[monochrome]

Well, thinking about it the shorter registration distance could make the difference, all other things being equal, since with the same last-element-to-sensor distance, the last element would be nearer to the mount, thus minimizing vignetting.
I don't know much about lens design, but the different registration distance could work to Pentax's advantage, as Na Horul says.

Regarding the argument that "IBIS must be working correctly because Pentax is selling the camera", well, that's a fallacy, and I don't trust a company, any company, that much.
I sincerely hope it's working as advertised, but - just to be the devil's advocate for once - they could have solved the hypothetical issue with a lens profile and be done with it.

If so, the K-1 Special Site wouldn't be a very good idea from a corporate liability standpoint.

Challenges - 3: Downsizing

[Cynog Ap Brychan]

We should not forget, also, that IBIS gives us pixel shift, anti-alias filter simulation and astrotracing. Put that in your pipe and smoke it, Fuji!

[LensBeginner]

If so, the K-1 Special Site wouldn't be a very good idea from a corporate liability standpoint.

Challenges - 3: Downsizing

That depends on the concept of "good enough".
A certain degree of vignetting could be considered low enough not to be relevant by some and a serious issue by others.

[monochrome]

That depends on the concept of "good enough".
A certain degree of vignetting could be considered low enough not to be relevant by some and a serious issue by others.

Theoretically, a certain amount of noise at ISO 50 might not be good enough for some. Everything is conditional on the user.

I really don't understand where you are coming from. The issue the article describes is dependent on the register distance, not the mount diameter. The article writer is ill-informed. A short register distance designed for APSc or m4/3 is a challenge to adapt to FF image circle and also implement IBIS, but that isn't an issue for Pentax. K-mount has always been a FF mount with an APSc sensor behind it. In a sense K-mount is incorrect for APSc, not the other way around.

K-mount is a long mount. It has a deep register distance - 45.46mm - which makes MILC cameras ungainly (as shown by the K-01) So AFA native K-mount lenses are concerned, there won't be any worse vignette with a film-era lens than there was on a film camera just due to IBIS, and all the Pentax lenses save the new zooms are film-era lens designs.

If a K or M or A or F or FA lens vignettes unacceptably, well, them's the breaks - the lenses are decades old.

[Zygonyx]

I can't wait beeing able to actually see what really happens with those legacy lenses.
One very simple measure - if too much vignetting appears due to SR in certain conditions - will simply be to shut SR of

[Fogel70]

I can't wait beeing able to actually see what really happens with those legacy lenses.
One very simple measure - if too much vignetting appears due to SR in certain conditions - will simply be to shut SR of

It if it going to be a major difference in vignetting using SR, then you probably will notice even worse problems turning off SR.
And it's much easier to remove vignetting, than removing camera shake blur.

The sensor is not moving enough for vignetting to be a major problem, unless of course there is a major problem already without SR.

[interested_observer]

We should not forget, also, that IBIS gives us pixel shift, anti-alias filter simulation and astrotracing. Put that in your pipe and smoke it, Fuji!

.... don't forget about Composition Adjustment/Sensor Shift

[slip]

If Pentax didn't have in body stabilization, I would not be a Pentax owner!

[jatrax]

they could have solved the hypothetical issue with a lens profile and be done with it.

Not with legacy lenses. At least with older ones that have no chips.

I used to take issue with people who insisted that "companies cannot be trusted", naively believing that most companies / people at least try to be honest. But after the Volkswagen debacle I no longer dispute that.
However, in this case I will trust Pentax to have delivered a product that lives up to their claims, I think they have too much riding on this to not deliver. YMMV.

[From1980]

I think they have too much riding on this to not deliver.

Agreed, Ricoh/Pentax reputation is riding on this much more than any other recent product.

[Rondec]

At this point, all is speculation -- particularly about older lenses, but certainly at the worst, this will require a little bit of cropping or brightening of the corners in certain situations. It is seldom that a little vignetting makes or breaks a photo. If the corners are dark enough to be not recoverable, then you could test to see if the SR is making the situation worse. I doubt the difference will be significant.

I do think there are sour grapes on Fuji's part. They have an APS-C only camera system. How well that sells in a few years when full frame prices are well below a thousand dollars is hard to say. Certainly APS-C will be here for awhile, but Fuji wants to sell professional cameras with high prices and it might be tough to do down the road.

[pathdoc]

I do think there are sour grapes on Fuji's part. They have an APS-C only camera system. How well that sells in a few years when full frame prices are well below a thousand dollars is hard to say.

Hypothesis: I suspect they looked at the K-1's launch price and their hearts sort of sank into their boots. Up until now, new-launch flagship FF DSLRs have always been significantly more expensive than crops, and that could be their niche. The prospect of a full-frame DSLR that's in upper-level APS-C price territory must be scary when you've hung your hat on the crop sensor.

ETA: I'm not rubbishing APS-C here; I fully agree there's a preferred place for it in some photographers' armamentaria. What I am saying is that it a competitive market, diversification is life - and Pentax has just hammered another lifesaving piton into the sheer cliff of camera sales. Of necessity, true, but it's done.

[Na Horuk]

Hypothesis: I suspect they looked at the K-1's launch price and their hearts sort of sank into their boots. Up until now, new-launch flagship FF DSLRs have always been significantly more expensive than crops, and that could be their niche.

Yep. Fuji had some great gear, but slightly on the expensive side. With prices of FF DSLR, packed with awesome features like the K-1,.. it will be more difficult for them to compete. Its just difficult to justify an expensive APSC system when you can get more affordable APSC system from Pentax, and now possibly even a more affordable FF system.

Fuji is well-liked, but it might become even more of a niche than it already is

[LensBeginner]

Theoretically, a certain amount of noise at ISO 50 might not be good enough for some. Everything is conditional on the user.

I really don't understand where you are coming from. The issue the article describes is dependent on the register distance, not the mount diameter. The article writer is ill-informed. A short register distance designed for APSc or m4/3 is a challenge to adapt to FF image circle and also implement IBIS, but that isn't an issue for Pentax. K-mount has always been a FF mount with an APSc sensor behind it. In a sense K-mount is incorrect for APSc, not the other way around.

K-mount is a long mount. It has a deep register distance - 45.46mm - which makes MILC cameras ungainly (as shown by the K-01) So AFA native K-mount lenses are concerned, there won't be any worse vignette with a film-era lens than there was on a film camera just due to IBIS, and all the Pentax lenses save the new zooms are film-era lens designs.

If a K or M or A or F or FA lens vignettes unacceptably, well, them's the breaks - the lenses are decades old.

Relieved to hear that!
Was just wondering if "designed for FF" with or without SR made much difference.

[Adam]

The K-mount has always been an FF mount. I'm pretty sure that if in-body stabilization had been unrealistic, Pentax wouldn't have gone with it. Only practical tests will tell the whole story, so it will be interesting to stress test the 15-30mm and see if the SR can produce provoke additional vignetting or dark edges of significance. When I played with composition adjustment briefly with that lens, the coverage seemed pretty good.

Nevertheless, the fact K-1 gets in-body "peripheral illumination correction" function would testify some need to conpensate against vignetting, not only when using DA lenses.

Not sure if there's any connection there, since that feature has been around for years in other DSLRs.