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03-08-2012, 08:21 PM - 1 Like   #376
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QuoteOriginally posted by Clavius Quote
With all the negativity on this forum nowadays, it's very easy for me to be the most optimistic person around.

I see multiple advantages:

1. A square 35x35 sensor would be very different. No other brand has that. It could be the niche that Pentax needs. (Or at least: which they say they need.)

2. It would give the missing upgrade path to every Pentaxian. Not only the ones that already have FF glass, or enough money to invest in FF glass.

3. It would buy Pentax some more time. In which they can engineer their FF maybe. Or work out some other brilliant plan.

4. I'm (clearly) not an engineer, but it could maybe fit into a K5 or K20D body?
QuoteOriginally posted by Clavius Quote
My apologies! My enthusiasm got the worst of me. I meant a 30x30 sensor of course. I think all this talk about FF and 35mm got me got me confused.
QuoteOriginally posted by gazonk Quote
Ok, but even with 30x30 you still need the same (*) image circle as for 24x36!

(*) in order to avoid nit picking: You can do with 0.84mm (diameter) smaller circle
What seems to be lost in translation in this thought process is that the biggest square sensor you could use with the current register and mirror box limitations of the K-mount would be 24 x 24. Anything taller than 24mm wouldn't clear the mirror. IOW, not possible unless it's a non-SLR camera with a crappy EVF. Sorry to wake you from your fantasies.

03-09-2012, 02:45 AM   #377
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But even 24x24 is too large for the DA image circle anyway. A square sensor would have to be 20x20.

We can talk about square sensors in full frame mirrorless cameras (as they are the only species where this would make sense) *after* they emerged...
03-09-2012, 06:14 AM   #378
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QuoteOriginally posted by falconeye Quote
But even 24x24 is too large for the DA image circle anyway. A square sensor would have to be 20x20.
My guess too, when all DA lenses have to be used. It would be different when this square, or 5:4 or 4:3 sensor would be the FF answer. Then the sensor can be bigger, making al wide-angle DA lenses unusable for this format.
03-09-2012, 06:48 AM   #379
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a 24 x 24 on a FF makes no sense, just have an auto crop mode that masks the screen and produces a square image (or 5:4, or 4:3 or 16:9 )
then you have the alternates in one body.
6x6 Square MF sensors make sense because a 4:3 crop is a FF 645 frame, you could still have an auto crop but a portrait and a landscape mode option (or just crop it in post).
that sensor of course would be obscenely expensive at this point

03-09-2012, 10:14 AM   #380
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square sensor

QuoteOriginally posted by RonHendriks1966 Quote
My guess too, when all DA lenses have to be used. It would be different when this square, or 5:4 or 4:3 sensor would be the FF answer. Then the sensor can be bigger, making al wide-angle DA lenses unusable for this format.
What I don't understand is: why not have a 30x30 square sensor (which supports any glass made for FF or which works on FF without being made for it), and let the user select the aspect ratio? Everything from square, to 16:9 landscape, to 16:9 portrait, by way of 3:2, 4:3, and 5:4 -- this seems a natural level up from the adjustable aspect ratios of the Panasonic GH line and the auto-cropping of the Nikons. True, this adds no value for DA 15, DA 21, and DA 12-24 users who would only be able to take advantage of the sensor if custom crop modes were included in the firmware. But so much Pentax glass is full frame-capable, so wouldn't this be a unique way to take advantage?
03-09-2012, 10:42 AM   #381
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QuoteOriginally posted by Impartial Quote
What I don't understand is: why not have a 30x30 square sensor (which supports any glass made for FF or which works on FF without being made for it), and let the user select the aspect ratio? Everything from square, to 16:9 landscape, to 16:9 portrait, by way of 3:2, 4:3, and 5:4 -- this seems a natural level up from the adjustable aspect ratios of the Panasonic GH line and the auto-cropping of the Nikons. True, this adds no value for DA 15, DA 21, and DA 12-24 users who would only be able to take advantage of the sensor if custom crop modes were included in the firmware. But so much Pentax glass is full frame-capable, so wouldn't this be a unique way to take advantage?
The mirror would extend another 3 mm 'down' or 'out' from FF. I don't know if there's clearance for such a mirror but others on this thread have indicated there is not.
03-09-2012, 10:47 AM   #382
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QuoteOriginally posted by Impartial Quote
What I don't understand is: why not have a 30x30 square sensor (which supports any glass made for FF or which works on FF without being made for it), and let the user select the aspect ratio? Everything from square, to 16:9 landscape, to 16:9 portrait, by way of 3:2, 4:3, and 5:4 -- this seems a natural level up from the adjustable aspect ratios of the Panasonic GH line and the auto-cropping of the Nikons. True, this adds no value for DA 15, DA 21, and DA 12-24 users who would only be able to take advantage of the sensor if custom crop modes were included in the firmware. But so much Pentax glass is full frame-capable, so wouldn't this be a unique way to take advantage?
Part of the issue is the extra real estate would drive up the sensor cost and it may well be exponentially higher as getting the pieces from a sheet may actually waste more (someone who knows the #'s like falk could probably estimate it). Add in it would be a custom Fab so unless you are ordering (and selling) in Nikon qty it will go up another order of magnitude
A FF sensor could still have the crop modes for the various formats and the smallest it would get is the square 24 x 24 (aside from an apsc crop for DA type lenses)
As for the lenses the FF "capable" DA lenses would be a lot less capable with more pronounced corner softness and vignetting on a square sensor
Even some of the FF lenses would suffer on this

A 24 x 24 sensor would be more cost effective not requiring stitching like a ff sensor and giving a boost over apsc in some format options like 4:3 and 5:4 and of course 1:! (classic apsc would remain much the same though)only issue is you are back to custom fabs and unless you can buy the huge qty you will pay more than you probably would for a 24mp FF sensor that is already in production
03-09-2012, 10:48 AM   #383
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QuoteOriginally posted by ElJamoquio Quote
The mirror would extend another 3 mm 'down' or 'out' from FF. I don't know if there's clearance for such a mirror but others on this thread have indicated there is not.
there is that as well. though as a mirrorless option it hold possibilities

03-09-2012, 11:15 AM   #384
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QuoteOriginally posted by eddie1960 Quote
Part of the issue is the extra real estate would drive up the sensor cost and it may well be exponentially higher as getting the pieces from a sheet may actually waste more (someone who knows the #'s like falk could probably estimate it). Add in it would be a custom Fab so unless you are ordering (and selling) in Nikon qty it will go up another order of magnitude
A FF sensor could still have the crop modes for the various formats and the smallest it would get is the square 24 x 24 (aside from an apsc crop for DA type lenses)
As for the lenses the FF "capable" DA lenses would be a lot less capable with more pronounced corner softness and vignetting on a square sensor
Even some of the FF lenses would suffer on this
I understand the whole "custom fab" issue, my question is more a matter of "why isn't this direction being explored? And alright, there is the mirrorbox issue for DSLR but not for mirrorless . . .

But what I really don't understand is the corner softness/vignetting issue. Isn't it exactly the same issue as in "Full Frame"? That is, aren't all points on the circumference of the image circle essentially the same for these properties?
03-09-2012, 11:44 AM   #385
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The Do-it-all-sensor

Well when I look at all the questions, from 1:1 up to 16:9 and all formats inbetween. For all larger sensors there is a need for new FF lenses, since all wide-angle DA lenses won't do the trick on those bigger sensors.

So what sensor should be in it?
  • 36x24mm for traditional 3:2
  • 30,6x30,6mm for square 1:1
  • 33,75x27mm for your 5:4
  • 34,6x25,95mm for 4:3
  • 37,6x21,15 for 16:9
  • 39,68x16,74 for widescreenHD (2560x1080)
  • 38,912x19,456mm for 2:1 (and 4K video)

Well then a mirrorless (since you see the pixels you use in your EVF or backscreen) with a sensor of 39,68 x 30,6 mm would give all the options you need. Cut from the K-5 wafer, a very large sensor with 53,8 megapixel.

If it only wasn't so expensive
03-09-2012, 01:42 PM   #386
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Put me down for square 1x1! I like the possibilities with a square sensor. I doubt Pentax will stray from 3x2 though.
03-09-2012, 02:10 PM   #387
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QuoteOriginally posted by Impartial Quote
why isn't this direction being explored?
Because it is plain nonsense.

Only if sensor cost is marginalized (and mirror is out) would this make any sense. Otherwise, it is a waste of sensor surface. Images aren't square (most of them) and the ability to turn the camera by 90° maximizes use of the sensor surface. 3:2 does it better than 4:3 or 5:4 (or 1:1) btw.
03-09-2012, 06:26 PM   #388
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QuoteOriginally posted by falconeye Quote
Because it is plain nonsense.

Only if sensor cost is marginalized (and mirror is out) would this make any sense. Otherwise, it is a waste of sensor surface. Images aren't square (most of them) and the ability to turn the camera by 90° maximizes use of the sensor surface. 3:2 does it better than 4:3 or 5:4 (or 1:1) btw.
never mind if i want a square format shot with the advent of ff sensors that are 36 mp i can just crop to square and still have loads of res for printing

If it could be done efficiently then Hassy would have already done it they have a long history of square format and a ton of cameras out there they could sell square sensor back into


I like a square format on film. much easier to shoot a square image with an eye to a crop than to try shooting a WL finder rotated 90 degrees
03-10-2012, 05:06 AM   #389
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QuoteOriginally posted by eddie1960 Quote
If it could be done efficiently then Hassy would have already done it
Maybe I should make myself clear. No reason to argue by analogy.

A square sensor does make sense if the image circle is fully contained on the sensor, i.e., if the sensor width equals the image circle. This is 43.3x43.3mm^2 ! Only possible with mirrorless because as has being said of the required mirror clearance. This sensor has 1872 mm^2 surface!

This is 29% more surface than the sensor in the 645D has (and 117% more surface than 24x36). Clearly not an option as long as sensor surface is a cost factor, and requires mirrorless. But if sensor surface isn't a cost factor anymore, then we'll see lens modules with embedded sensor (such like the GXR modules).

So, such a square 43.3mm sensor (~5x the surface of APSC) will come at some point in the future and will allow to shoot (with FF glass):
39.8 x 16.9 mm^2 (cinemascope 2.35:1)
37.7 x 21.2 mm^2 (HD 16:9)
36.0 x 24.0 mm^2 (photo 3:2)
34.6 x 26.0 mm^2 (compact & MF 4:3)
30.6 x 30.6 mm^2 (square)
26.0 x 34.6 mm^2 (compact & MF portrait 3:4)
24.0 x 36.0 mm^2 (photo portrait 2:3)
(So, if cinemascope if the widest which is ever shot, the 43mm square sensor may actually become 36x40mm^2 which is still the surface of the 645D sensor.)

BTW, the cinemascope mode would make a 12.0mm FF lens usable as a 10.9mm movie lens. This is a case for a 24x40mm sensor rather than a square sensor actually

Sensor cost is already almost no factor in P&S cameras which is why we see the 16:9 to 4:3 variable image formats never reaching the sensor corner. Even the Nokia 808 does this with its huge (for a P&S) sensor.

However, as long as sensor cost is a factor, the sensor should be fully contained within the image circle, i.e., the sensor diagonal equals the image circle.

And with a FF glass circle, this allows for the following sensor formats:
30.6 x 30.6 mm^2 (-> 20.4 x 30.6 or crop 1.18 for 3:2)
34.6 x 26.0 mm^2 (-> 23.1 x 34.6 or crop 1.04 for 3:2)
36.0 x 24.0 mm^2 (-> 24.0 x 36.0 or crop 1.00 for 3:2)

So, with sensor cost playing a rôle, a 3:2 sensor is the best option for most situations.

If increasing the sensor, it is better invested into a linear scale than a square sensor with lots of cropped area in most of the images.

With sensor cost playing no rôle, a lens-module based camera would be best and then, a 43mm square sensor may be used for FF optics.

Last edited by falconeye; 03-10-2012 at 05:17 AM.
03-10-2012, 08:41 AM   #390
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QuoteOriginally posted by ducdao Quote
Here comes another FF thread with 2 gazillions posts
LOoks like you weren't wrong
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