I'm wondering what lens you guys keep on the M4 when you're just walking around? I wanted a small and light zoom, covering 35mm wide angle up to a mild telephoto. There is also a consideration that if I mount one of the newer AF lenses from Nikon, they no longer have an external ring for aperture adjustment. An issue for me though, is I have three "current" Nikons, my F4, my D750, and my Df.
I read what Ken Rockwell and others had to say about lenses, and then went hunting through the KEH website, KEH.com, looking over a few zillion lenses. I settled on Nikon's "AF-S Nikkor 24-85mm 1:3.5-4.5G ED VR". Long name. I haven't yet gone walking around with it, but I did some testing on the F4 and everything is working as expected. I need to shoot in (M)anual or (P)rogram mode, as I can't set the aperture manually. A bigger reason for selecting this lens is that I can use it for the same purpose when I'm using my D750 or Df - all I normally use with them is prime lenses.
This new lens is "heavy" compared to a prime, but very light for what it is, a zoom. It's bigger than what I wanted, but smaller than having extra lenses in my pocket or bag. If I want to go shoot birds, it's totally inadequate, but I've got my other lens..... but for that kind of photography I'll probably be shooting digital. I think "film" will be most useful for me for landscapes, and scenic shots, when I will take forever to decide what to shoot Right now, I'm only shooting B&W film, but I expect to start shooting color if I'm pleased with the B&W.
Bottom line, I will be happy or not depending on how my new images compare to what I did in the 1960's, with one lens, and only B&W film in my Leica M3. The film will be professional developed, scanned with a Plustek scanner set to either 3600 or 7200dpi, then edited in DxO PhotoLab4. As long as the Nikon lens is up to it, I'm 99% sure the camera body is.