I've been studying scanning electron microscopes quite a bit but can't seem to get my head around why we need objective lenses.
On paper I don't see a reason, if we would want to focus the electron beam in 1 small spot, why we cant put our specimen directly in the focal/crossover point beneath the condenser lens.
Why do we bother with the lens aperture and the objective lens behind it?
After reading in about 3 different sources I think I finally understood a basic concept of optics. That the condenser lens and objective lens are supposed to work together. I can't quite say why but it seem that neither lens could do the job alone. We always (? not sure here) need both to focus the beam nicely in 1 spot. Can anyone give me some insights into this? Source