at least one is clearly Olympus and the others appear to be. The SPlan Olympus have a shiny body (as appears in the photo) while the DPlan have a more satin finish. One way to tell is that the 40x SPlan has a numerical aperture of .70 while the DPlan is .65 in both regular and phase objectives.
Seems the seller is saying you're only going to get a 40x and 100x phase contrast objective (despite picture #2 showing three phase objectives) and they will be plain Olympus achromat, not Phase SPlan achromat which have a wider field and higher numerical aperture?
For pond critters, I think you really want at least one phase contrast objective in the 10x to 20x range. Starting at 40x is too high in my opinion and I suspect you'll rarely use the 100x.
The scope itself, assuming it's a BHS as advertised is a very good model. The problem is that the first picture appears to show a less valuable BHTU model with an inverted nosepiece. Hard to know exactly what you're getting?
All in all, I'd be inclined to pass on this microscope at that price and with some uncertainty about what you're getting. You might try a lower offer given that it apparently only has two phase objectives of somewhat modest quality? But be sure it's a BHS model with the 100 watt lamp, adjustable stage, and removable nosepiece.
As for the non-phase objectives being offered -- the DPlan Olympus regular brightfield objectives or the Fisher Plan are pretty standard lenses - decent image quality (even the Fishers, if the plan lenses made in Japan for their "MicroMaster" scope) but nothing special.
Don't know how many posts you need to be able to send messages -- but when you can, the offer of a rambling guide to microscope brands and models is yours for the asking.