Why my background is not clear

[len]

Hi,
Does anyone know why do I get this colorful background when using my scope?


Photo above is of clean drop of water inside cavity glass slide over bright light condenser.
I get the same background with x4/160 0.17 and x10/160 0.17.

Thanks

[Pau]

Maybe your condenser is imaging a frosted glass in the illumination path at the slide plane (a very usual issue). Try raising or lowering a bit the condenser.

[len]

Thanks,
Problem solved