Already "not found" I think is the confirmation that it was an April
Fool's joke. The article proposed an EVIL camera like micro 4/3 but
with a circular sensor whose diameter was the diagonal of a 35mm frame
or 43mm. With adapters it would support all 35mm lenses ever produced
plus more. With a round sensor, cropping could choose any aspect ratio
or even keep it round.
All silicon wafer stock is grown from crystals and produce a long
cylinder which is then sliced into thin wafers for processing. In the
early days (late 60s or early 70s) the crystal cylinders were not far
from 43mm in diameter. Today the cylinders are 12 inches or more in
diameter. Much smaller rectangular chips are laid out in a matrix, cut
out with a saw and the semi-circular bits left at the edges are
discarded. A circular wafer cut from a small diameter cylinder wouldn't
have any edge waste but would be too expensive to process. It would
take the efficiency level back some 40 years. Those 12 inch wafers were
developed for a reason. IIRC is has to do with the efficiency of the
manufacturing process as well as the areal distribution of defects which
affects the yield of good parts.
Still, it was an interesting mental exercise.
ps: I don't think addressing pixels on a round sensor would be difficult
at all especially if some firmware assistance was built into the chip.
Think of a modern disk drive. The driver reads or writes a chunk of
data staring at some linear address. It has no idea where that data is
actually stored on the disk. Anyone for polar coordinates? :-)
Chuck Norcutt
Carlos J. Santisteban wrote:
> Hi Chuck and all,
>
> I tried to visit your link, but it was already 'not found'...
>
> Joke or not, I don't see the point of a circular sensor anyway. Due to
> current IC's production method (circlular shapes do waste a lot of silicon
> wafer!) it wouldn't be any cheaper than a square sensor whose side equalled
> the circle's diameter, which in turn would have about 27.3% more pixels (x 4
> / pi) for the same pitch/density.
>
> Plus, addressing the pixels on a circular sensor would be a real nightmare
> for the decoding circuitry and/or firmware.
>
> Cheers,
--
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