It is worth it?

[Greg Howald]

Is that robust microscope with its 25mm objectives gonna make me really glad I bought it, or is the result gonna be much the same as my smaller scopes?

[PeteM]

There are three pretty noticeable differences with the better quality Nikon CFI 160 (say, Plan Fluor) or Leica DM (say, again, Plan Fluor or up) objectives with 25mm threads. First, they have excellent contrast wide open. Second, you can get a better tradeoff between resolution and contrast (by adjusting the condenser iris) due to the higher numerical aperture. Third, you have the option of near panoramic fields of view - around 25mm field number or so - if you get a compatible head.

That said, the significantly higher price when you already have a decent microscope (say, a finite Olympus BH2 or Nikon Labophot/Optiphot) could make the answer to your question "no" if you stick with brightfield, polarization, and darkfield. I think you'd want a bargain on the new scope and be able to sell your old one for a good price to justify the upgrade.

Should you use that extra money to add DIC, I suspect the vast majority of those users would say "yes." This is particularly true if you want stunning images rather than, say, want to ID various protists.

[Scarodactyl]

It depends what you're doing and how it's equipped. My E800 is absolutely amazing but I have to admit I don't use it that much since I rarely look at alides and haven't ended up starting.

[apochronaut]

Most microscopes in use are R.M.S. with achromatic objectives. A microscope with M25 objectives can be an achromat too, although there is a higher incentive with ultra wide field scopes to fit them with fluorite or apochromatic optics. That's where the difference lies, in the quality of the optics, not so much the scale of the frame and fittings.
An R.M.S. scope with a 20 or 22mm f.o.v. with planapos can bring a whole other perspective to an otherwise modest instrument.No need to spring for a big scope, just the right optics.