On Tue, 22 Jun 2004 20:04:11 -0400, Bob wrote:

On Tue, 22 Jun 2004 21:58:47 -0400, paul wrote:

On Tue, 22 Jun 2004 01:11:13 -0400, Bob wrote:


Although they are cheaper and lighter, you don't really want to invest too
many DX lens, unless you believe we'll be stuck in 1.5x crop factor. You
can't use them on film cameras. If there are breakthrough in sensor size
development, the DX lens would be worthless.


Isn't someone already making a larger sensor? I'm sure I heard about one that is
about 95% film size... it's only a matter of time anyway...

As long as the sensors will be made out of silicon wafers the film sized
sensors will be expensive. A 24*36mm piece of silicon will always be much
more costly than the a 19*30mm.

A quick calculation with the following assumptions:
defects/cm2 = 0.3
cost 8" wafer = $1500 (I do not know the price of a processed wafer, but
it would not be to far away from this)

24*36mm = $750 note: 2 good dies per wafer!!!
19*30mm = $167 note: 9 good dies per wafer

if the process improves the cost will go down
say for a good fab the defects per cm2 is 0.2 the cost price (without
package) would go down:

24*36mm = $250 note: 6 good dies per wafer!!!
19*30mm = $88 note:17 good dies per wafer

I do not know the details of the processes used for the sensors, but the I
do know silicon fabs. And the number of defects will be closer to 0.3/cm2
than to 0.2/cm2

In short the sensor for with factor 1.5 will be between 3 and 5 times
cheaper than a full size sensor!

Paul

Interesting.... I guess it's not like a Pentium chip, you can't have any
errors... I understand that CPUs wire out the defects, and have tons of repeated
circuits... Maybe someone needs to make a different style sensor that can have
faults that can be replaced.

In memories you can build in redundancy, but how you would do that in an
optical sensor I would not know.

And I think you would not except a not working pixel in your sensor.
well maybe that is not true...
Question does anybody know how many not working pixels are allowed
in a camera? I assumed none and I hope they are all working in mine... I
guess they can hide them with some software which would allow for higher
yields and lower prices, anyone?

Paul