He was - you are right there, Mako.
But I had before promised SaintGermain to try to find the way to use the "Real time exposure" on the D7200 - if I could - and it seemed to me to "get in" the context of the question to mosswings -
that's why I was there
And I really tried not to mention the E-series - not to make that confusion
Yes, sorry for the confusion.
I understand that we can change in Manual mode the aperture in Live view, given that the lens has an aperture ring.
In exposuremode "M" - if they are AF-lenses - you can do it just as well in AF-mode. (Manual mode is a lot of things

) You can't use "A" or "S" exposure modes. (As far as I know.)
But now I'm intrigued by these new E-type lenses. Can we in Aperture mode and in Live view, modify the aperture and immediatly see the result ? Especially with the D7200 ?
Those "E"-type lenses are priced more than gold - only a Rockefeller would know
Yes - I'm very sure, it's possible - why would they make an electronically aperture (step down motor) in the lens, if not.
BirgerH.
3 big reasons for E-type:
1. videography. Mechanical aperture stopdown is not sufficiently precise to prevent flickering of the image as it reevaluates exposure. You may ask, why would anyone want to let the camera play with aperture during recording? Well, videographers wouldn't let it, but the general public would. Also note that proper video requires using a shutter speed fixed to the frame rate, so the only options for adjusting exposure are real-time aperture and ISO.
2. the mirrorless future. No room for an aperture lever in tomorrow's f-mount mirrorless cameras, assuming that it's an fM-mount with a short registration distance.
3. freedom in placement of aperture mechanisms and simpler mechanicals. E-type first appeared on tilt-shift lenses and moved to exotic telephotos. With a remoted aperture mechanical linkages are impractical. For less exotic lenses, a direct-drive micromotor is more space-efficient than a linkage.