[RonHendriks1966]

Sorry Ron, I'd vote for the square over aps-h myself if starting from scratch sensor-wise. Imagine never rotating your camera for a 'portrait' shot ever again; I'd be OK with that! I'd like to think it could be 28-30mm on a side but I haven't done any math on it, just dreaming

This is discussed earlier on the forum. The question on how large can a sensor be when it has a different shape. It's math: a^2 + b^2 = c^2 and the max diameter for k-mount is then compared to the full frame size is 43,27mm

So for:
square sensor this means 30,6 x 30,6 mm at max.
4:5 sensor would mean 33,8 x 27 mm
4:3 sensor would mean 34,6 x 26 mm
And then some options, but these are historic sizes in photography.

[Kunzite]

Maybe we should reframe the question... if Pentax decide they can't support an FF camera, would you go for APS-H as an alternative as an upgrade to the K-* line? Given the choice, A7r type camera from another brand or 24-30 APS-h from Pentax, I'd look at the APS-h as my next upgrade. But really, I'm still looking for that $3500 645D.

I doubt the effort to support an APS-H line is smaller than the one required for "full frame". The sensor could be an issue (Ricoh would have to secure a constant supply of high-quality custom-size sensors; no good if they're worse than APS-C), a new line of lenses would be needed anyway (nope, APS-C lenses that marginally works are not a solution), everything else is pretty much the same.
In other conditions, if the sensor size had a more dramatic effect on cost, an intermediary format would made sense; but this is not what's happening, on the contrary, the cheapest "full frame" are only $200 more than the most expensive APS-C (and that's an old model, long due for replacement). I don't see any room for APS-H, one that would make the effort feasible.

[normhead]

The model I see that would be feasible would be if Pentax FF lenses don't make a big enough image circle to support in Camara shake reduction. Then Pentax is effectively left with the choice of a whole new line of lenses, making FA lenses only work in crop mode, or dumping SR across their whole line.

SO while I agree with you as a general point, I can see where it would come to APS-h in some kind of crop mode on a Pentax FF camera for FA glass when shake reduction is turned on), and a whole new FDA line of lenses for FF with shake reduction.

So I can see at least one scenario where APS-h would live, although not as an APS-h sensor. Many Pentax FF lenses suffer from vignetting covering an FF circle (as do FF lenses from other manufacturers). That is not compatable with in camera SR. The vignetting would be unpredictable and not centred on the middle of the frame, as it often is with the 18-135 on Pentax APS-c.

[RonHendriks1966]

I doubt the effort to support an APS-H line is smaller than the one required for "full frame". The sensor could be an issue (Ricoh would have to secure a constant supply of high-quality custom-size sensors; no good if they're worse than APS-C), a new line of lenses would be needed anyway (nope, APS-C lenses that marginally works are not a solution), everything else is pretty much the same.
In other conditions, if the sensor size had a more dramatic effect on cost, an intermediary format would made sense; but this is not what's happening, on the contrary, the cheapest "full frame" are only $200 more than the most expensive APS-C (and that's an old model, long due for replacement). I don't see any room for APS-H, one that would make the effort feasible.

Well My starting point is that the sensor will be good and better performing then current aps-c sensors. I have no idea why people start to think overhere thet the sensor inside the new Phase One IQ250 50 megapixel cmos sensor would not be of current level of IQ from a pixelsize seen.

On the performance of current lenses there is a nice question. Maybe someone with the Sony A7 and adapter could answer on these. So wich lenses in production today would perform well on aps-h? (and maybe even also on full frame).

The yes: DFA 100mm and 50mm Macro; FA 31mm, 43mm and 77mm; DA*55mm, 200mm and 300mm.
The maybe: DA 35mm, 40mm, 50mm 70mm, 560mm, DA*60-250mm.
The No: DA35mm macro; DA 14mm, 15mm, 21mm, 10-17mm, 12-24mm, 17-70mm, 18-55mm, 18-135mm, 18-270mm, 20-40mm, 50-200mm and 55-300mm; DA*16-50mm and 50-135mm.

So only 6 lenses in the maybe section, while the lenses in the yes section will perform better (les vignet) on the smaller aps-h then on full frame. If a few off the lenses in the maybe section will do better on aps-h then there is point!

[Parry]

Okay, OS full frame lenses from third parties, Sigma and Tamron.

Did a search on the B&H site and selected full frame coverage, optically stabilized and only from Sigma and Tamron. These could all be produced in K-mount if needs be, don't know how many are.

Haven't looked at the list, just going to post the link . . . .

SLR Lenses | B&H Photo Video

[richard balonglong]

Full frame is still better!
Put an APS-H (for even higher burst rate), APS-C (for extra tele reach), and Square crop mode functions with a twist, that's something for Pentax-Ricoh.
Maybe something like:
In Full Frame, the image is equals to 24mp and giving up to 5fps burst rate
In APS-H mode, image is equals to 14mp and giving up to 10fps burst rate (good for fast-phase shooters)
In APS-C mode, image is equals to 16mp and giving 5fps burst rate? (for those tele shooters and using cropped lenses)
In Square mode, image is equals to 18mp with 5fps burst rate (for those who wants squares)
With this kind of options, you can use all FF lenses down to APS-C lenses...
Lol... What do you think?

[RonHendriks1966]

Okay, OS full frame lenses from third parties, Sigma and Tamron.

Did a search on the B&H site and selected full frame coverage, optically stabilized and only from Sigma and Tamron. These could all be produced in K-mount if needs be, don't know how many are.

Haven't looked at the list, just going to post the link . . . .

SLR Lenses | B&H Photo Video

You forgot the full frame, but it is a nice list from Sigma:

120-300mm, 180mm macro, 50-500 (bigma), 70-200, 150mm macro, 120-400mm, 24-105mm, 150-500mm, 105mm macro and 70-300mm lens.

So 10 lenses from Sigma, but not much in the wide-angle to normal.

[Kunzite]

The model I see that would be feasible would be if Pentax FF lenses don't make a big enough image circle to support in Camara shake reduction. Then Pentax is effectively left with the choice of a whole new line of lenses, making FA lenses only work in crop mode, or dumping SR across their whole line.

Why on Earth would they make SR-enabled "full frame" cameras, but not lenses with image circles large enough to cover it? That doesn't make any sense.

And basing such a strategic decision on the supposedly bad performance of some old lenses (which supposedly would perform very well on APS-H) is something that happens only on internet forums. I'd be curious to know why it didn't happen when Sony users were putting old Minolta lenses on their stabilized "full frame" DSLRs... where are their complaints, images with black corners?
Let's not forget one can actually crop the "full frame" image to an arbitrary smaller format, APS-H included.

Well My starting point is that the sensor will be good and better performing then current aps-c sensors. I have no idea why people start to think overhere thet the sensor inside the new Phase One IQ250 50 megapixel cmos sensor would not be of current level of IQ from a pixelsize seen.

"Will be good and better performing"? That's a condition for it to work, not a fact. And I wouldn't stop at one sensor; it will have to be improved, to keep up with the dynamic APS-C market (and this within minuscule volumes).

Lens compatibility is a red herring; first because several of them would either work well on "full frame", or need to be improved anyway. And second, because its limited to the current lens selection. Sony launched their "full frame" E-mount with zero "full frame" lenses, now they have about 3 and a roadmap; Pentax is in a much better condition - yet somehow they shouldn't do it?

[ElJamoquio]

Well there is no way Ricoh can sell a 24 megapixel Full Frame camera as cheap as the Nikon D610 is currently, simply because they lack the cheer number off sales. So offering the same as the competition won't make many people happy. The question how to market it is thus not in a way off price per megapixel, but performance to the sensor as a whole system.

What's the ratio of market share of the K-3 compared to the D7100? The K-3's slightly cheaper.

Their FF needs to be competitive, so they'll either introduce a competitive camera or not introduce anything. Everything they've said over the past 1.5 years is that it's coming.

The APS-H would likely be more expensive as it would be a custom chip...

[Fogel70]

This is discussed earlier on the forum. The question on how large can a sensor be when it has a different shape. It's math: a^2 + b^2 = c^2 and the max diameter for k-mount is then compared to the full frame size is 43,27mm

So for:
square sensor this means 30,6 x 30,6 mm at max.
4:5 sensor would mean 33,8 x 27 mm
4:3 sensor would mean 34,6 x 26 mm
And then some options, but these are historic sizes in photography.

Lens mount diameter is not the max size of the sensor diagonal that can be used. Lens mount size limit the amount of light that can reach the sensor (aperture size). Mount diameter will also limit the size of the mirror in a DSLR,
But on a mirrorless K-mount camera a 645D sized sensor can probably be supported, But as max aperture will be severely limited, there is not much to gain by using a large sensor like that.

37mm screw mount has been used in cameras (Asahiflex) that support 35mm film. But Asahi soon updated to 42mm to support faster lenses.

[ElJamoquio]

Okay, OS full frame lenses from third parties, Sigma and Tamron.

Did a search on the B&H site and selected full frame coverage, optically stabilized and only from Sigma and Tamron. These could all be produced in K-mount if needs be, don't know how many are.

Haven't looked at the list, just going to post the link . . . .

SLR Lenses | B&H Photo Video

Older list, but there's about 40 lenses advertised as full frame and another 6 or so that aren't advertised as such but are fully capable.

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/183420-curr...me-lenses.html

No system is ever introduced with this much support.

[Adam]

The difference between FF and APS-C sensor noise performance isn't huge these days. Why would anyone buy a camera where that difference was even less significant and the cost of yet another crop factor? Modern CPUs are fast enough to handle high-speed shooting with FF sensors

[RonHendriks1966]

What's the ratio of market share of the K-3 compared to the D7100? The K-3's slightly cheaper.

Their FF needs to be competitive, so they'll either introduce a competitive camera or not introduce anything. Everything they've said over the past 1.5 years is that it's coming.

The APS-H would likely be more expensive as it would be a custom chip...

Well I would guess somewhere between 3:1 and 4:1 in favor for the Nikon. For the Nikon 60D/70D it is even more like 6:1 or so.

[ElJamoquio]

Well I would guess somewhere between 3:1 and 4:1 in favor for the Nikon. For the Nikon 60D/70D it is even more like 6:1 or so.

So Nikon has about the same number of APS-C cameras (maybe one more?) as Pentax. They introduce them faster though, or at least it seems that way.

If Pentax introduces a FF, Nikon will have 3 x as many FF bodies on the market.

If the K-3 can be cheaper than the D7100, why can't the Pentax FF only be marginally more expensive than the 'equivalent' Nikon body (the D800?)?

[RonHendriks1966]

So Nikon has about the same number of APS-C cameras (maybe one more?) as Pentax. They introduce them faster though, or at least it seems that way.

If Pentax introduces a FF, Nikon will have 3 x as many FF bodies on the market.

If the K-3 can be cheaper than the D7100, why can't the Pentax FF only be marginally more expensive than the 'equivalent' Nikon body (the D800?)?

Well overhere the K-3 is 1249 euro and the D7100 is 899 euro.

Looking at this graph: http://www.sonyalpharumors.com/2013-sales-sony-nex-5r-is-the-most-sold-mirro...mera-in-japan/


All camera's with aps-c sensor not on it on sale in 2013 have combined a 3,4 % marketshare. Among them are K-5, K-5 II, K-5 IIs, K-50, K-500 and K-3 and models from other brands. Some off them just a short time on sale in 2013.

All camera's with full frame sensor not on the graph and on sale in 2013 have a combined marketshare off 1,3 %. Among them 1Dx, D4, 5D Mk II, D610, Leica and some Sony.