ahsanford said:
It's own little plastic STM trinity you mean.
Stubbornly, as a stills guy, I want better built, internally focusing USM lenses for this platform.
I find, the current EF-M lenses have surprisingly good build quality. If future primes are built like the 22/2.0 - i.e. metal mount and "metallic" shell with very tight and nice build - it would be totally unwarranted to call them "plastic trinity". I am hoping for
EF-Mini Size, Mini price prime lens set ... including a super compact EF-M 80/2.4 STM IS, optically on par with 22/2.
STM AF drive is actually better suited to mirrorless hybrid-AF systems than USM, whereas Ring-USM AF drive is better for stills photography with mirrorslapper phase-AF and big, fat lenses with massive glass elements to be moved.
Personally, I'd much prefer EF-M lenses with AF only - without focus ring and no manual focus gear. Savings in production cost to be applied towards full weather-sealing. 8)
In conjunction, upcoming EOS M4 should also be fully weathersealed. After all, EOS M is my ultra-lite outdoor/alpine mountaineering/backcountry skiing gear.