[gazonk]

One of the big advantages of an FF DSLR is the big viewfinder. With an electronic viewfinder on a mirrorless it would be difficult to see much advantage

+1! The IQ of K-5 is already so great that a large, bright OVF could actually be what would tempt me to upgrade to an FF Pentax.

[Clavius]

Fortunately, you are wrong. At most, new lenses would be required - with a slightly larger image circle; but I suspect some of the actual lenses will work with SR.
For SR-incompatible "FF" lenses (but which are they?) a slight cropping would solve such issues. Though my guess is that it's not necessarily the image circle, but the image quality that makes launching a new line of lenses imperative.

What good is FF-format if you end up cropping the images back to APS-H or even APS-C in PP?!?

If FF+SR is not possible in all cases, then it's not possible. What would the userbase do if Pentax releases an FF body with SR, and then let that userbase discover that an X number of FF-labelled glass is not really supported by their new FF body?

A completely new mount will solve that, as only the new lenses with the new mount will work on it. An PK adapter could then enable SR and autocrop for DA lenses only.

[gazonk]

A completely new mount will solve that, as only the new lenses with the new mount will work on it. An PK adapter could then enable SR and autocrop for DA lenses only.

IMHO if you're not going to keep the K-mount anyway, it makes a whole lot more sense to build a lighter, more compact and less expensive 645-mount camera.

[RobA_Oz]

For those who didn't read the post, here again is what Falk said on the subject of in-body stabilisation and a FF K-mount body:

I only computed the necessary amount of sensor shift during the exposure.

It is up to the engineers to be smart or not. AFAIK, Pentax uses 2mm margins, which means the sensor is able to move 10x more than would be required. This is nice for LV or video, but was done at the age of CCD. I think Pentax engineers used this extra space to accelerate the sensor from the start position after you full-press the shutter. However, it is possible to accelerate the sensor in a non-linear fashion such that no extra space is required to lock the sensor. Just a little bit more engineering will and a bit stronger shift motor are required.

I only wanted to say one thing: K mount and SR for full frame don't contradict each other.

There seems to be a tendency for people to adopt a more pessimistic view of the issue than the one person here who has actually done some analysis on the subject. I'm not sure what more can be said.

[Clavius]

For those who didn't read the post, here again is what Falk said on the subject of in-body stabilisation and a FF K-mount body:


There seems to be a tendency for people to adopt a more pessimistic view of the issue than the one person here who has actually done some analysis on the subject. I'm not sure what more can be said.

Here's the picture of the bogus K3 from last years 1st of April:




Now take your K5, take of the lens, stare down the mount and switch on LV. See how much the lens moves. It looks quite cool, as if it's floating.

But it also means that if the FF sensor has to move THAT much, then its corners will disappear behing the lens mount.

Or, just look at Sony's FF camera with SR. Do you think their mount is so big for fun? Bigger mount = more glass = higher prices. I think they would avoided that if it would have been possible. Add to that that Sony's SR doesn't even match Pentax SR.

A new lens mount will not only make SR easier to implement, it will also make a mirrorless FF a lot easier too. LOL!

[Kunzite]

A new mount is not needed, and it won't happen.
And FYI:
- the Minolta AF mount was designed way before AntiShake
- if some old "full frame" lenses don't have a large enough image circle, or are otherwise not performing up to the required standard, the necessary and sufficient solution is to replace it with a newly designed lens. A new, larger diameter mount might help designing such lenses but it's not required.
- having limited compatibility is much better than breaking the compatibility
- if changing the system would be enforced (it won't, of course) for many it would be the needed impulse for jumping ship

[mecrox]

A new mount is not needed, and it won't happen.
And FYI:
- the Minolta AF mount was designed way before AntiShake
- if some old "full frame" lenses don't have a large enough image circle, or are otherwise not performing up to the required standard, the necessary and sufficient solution is to replace it with a newly designed lens. A new, larger diameter mount might help designing such lenses but it's not required.
- having limited compatibility is much better than breaking the compatibility
- if changing the system would be enforced (it won't, of course) for many it would be the needed impulse for jumping ship

The only people who actually know one way or the other are the Pentax engineering team and, at least so far, they aren't saying. All else is guesswork, often highly informed and intelligent but still guesswork I'd have thought. In any case, I can't see this as remotely a big deal. If there is no room for in-body SR on full frame, then put it in the lenses like so many others. Job done. The many thousands of folks who already buy Sigma lenses for Pentax are already doing this and they don't seem to have a problem with it, in general anyway. It's ironic, too, because at the moment it looks as if Pentax may depend quite heavily on third-party outfits with in-lens SR to make up a library of FF lenses come the launch of any FF camera.

The one thing Pentax spokesmen always emphasize is the K-mount and its legacy, the huge inventory of older lenses. If they mess with that (which I don't think they will) they would put their company out of business most likely. Of course, a lot of legacy-lens folks might complain that a new in-lens SR system means they now won't have any SR on their FF Pentax camera but, hey, a small amount of nudging to upgrade to newer models of lens is no bad thing and there's no reason why Pentax has to offer a bit of a free lunch to those hoping to attain full SR when using a 30-year-old 50mm, for example. Besides, no SR on legacy lenses doesn't seem to have hurt Nikon whose trade in older lenses seems always to be booming. As with autofocus, there is life without SR you know.

[maxfield_photo]

There is of course the new 645 90mm macro with lens based SR, maybe we'll see that technology trickle down to the K mount, particularly for very long lenses where in-body SR isn't quite as effective.

[Kunzite]

The only people who actually know one way or the other are the Pentax engineering team and, at least so far, they aren't saying. All else is guesswork, often highly informed and intelligent but still guesswork I'd have thought. In any case, I can't see this as remotely a big deal. If there is no room for in-body SR on full frame, then put it in the lenses like so many others. Job done. The many thousands of folks who already buy Sigma lenses for Pentax are already doing this and they don't seem to have a problem with it, in general anyway. It's ironic, too, because at the moment it looks as if Pentax may depend quite heavily on third-party outfits with in-lens SR to make up a library of FF lenses come the launch of any FF camera.

The one thing Pentax spokesmen always emphasize is the K-mount and its legacy, the huge inventory of older lenses. If they mess with that (which I don't think they will) they would put their company out of business most likely. Of course, a lot of legacy-lens folks might complain that a new in-lens SR system means they now won't have any SR on their FF Pentax camera but, hey, a small amount of nudging to upgrade to newer models of lens is no bad thing and there's no reason why Pentax has to offer a bit of a free lunch to those hoping to attain full SR when using a 30-year-old 50mm, for example. Besides, no SR on legacy lenses doesn't seem to have hurt Nikon whose trade in older lenses seems always to be booming. As with autofocus, there is life without SR you know.

Are you sure everything is just guesswork?
Asahiflex was using an M37 mount, and it was "full frame". If the mount diameter is so critical for the image circle, and it's impossible to make new K-mount lenses with an image circle 2mm larger, how did that Asahiflex work? Was it vignetting heavily but nobody cared?

Since you were talking about Sigma lenses... if you can find one example, which works fine on a "full frame" Sony DSLR/SLT (with stabilization) and it's also offered in K-mount that would prove the K-mount is not a limiting factor

I agree with you, messing with the compatibility would most likely kill them; that's why I'm certain they won't change the mount (not for a very, very good reason - and AFAIK everyone who did it had such a reason). So the first question which MUST be answered is: "can't we solve the issue without changing the mount?"
If only those advocating a mount change would take time to think about that question...

[mecrox]

Are you sure everything is just guesswork?
Asahiflex was using an M37 mount, and it was "full frame". If the mount diameter is so critical for the image circle, and it's impossible to make new K-mount lenses with an image circle 2mm larger, how did that Asahiflex work? Was it vignetting heavily but nobody cared?

Since you were talking about Sigma lenses... if you can find one example, which works fine on a "full frame" Sony DSLR/SLT (with stabilization) and it's also offered in K-mount that would prove the K-mount is not a limiting factor

I agree with you, messing with the compatibility would most likely kill them; that's why I'm certain they won't change the mount (not for a very, very good reason - and AFAIK everyone who did it had such a reason). So the first question which MUST be answered is: "can't we solve the issue without changing the mount?"
If only those advocating a mount change would take time to think about that question...

Unless a statement comes directly from Pentax, then yes it should be treated as guesswork or at least provisional. But if someone wants to spend many thousands of bucks on the basis of a say-so from a bloke on the internet, then who am I to suggest that large, gentle men with white coats and a restraining harness should be summoned first.. It's not only a question of engineering but of cost. There might be a situation, for example, in which though FF IBIS on Pentax is technically achievable this could only be done at a cost the project managers think is unacceptable because it would raise the unit price of each camera far enough to kill sales and profitability. We just don't know. The "cheap bodies and expensive lenses" scenario would actually rather favour in-lens SR over IBIS, if that approach is of appeal to Pentax.

As for Sigma, my guess - yes, a guesstimate - is that they may include some stabilized lenses in their new ART series which sounds tasty, which is FF and which, on the face of it, provides some good quality kit. Or, Pentax might go to them and propose a deal of some kind. I don't see how Pentax on its own can provide a credible library of FF lenses if the plan is to launch a conventional FF DSLR. They need Sigma a lot more than Sigma needs them, at least at the moment. Are you saying that no lenses with in-lens SR currently offered by Sigma will work on an FF Pentax? Possible I suppose but sounds a bit unlikely.

FWIW, another guesstimate, my feeling is that Pentax haven't held off producing FF because of any technical issues. They have held off because an ageing and very conservative management allowed themselves to become obsessed with APS-C DSLRs and they convinced themselves this was the only way, the very future of the universe depended on it. With luck, the arrival of new owners as begun to change that.

[Kunzite]

If we're talking about cost/effort, indeed we can only guess; but was Clavius talking about cost or effort? Unless invisible ink was used, he simply claimed it's not possible
And people like us, who aren't Pentax engineers, can prove if the K-mount would accommodate a lens with a large enough image circle, for an in-camera stabilization system. Everything else is up to Pentax.
By the way, I'm not claiming that people should act based on my, or Clavius' words. Not every possible thing happens, and some impossible things actually are not that difficult.

No, I'm not saying that Sigma lenses with in-lens stabilization won't work on a Pentax FF (and please don't try to put words I never said in my mouth); on the contrary, they should work just like on an APS-C DSLR.
Pentax seems able to launch about 4 K-mount lenses per year, if needed they probably could make an extra effort. I'd say they can handle it.

[RonHendriks1966]

Now take your K5, take of the lens, stare down the mount and switch on LV. See how much the lens moves. It looks quite cool, as if it's floating.

But it also means that if the FF sensor has to move THAT much, then its corners will disappear behing the lens mount.

Or, just look at Sony's FF camera with SR. Do you think their mount is so big for fun? Bigger mount = more glass = higher prices. I think they would avoided that if it would have been possible. Add to that that Sony's SR doesn't even match Pentax SR.

A new lens mount will not only make SR easier to implement, it will also make a mirrorless FF a lot easier too. LOL!

If we're talking about cost/effort, indeed we can only guess; but was Clavius talking about cost or effort? Unless invisible ink was used, he simply claimed it's not possible
And people like us, who aren't Pentax engineers, can prove if the K-mount would accommodate a lens with a large enough image circle, for an in-camera stabilization system. Everything else is up to Pentax.
By the way, I'm not claiming that people should act based on my, or Clavius' words. Not every possible thing happens, and some impossible things actually are not that difficult.

Every few months I do see an oppertunity to drop the APS-H option to get out off this mess!

[Kunzite]

And what problem is this APS-H supposed to solve? New lenses would be required, anyway.

[RonHendriks1966]

And what problem is this APS-H supposed to solve? New lenses would be required, anyway.

Depending on the size off the sensor, more lenses (DA-primes and old lenses) would perform better on that sensor then on a FF sensor. Less stressing on cornerperformance due to the smaller sensor. No issues with the performance off the sensor with SR on the K-mount with lenses since there is more room for sensorbased SR moevement.

(and then some other advantages, but just to stay on this topic).

[Kunzite]

All of these can be "fixed" by cropping, with the option of not cropping for lenses that can cope with the larger format.
For a theoretical lens which would adequately cover just those 24x36mm (and not a mm more), such a crop would be larger than APS-H (assuming SR would need about 2mm of space or so).
Sorry, but I have to be against the APS-H idea, which in itself is not that bad but have a significant drawback: it doesn't solve the lack of a "full frame" issue