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02-15-2009, 07:13 PM   #46
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QuoteOriginally posted by ogl Quote
Some of DA and DA*lenses can't cover 23.5*23.5 mm sensor.
For example, DA14 can cover only 23.5*18.6 mm, DA*16-50 just a bit more.
Some zooms can cover APS-H, some can not.

Square sensor is only for FF lenses and several DA.
Aren't lenses round? If it can cover 23.5mm on one edge, shouldn't it be able to cover 23.5 on the other edge too? I'm no expert here, but it's what makes sense to me

02-15-2009, 07:30 PM   #47
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QuoteOriginally posted by jay Quote
We should all get together and design a 50 MP full-frame sensor with back-illumination and fluorite microlenses and set up a 450mm wafer size fab process and just make our own damn cameras :-)

We could pull it off. Right?

RIGHT?
Yup. But instead of making a new camera, let's put that sensor in the back of my K2.
02-15-2009, 07:40 PM   #48
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QuoteOriginally posted by soccerjoe5 Quote
Aren't lenses round? If it can cover 23.5mm on one edge, shouldn't it be able to cover 23.5 on the other edge too? I'm no expert here, but it's what makes sense to me
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/31629-da-lens-...ts-thread.html

take DA14 and 16-50's pictures from film here and calculate in Photoshop the size of covering


02-15-2009, 08:50 PM   #49
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QuoteOriginally posted by soccerjoe5 Quote
Aren't lenses round? If it can cover 23.5mm on one edge, shouldn't it be able to cover 23.5 on the other edge too? I'm no expert here, but it's what makes sense to me
No, because the diagonal of a square 23.5 x 23.5 is longer than the diagonal of an APS-C.

Draw a circle.

Draw a rectangle inscribed in the circle.



Now, draw a SQUARE whose width and height are the same size as the WIDTH of that rectangle.

Notice that it doesn't fit into that circle; the corners extend beyond the circle.

That circle is the image the lens casts. The rectangle is APS-C. A lens, currently, ONLY needs to cover that area (obviously, there are lenses that cover more than that area, but that's the minimum area).

That's why you can't have a square format without actually REDUCING the width, to fit inside that square.

And, as I've mentioned, even if they DO shrink the width so the WHOLE square fits inside the circle, that's not the only problem they'd have to worry about:

QuoteOriginally posted by jay Quote
Compounding the problem for the wide-angle lenses is the petal-style lens hoods with which most are equipped. These are NOT symmetric devices; they reduce flare from the top of the lens at the expense of vignetting the top and bottom of the frame, and most would consider them fairly necessary for outdoors shooting.
That's why it's so unlikely they'll do this (along with the more technical discussion about filling these sensors on a wafer, production yield, etc...)

That's why, right now, it seems unlikely they'll change the sensor dimensions at all.

02-15-2009, 09:07 PM   #50
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Wasn't the square format more of a medium format thing? It would be odd if the 645D were released as a 6X6 or 66D....
02-15-2009, 09:34 PM   #51
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QuoteOriginally posted by HawaiianOnline Quote
Wasn't the square format more of a medium format thing? It would be odd if the 645D were released as a 6X6 or 66D....
Yes, it is. And digital medium format -- unless it's some outrageous full-frame design used for -- i don't know? 600 dpi billboards -- isn't going to happen from Pentax.

I have a basic Mamiya 645 system with a few lenses -- I doubt you'd be able to tell the difference between that and a full-frame Canon 5D or 1Ds Mk whatever-they're-up-to.

Pentax predicted that digital 35mm SLR technology was going to get so good, people wouldn't need medium format.

Hasselblad is still betting on it -- but they're not doing so hot these days.

One thing I see people forget a lot when discussing rumors is what's best for the COMPANY -- which is (probably) not what you or I are most interested in.

I want a full-frame body that has a crop mode that offers higher burst rate. To me, it makes sense. If I need a wide view, or lots of pixels, go full-frame, and be forced to use one of my FF lenses. Otherwise, keep it on a low-rez crop format, for extended telephoto reach. I want better AF, and more advanced wireless flash support. I want a Tokina 11-16/2.8 with a Pentax badge on it.

However, that doesn't mean these are things Pentax SHOULD do. Honestly, at some point, as we change as photographers, we need to re-evaluate what our needs are, if they've changed, and if our gear/system provides for it.


...so if I start shooting for 600 DPI billboards, maybe I'll sell my car and buy a Hassy.
02-15-2009, 09:36 PM   #52
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QuoteOriginally posted by jay Quote
0.08 - 0.2 defects / cm^2 is a rough estimate for common chip manufactures, and what we usually run calculations with in my classes -- but as an undergrad, we haven't focused a lot on specific processes and variations in it, and I'm not sure how much that number has changed since our course text was written.

If it were 0.08 defects / cm^2, we're looking at roughly a 32% chance a particular chip is going to have "a defect" (whatever defect that may be)

Some defects may cause hot/dead pixels -- some may cause other problems. And I'm not familiar with their policies on hot/dead pixels. I'm assuming only a small percentage of those defects would cause more than a dead pixel, so yield is probably fairly high compared to logic circuitry (where you simply can't have defects).

I'll look into this and get back to you with some numbers comparing the various chip sizes -- including their yield per wafer (after factoring in defects). I'll try to run it with a few different tolerances on dead pixels.

Haha, if Pentax won't tell us what they're going to do, we'll just do the research ourselves.

We should all get together and design a 50 MP full-frame sensor with back-illumination and fluorite microlenses and set up a 450mm wafer size fab process and just make our own damn cameras :-)

We could pull it off. Right?

RIGHT?
If I remember correctly, most sensors are produced on "old lines" so costs are considerably decreased (due to the lines already paid for). There is little use of new fab lines (these chips are not that complicated) and at the startup costs, it will be unlikely that they will be produced here. China was buying all the old fab equip. at bargain basement prices not too long ago.....
A 2.5bil plant needs a heck of a lot of ROI......
just for fun..
IBM 300mm CMOS Fab, East Fishkill, NY - Global Semiconductor Forum
http://www.dalsa.com/corp/markets/CCD_vs_CMOS.aspx
http://www.fabtech.org/news/_a/smic_in_pilot_production_with_110nm_cmos_imag...or_technology/
http://www.fabtech.org/editor_s_blog/_a/the_us10_billion_bucket/
http://www.fabtech.org/news/_a/intel_to_spend_us7_billion_on_32nm_ramp/

Last edited by jeffkrol; 02-15-2009 at 09:56 PM.
02-15-2009, 09:46 PM   #53
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QuoteOriginally posted by jeffkrol Quote
If I remember correctly, most sensors are produced on "old lines" so costs are considerably decreased (due to the lines already paid for). There is little use of new fab lines (these chips are not that complicated) and at the startup costs, it will be unlikely that they will be produced here. China was buying all the old fab equip. at bargain basement prices not too long ago.....
A 2.5bil plant needs a heck of a lot of ROI......
IBM 300mm CMOS Fab, East Fishkill, NY - Global Semiconductor Forum
CMOS imaging sensors are relatively large chips. I'm assuming they'd use the (now fairly standard) 300mm fab process to increase throughput (in the long run, it's cheaper to use bigger wafers with more chips on each wafer); especially a big firm like Samsung (who makes more sand dollars than IBM).

But, I'm purely speculating.

We need to slap the Wikipedia "This article requires the attention of an expert." notice on this thread.

02-15-2009, 10:43 PM   #54
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Few weeks ago, I was in Tokyo, and went to Yodobashi Camera, one of the largest electronics discount retailers in Japan, and their Pentax guy told me that the company actually considered going with a circular sensor, but scrapped it because of the cost involved in manufacturing it. Don't know too much about any of this, but does this make sense to you guys?
02-15-2009, 11:33 PM   #55
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I copy and pasted the frame size comparison from wikipedia onto a photo ogl uploaded to get an idea of the vignetting issue http://upload.wikimedia.org/wikipedia/commons/9/95/SensorSizes.svg
here's what I got


It's not exactly scientific, and I'm not sure if we're supposed to be looking at the inside or outside of the line, but I don't see vignetting being much of an issue.

Also aren't all the DA*'s APS-H format already. Sure they're not cheap but they're relatively inexpensive compared to most quality lenses out there.
02-15-2009, 11:43 PM   #56
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Here's how the lenses would perform on a square 23.5mm x 23.5mm sensor.
Attached Images
   
02-16-2009, 12:11 AM   #57
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Well, I do hope the rumor becomes true, even if it's unlikely. I'd love to have a camera like that. It'd sure be INTERESTING.
02-16-2009, 02:09 AM   #58
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Original Poster
I just had a look at my favourite photography site in Spanish, and found this:

DSLR Magazine - Sensores cuadrados?

"Sensores cuadrados?

Un artículo de Editor
domingo, 15 febrero 2009

Se han iniciado, simultáneamente, rumores acerca de dos nuevos modelos de cámara con sensores cuadrados. Uno de ellos sería Nikon y otro Pentax/Samsung. ¿La gama?. Alta."

Translation:

"Square sensors?
An article from Editor
Sunday, February 15, 2009

Rumours about two new camera models with square sensors have been started simultaneously. One of them would be Nikon and another Pentax/Samsung. The range? High."

Despite being a very short comment, the fact that his has been published by DSLR Magazine means a lot IMO. This site is extremely serious and very highly reputed for connoisseurs in Spain. (Furthermore, it is run by Valentín Sama, who had several important scoops in recent years). Although one has to admit that it is labeled "rumour".

We will see.

Last edited by cateto; 02-16-2009 at 04:23 AM.
02-16-2009, 04:44 AM   #59
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QuoteOriginally posted by jay Quote
We should all get together and design a 50 MP full-frame sensor with back-illumination and fluorite microlenses and set up a 450mm wafer size fab process and just make our own damn cameras :-)
Propose this as seminar work to your professor. Tell him you expected this level of leading edge research work when signing in at his university.
02-16-2009, 05:21 AM   #60
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Oh dear, this entire thread is a good exercise how an idea, born out of wishful thinking of some guy, and posted at dpr, first becomes rumor and then becomes cited as "news" all over the web. And back-referenced by the original posters as added credential. Very funny!

As for the sensor sizes:
  • FF: 36 x 24 mm, diameter 43.3 mm (crop 1.00) , surface 864 mm^2 (100%)
  • APS-H (Canon 1Dmk3): 28.7 x 18.7 mm, diameter 34.3 mm (crop 1.26) , surface 537 mm^2 (62%)
  • LARGE STUPID SQUARE: 24.25 x 24.25 mm, diameter 34.3 mm (crop 1.26) , surface 588 mm^2 (68%)
  • STUPID SQUARE: 23.5 x 23.5 mm, diameter 33.2 mm (crop 1.30) , surface 552mm^2 (64%)
  • APS-C (K10D): 23.5 x 15.7 mm, diameter 28.3 mm (crop 1.53) , surface 369 mm^2 (43%)

So, the STUPID SQUARE format is more expensive to produce than APS-H (more surface), still having a larger crop factor (narrower FoV with lenses having a larger than APS-C image circle), and most of all, still can only produce images 82% as wide as APS-H.

The LARGE STUPID SQUARE (identical crop factor to APS-H) is even more expensive to produce and still only 84% as wide.


Discussion here already concluded that a square (or octogon) sensor makes sense only if CMOS cost has become marginal when compared against lens cost. Which will happen some day. After FF sensors became commonplace, not before.


Is this enough to stop the APS-H square sensor bullshit rumor? Of course, not

Last edited by falconeye; 02-16-2009 at 05:26 AM.
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