Currently the lens adapter market has simple "dumb" lens adapters, as well as "focus confirmation" adapters that cause the AF confirmation system, aka "the green dot" and or the "chirp sound" to be enabled when using adapted lenses. Focusing is still accomplished by the photographer turning the focusing ring on the lens. As far as lens diaphragms: all Nikon lenses use a mechanical lever to open and close the lens diaphragm. This mechanical system is what allows a 1959 Nikkor lens to have automatic aperture operation on say, a Nikon D40,D60,D3100, or D5100--it is a purely mechanical aperture actuating lever on each Nikkor or Nikon lens. MOST Nikkor lenses have a mechanically controlled f/stop ring on each lens barrel, but the newer lenses, the Autofocusing, G-series models, have NO lens f/stop ring on the lenses, so they are like Canon EF or Minolta/Konica-Minolta/Sony A-mount/Alpha-mount lenses. The very,very newest lens adapter for Nikon lenses to Canon bodies is a limited-production model that allows for adjusting of the Nikon G-series type lenses on Canon SLR Cameras, and was spawned mostly due to a demand to use the new Nikkor 14-24mm lens--which is actually a noticeably better optical performer than even the Canon 14mm f/2.8-L lens, and far better than Canon's 24mm f/1.4-L lens..it's just a simply incredible lens....an ultra-wide, full-frame capable lens that out-performs almost any Canon wide-angle prime, and any Canon zoom, and basically, is better than 90 percent of Nikkor wide primes or zooms ever made...Nikon's "old-style" 16,18,20,24 mm regular-speed f/2.8 primes are not anywhere near as well-corrected as the new 14-24 zoom is--but then again, the "regular" ones are now 20-25-30 year old optical designs.
I suppose it would be theoretically possible for a new kind of smart adapter to be made, like one that could convert the orphaned Canon FD-mount manual focusing lenses to 1) autofocusing and 2)some type of automatic diaphragm operation via contacts and a servo motor system inside of the adapter, as well as some glass elements to make infinity focusing possible with the older FD-mount type lenses. The signals the Canon EOS bodies send out could be read, and could be programmed to activate a small motor that would mechanically close, then re-open the mechanically-actuated lens diaphragm found in manual focusing Canon lenses, after each exposure. I think however that the chances of this type of thing being made are about as high as the chances of pigs flying some day. Nikon 's TC-16A proves that a converter CAN CONVERT manually focusing lenses to FULL AF operation on an AF body....so that concept is proven and a real product exists. But that is also a one-system product, that has the same type of f/stop actuation mechanism in both the old, manual focusing lenses, the older AF lenses, as well as the very,very newest lenses made today. A multi-platform smart converter would be much more difficult to design.
