In article , Me
wrote:

Nikon also has the issue that with different flange distance, it might
be a good time to revise the F-mount system, but need to do that
maintaining some backward compatibility, but also with a good eye to the
future.

what are you talking about different flange distances?? all nikon slrs
have the same flange distance and there's no need to change it.

Well, there's an opportunity for them with mirrorless to reduce the
flange distance on the body.

that would likely be a new line of smaller lenses, unless the
mirrorless is full frame.

Of course they could just whack an F-mount
on it, and you could use a standard extension tube with electronic
contacts and mechanical stop-down mechanism. But there are a few good
reasons why they might want to change it:
F-mount is narrow - there's no room for the electronic contacts to fit
beside the large rear element, hence while they make f1.2 lenses,
they're manual focus with no "chip" because there's no room for the
contacts.

who cares. the main reason they don't is there's no demand for it.

the days of needing f/1.2 lenses are long, long gone. that might have
made sense when iso 400 was very grainy and anything beyond that was
'artistic' it was so bad.

today with digital, iso 1600 is fantastic and iso 6400 is amazingly
good. even f/2.8 lenses are not that important anymore.

The mechanical stop-down linkage is also an issue - look at
the problems with liveview implementation and changing apertures. They
kind of "fixed" that with the D800/D4, but it's a complex servo stepper
motor (IIRC) in the body, but this created other issues (with video
IIRC?). A mirrorless will probably effectively be in "liveview" mode
when you turn it on. Electronic (in lens) aperture control is a
simpler, better solution these days. Nikon already implemented this is
the TS-"E" (E for electronic aperture in this case) lenses because of
the difficulty of a reliable functional mechanical linkage accommodating
tilt and shift. Problem is that the electronic aperture won't work
unless you have a recent pro-level Nikon camera.

obviously, changes in the lenses need changes in the cameras. af-s
won't work with cameras that predate it. stabilization won't work with
cameras that predate that either.

Nothing inherently wrong with F-mount for today's cameras - apart from
those minor niggles, but times are changing, and as much as I believe
the DSLR still has a few years left, it's going to be doomed eventually.
Whatever they do, they need to be very careful. I suspect that part of
their reason to hold-back on larger format mirrorless cameras will be to
make sure that when they do make the move, they do it right.

as i said they can come up with a new line of lenses and have adapters
for legacy lenses. they don't have to change the f mount at all.