There is plenty of "work" to be done regarding lens design: from what I've heard, there is a delicate tradeoff between designing a lens that has pleasing bokeh

There is plenty of "work" to be done regarding lens design: from what I've heard, there is a delicate tradeoff between designing a lens that has pleasing bokeh (smooth MTF when out of focus) and designing a lens that is sharp when focused--I've heard that to do the former, you basically /need/ spherical aberration, but to do the latter, you need to remove as much spherical aberration as possible. I believe this is what people are referring to when people say modern lenses are too sterile and that the old lenses (which because aspherical elements basically didn't exist, had lots of spherical aberration) Also, a decent zoom lens design is still very difficult. It basically needs to be designed trial-and-error style, and there's a LOT of knobs to tweak, as the zooming affects all kinds of figures of merit. Nowadays it's basically fully automated with optical solvers (they use raytracing, but in one axes, but they solve for things like spherical aberration, chromatic aberration, etc etc) Just because you have asphericals doesn't mean you automatically solve all your problems. The onion-ring bokeh effect is still unfortunately an issue with asphericals. Also one thing I really wish would happen is open source lens correction get better. It's currently absolutely shit.