[Winder]

Some actual measurements would be good to know, not to mention what part of the cycle is involved with the image circle, because there has to be movement associated with acceleration and deceleration. Thanks for digging that one out. I'd only looked for information on the Pentax system, and Falk is one of the few people here concerned with objective measurement, rather than vague generalities.

They would be good to know. It maybe possible. It may not be possible. Right now we have a theoretic measurement for what is needed and I guess that will get a us a theoretical camera to use. So far the only real world camera to use SR in a FF body requires a lot more space than the theoretical. I don't use theoretical cameras. Maybe Pentax engineers are much smarter than Sony engineers. I hope that is the case, but so far they haven't proven it.

Given what Pentax has said, and looking at what Sony has done, I am inclined to believe that it is an actual problem regardless of the theoretical. What Pentax has said and Sony's actual product are not "vague generalities".

[RobA_Oz]

They would be good to know. It maybe possible. It may not be possible. Right now we have a theoretic measurement for what is needed and I guess that will get a us a theoretical camera to use. So far the only real world camera to use SR in a FF body requires a lot more space than the theoretical. I don't use theoretical cameras. Maybe Pentax engineers are much smarter than Sony engineers. I hope that is the case, but so far they haven't proven it.

Given what Pentax has said, and looking at what Sony has done, I am inclined to believe that it is an actual problem regardless of the theoretical. What Pentax has said and Sony's actual product are not "vague generalities".

True, and without endlessly debating the theory (as interesting as the engineering side is for some of us, as distinct from the associated polemics), the original question was about the limitation imposed by existing FA lens image circles, not how much room was going to be needed within the body of this theoretical camera to implement SR, which would presumably have to be several stops worth.

[Fogel70]

They would be good to know. It maybe possible. It may not be possible. Right now we have a theoretic measurement for what is needed and I guess that will get a us a theoretical camera to use. So far the only real world camera to use SR in a FF body requires a lot more space than the theoretical. I don't use theoretical cameras. Maybe Pentax engineers are much smarter than Sony engineers. I hope that is the case, but so far they haven't proven it.

Given what Pentax has said, and looking at what Sony has done, I am inclined to believe that it is an actual problem regardless of the theoretical. What Pentax has said and Sony's actual product are not "vague generalities".

So how much is the sensor in Sony FF camera move when in use?

The demo of how much the sensor can move do not tell how much of the movement is used when picture is taken.
As the sensor has to start moving when shutter is closed before the picture is taken and also move after shutter is closed it will not use all movement for shake reduction. And it does not matter if sensor reach outside the image circle before/after picture is taken. Which probably happens on Sony FF cameras when sensor is at its endpoints of movement.

On all Pentax DSLR the sensor also move much more than is in use for SR. And the distance the sensor has to move before picture is taken will vary with focal lengh used, as with the longer focal length the sensor has to move faster, and the faster the sensor move the longer distance it takes to accelerate the sensor to correct speed before picture is taken.

[Winder]

So how much is the sensor in Sony FF camera move when in use?

The demo of how much the sensor can move do not tell how much of the movement is used when picture is taken.
As the sensor has to start moving when shutter is closed before the picture is taken and also move after shutter is closed it will not use all movement for shake reduction. And it does not matter if sensor reach outside the image circle before/after picture is taken. Which probably happens on Sony FF cameras when sensor is at its endpoints of movement.

On all Pentax DSLR the sensor also move much more than is in use for SR. And the distance the sensor has to move before picture is taken will vary with focal lengh used, as with the longer focal length the sensor has to move faster, and the faster the sensor move the longer distance it takes to accelerate the sensor to correct speed before picture is taken.

I agree with what you are saying, but I still want to see the actual size of the image circle projected. Sony A900 IBIS is not as effective as OIS. It might be possible to design a K-1 with IBIS of 1-2 stops. It might be possible to design one with 3-4 stops. It might be possible to design a lot of things.

Pentax is pretty silent on technology they are working on. Most of the time a "No Comment" is all we are going to get if Pentax is working on something. To my knowledge Pentax has never lied to its users about where it was going or what it was working on. They just keep quiet. Coming out and publicly saying that most lenses don't have an image circle large enough to support a FF sensor and IBIS is a very specific statement about a very specific challenge to developing a full frame body. People apparently now think that Pentax has started lying to them about future product development. That is a big change from simply saying nothing.

When JC does an interview and says nothing (which is most interviews) people complain because Pentax "does not communicate".
When JC does an interview and says specifically that this is a problem people refuse to believe him. He is probably better off saying nothing. I am starting to understand why he does not waste his time trying to communicate with the customer base.

MF and the MF lenses are not selling well enough to justify developing OIS specifically for that system. OIS is just not a feature that is really needed for a camera that will spend the majority of its time on a tripod for most users. Pentax shares as much technology as it can across platforms to spread out the cost. It is possible that OIS was developed specifically for a $5,000 lens that will sell a few hundred copies a year, I doubt that is the case. 90mm is not exactly a focal length that really needs image stabilization.

I think it is more likely that Pentax developed the OIS technology to address the problem of putting IBIS in a full frame body.
I think the reason JC was so specific about the challenges of putting IBIS in a FF (the only thing he has ever been specific about) is because it is a real issue that they are working on. There is no reason to be so specific about a problem that does not exist.

On the bright side:
Pentax has developed a new AF system with F/2.8 sensors. This is pretty important for the development of longer, faster glass. It is a good sign.
Pentax has developed new lens coatings. This is a good sign that we might see some lenses updated.
Pentax has developed OIS. This is a good sign. There are some advantages to OIS in regards to future technologies.

Not much reason to spend a lot of money on developing the above technologies unless you plan an bringing some serious glass to the market in the near future.

[RobA_Oz]

I don't see that anybody here was suggesting that Pentax reps were lying about the image circles of existing lenses. There are only five Pentax lenses still in production that are legacies from the film era. Several people here have suggested that older designs could be brought back with minimal redesign to suit a new 35mm sensor body. The extent of such redesign will depend on matters like how much the image circles would have to be increased to incorporate IBIS. Increasing the image circles may be just a question of changing the size of some masking elements in the optical path, or it might mean totally new designs, or somewhere in between.

Curiosity about why and what is healthy, and it's a damn sight more useful in informing people about what is the truth than mere daydreaming. Robust debate is similarly useful, so let's not get sidetracked. You don't have to lie to not reveal the truth.

[Class A]

I think the reason JC was so specific about the challenges of putting IBIS in a FF (the only thing he has ever been specific about) is because it is a real issue that they are working on.

If the engineers had a challenge/problem John Carlson would be one of the last people to know about it. Pentax USA has very little knowledge about technical details.

The evidence collected by forum members clearly contradicts John Carlson's observation. There are a number of DA lenses which will be fully usable on FF and he plainly forgot about the DFA lenses.

There is absolutely no reason to believe that a Pentax FF camera won't have SR.

John Carlson should be worried about the potential damage he is causing with his interviews.

[Winder]

If the engineers had a challenge/problem John Carlson would be one of the last people to know about it. Pentax USA has very little knowledge about technical details.

So what your saying is that JC was lying? He intentionally created a fictitious technical challenge. I don't think JC is much of an independent thinker. I expect that Pentax knows the FF question is going to be asked every time. I think his answers were well prepared. Given how tight lipped Pentax is, I think this statement was intentional and with the new OIS technology on display the statements are indicative of the direction Pentax is headed. I am surprised that none of the interviewers asked if the OIS used on the new 90mm would be employed on future K-mount glass.

The evidence collected by forum members clearly contradicts John Carlson's observation. There are a number of DA lenses which will be fully usable on FF and he plainly forgot about the DFA lenses.

Post a link to the evidence. JC did not forget about any lenses. He was making a general statement about the majority of the lenses they make.

There is absolutely no reason to believe that a Pentax FF camera won't have SR.

You mean other than a direct statement from a Pentax executive?
You mean other than the fact Pentax has designed an new OIS system?
You mean other than the fact that Pentax can make a lot more money with OIS than it can with IBIS?

[vonBaloney]

You mean other than a direct statement from a Pentax executive?
You mean other than the fact Pentax has designed an new OIS system?
You mean other than the fact that Pentax can make a lot more money with OIS than it can with IBIS?

Seems like they need a whole new line-up of glass either way. If IBIS, then they need to have big enough circles, otherwise they will probably come out with optical stabilized lenses. And they will all have the new coatings, etc etc. Even if they just use IBIS and there is some vignetting on older lenses, I don't think that is the end of the world. But they need a major glass overall even if they don't even come out with FF...

[Winder]

Seems like they need a whole new line-up of glass either way. If IBIS, then they need to have big enough circles, otherwise they will probably come out with optical stabilized lenses. And they will all have the new coatings, etc etc. Even if they just use IBIS and there is some vignetting on older lenses, I don't think that is the end of the world. But they need a major glass overall even if they don't even come out with FF...

I agree. Pentax did not roll out any exciting product at the big show, but if you look at the separate technologies that they rolled out, it looks like they have big plans for the up coming year.

1. HD coating. Pretty significant, especially for faster glass.
2. New F/2.8 AF system. Pretty significant, especially for faster glass and available light photographers.
3. New OIS. Did Pentax really invest in this only to use it only on a couple of 645D lenses? Kind of hard to believe.

I think the technology introduced at the show points to some pretty significant lens updates in the near future. Maybe next year will set the stage for a FF system. Either way Pentax has a lot of work to do next year.

[Class A]

So what your saying is that JC was lying?

No, because lying requires intent.

JC often isn't quite on top of things but makes statements nevertheless (e.g., when he claims the K-mount is almost 30 years old (it is older) or the K-30 has the same shutter as the K-5 (it doesn't)). These statements then turn out to be false, but that doesn't mean he is lying. He is just a terribly unreliable source of information.

I think his answers were well prepared.

Why can you catch him making incorrect statements so many times then?

Post a link to the evidence. JC did not forget about any lenses. He was making a general statement about the majority of the lenses they make.

JC said:

It’s a big commitment because while it’s not a different mount, you have to create lenses for that, because all of our current lenses, except for three Limiteds, are designed for the APS-C sensor.

So the three D-FA macro lenses are not currently offered by Pentax? And the FA 50/1.4?
He just forgot about them.

JC also said:

All the tests I’ve seen, if you put those lenses on a film body, you get vignetting.

This contradicts findings by forum users who tested DA lenses on FF cameras. There are at least three so-called APS-C lenses which will work a 100% on FF.

You mean other than a direct statement from a Pentax executive?

Pentax USA does not develop anything. Their only purpose is distribution. JC is a salesman, not to be confused with an executive at Pentax Japan.

You mean other than the fact Pentax has designed an new OIS system?

For the 645 mount and a macro. Maybe the OIS is specifically designed for macro purposes (normal SR is not and is not helpful in macro situations). Maybe there are no 645 in-body SR plans and Pentax still wanted to offer a lens with OIS. In any event, using the fact that there is a 645 OIS lens to conclude that an FF camera won't have in-body SR is jumping to conclusions, AFAIC.

You mean other than the fact that Pentax can make a lot more money with OIS than it can with IBIS?

So why has the K-30 in-body SR? Why not make more money with APS-C lenses as well?

Pentax has to catch up with respect to marketshare. Weather-sealing, in-body SR, and the availability of many used lenses for the K-mount are plus points.

I don't see a Pentax FF camera without in-body SR that is more expensive than competitive models (lower volumes require a higher per piece price) but with worse AF performance and less lens availability to be successful in the market.

A Pentax FF with in-body SR would be the only FF DSLR combining this feature with an optical viewfinder. Not capitalising on this unique selling point would be pure madness.

[RobA_Oz]

Without wanting to re-start the heated discussion in this thread, the following was a relevant post from Falconeye in https://www.pentaxforums.com/forums/pentax-news-rumors/200179-one-more-interv...nglish-8.html# (now closed).

It addresses the question left hanging during the discussion.

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.