[MJKoski]

Probably so. Well, such long term investments anyway and not that I would be able to purchase FF Z2 if it comes around :]

Z is coming to "affordable" price range these days. Will be interesting to see Fuji prices.

[Mistral75]

Then you're not going to like the Fuji GFX lenses which are almost certainly optimized the 645 crop frame image circle.

...nor the XD lenses of the Hasselblad X1D-50c, which are also limited to the 33x44 crop format. So is the Hasselblad X mount, by the way, and the Fujifilm G mount too.

[Zygonyx]

Exactly, at least there will be no image circle lens fail with those crop sensor systems....
Or the fail is sensor-size conceptual.

---------- Post added 23-09-16 at 08:38 ----------

Probably so. Well, such long term investments anyway and not that I would be able to purchase FF Z2 if it comes around :]

Z is coming to "affordable" price range these days. Will be interesting to see Fuji prices.

It has already been hinted that the Fuji body would cost around USD 10,000
So Pentax should keep the price advantage.

[RonHendriks1966]

...nor the XD lenses of the Hasselblad X1D-50c, which are also limited to the 33x44 crop format. So is the Hasselblad X mount, by the way, and the Fujifilm G mount too.

Size maybe makes the difference. The 645z is a large beast compared to the fujifilm and hasselblad for having the same sensor.

[Mistral75]

(...)
It has already been hinted that the Fuji body would cost around USD 10,000
So Pentax should keep the price advantage.

More precisely, (much) less than USD 10,000 with viewfinder and 63mm f/2.8 standard lens. So more on less on par with 645Z + 55mm f/2.8

[rrstuff]

If they introduced a mirrorless with a kind of AF that Olympus has (i.e. accurate and fast), it would probably answer all my troubles with Pentax.
I hope if it is a new mount, it will be able to accept K-mount with a fully functional adapter.

[monochrome]

It needs a complete redesign of the MF body. Larger sensor, larger shutter, larger mirror, larger mirrorbox, larger pentaprism. I am not sure if Ricoh can stomach that.

Starting with the 67 body . . . ??

[ogl]

For studio work - the size of camera has no any difference.

There are only two places where the size is important for mirorrless MF cameras. Street shooting and travel to extreme places, where the weight is serious problem.
But smaller size and smaller weight = weaker battery. Mirrorless needs more energy and more batteries for travel.

Small size, if your arms are big, is not comfortable too. There are many factors.

---------- Post added 09-23-2016 at 08:47 PM ----------

Then you're not going to like the Fuji GFX lenses which are almost certainly optimized the 645 crop frame image circle.

By the way, Leica S lenses could not cover 56*41.5 mm sensor too.
645 system from Pentax has advantage

[RGlasel]

645FF with 100 Mp, at 20K$

At that price it better have a name badge with more cachet than Pentax or Ricoh. As long as a MF camera has more MP than a 24mm x 36mm sensor camera, it doesn't matter if it has 50 or 100, professionals will spend money on glass, aspirational buyers will spend money on a brand name. Ricoh found a sweet spot in the MF market with the 645Z in terms of price and performance, the next steps will be to get money from 645 owners for new glass or flash systems.

[thibs]

If the D FA645 28-45mm were to cover the full 645 image circle, which it does not, it would be equivalent, in terms of field of view, to a 17-28mm on a 24x36 camera. Quite an odd combination. As other have pointed out, covering the full 645 image circle would have made the lens much bigger and more expensive (as if you asked a 16-50mm f/2.8 to cover the 24x36 image circle and not only the APS-C format).

The D FA645 28-45mm is non existant lens, you're talking about the DA645. As any DA, it is cropped lens (and you know that of course).
There's no surprise at all. Why even anyone would question that ?

[Mistral75]

The D FA645 28-45mm is non existant lens, you're talking about the DA645. As any DA, it is cropped lens (and you know that of course).
There's no surprise at all. Why even anyone would question that ?

Indeed, its name is DA645 28-45mm, my mistake. Otherwise, we say the same thing.

[thibs]

He's wrong but so are you AFAICT:

You remind me of the president of the scanner engineering company I once worked for. Everything was easy to him. But:

1. Semiconductor sensors are thicker and bigger than film: that pushes the shutter toward the lens, intruding into the space required for the focusing screen and mirror box

Quite dubious. It pushes electronics behind the sensor (toward the screen on the back). No way the other way around. IMO.

2. Even if there is an off-the-shelf 645-size focal plane shutter, it's almost certainly a different shape which likely changes the mirror box design (the old 645N shutter is obsolete with a 1/60 sec synch speed)

Why would anyone even think about keeping every little piece of the 645N is beyond me. That's your point I know.
Of course it should be changed. I see no real difficulties but of course it should fit and and such imposes redesign. Agreed (basically).

3. The 645N had only a 3-point AF system: if that's not good enough, the new camera needs a redesigned secondary mirror and mirror reflex mechanism.

Hum, Pentax proved 2 times already that the re-used APS AF modules. So no, no redesign needed (would be nice though).

4. Is the 645N's 6-segment light meter competitive: if not, then parts of the prism need redesigning

See AF point.

5. Is the 645N's viewfinder information display competitive: if not, then parts of the prism need redesigning

See AF point. Again.

Maybe the outward shape of the 645FF might look like the 645N but almost everything inside it will need to be designed from the ground up. That's especially true if the 645FF needs to offer competitive features in AF, metering, and OVF information displays.

No, not from the ground up. In the end though, just taking a 645N and changing a few bits here and there is not gonna happen (that was your point I think). But no, everything does not need to be a complete redesign.

[thibs]

Indeed, its name is DA645 28-45mm, my mistake. Otherwise, we say the same thing.

Absolutely, I meant, it was (IMO) useless to discuss this right from the beginning (not targeted at you, you did not start this).

[Zygonyx]

I don't agree : who knows the exact image circle of DA 645 28-45mm ? It could (schrewdly) be covering 40x54mm, whilst not covering 120/220 DFA / film sensor size.... hence not limited to 33x44mm sensor size...

[OoKU]

I don't agree : who knows the exact image circle of DA 645 28-45mm ? It could (schrewdly) be covering 40x54mm, whilst not covering 120/220 DFA / film sensor size.... hence not limited to 33x44mm sensor size...

The patent show is only cover 33*44