Closer to perfection (current camera sensors)

Some interesting work by Bill Claff (and others) with an interactive
chart on "photographic dynamic range" of (mainly) Nikon slr camera
sensors, dating back a few years:
http://home.comcast.net/~nikond70/Charts/PDR.htm

I've taken a screenshot he http://i41.tinypic.com/1zz75hd.png which
shows "pdr" for D200, D300, D7000, provisional (no data yet for D800 at
ISO400, and limited number of raw files) for D800 in "DX crop" mode,
and "ideal dx".

Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

* There's only about 1/2 stop "possible improvement" left (see D800 in
"dx crop mode vs "ideal dx") with bayer sensors.
* Getting there (to "ideal") requires perfect dyes in RGB filters,
perfect microlenses, no read noise. I don't think it can happen - we're
only going to see small gains in future.
* between the D3s and D4, there's a slight gain in PDR at low ISO from
read noise reduction, but little else - it stays about the same, but
with an increase in pixel density.
* We'll never see a pdr gain of the size of gain between the D200 and
D300, or D300 and D800 (dx crop mode).
* Megapixels can still be increased.
* BSI isn't likely to offer much improvement at current pixel densities
perhaps it might be able to offset losses if pixel densities increase
significantly - but I'm guessing that sensors will be oversampling long
before BSI is worth the effort with dslr sized sensors.
* Foveon (or another technology such as Nikon's patent with dichroic
mirrors reflecting RGB to sensels in a Bayer array) might offer some
improvement in QE.
* dx has hit the wall compared to Nikon FX (and Canon FX - except at low
ISO where read noise still limits pdr). Current FX models exceed "ideal
dx" pdr, so situations such as the D7000 exceeding the pdr of the D700
aren't likely to be seen again - dx can't "catch up".


Bill Claff's methodology could be wrong (or I've misinterpreted it), but
from my use of some of the cameras concerned, it seems spot on.

In article , Me says...
Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

No, an ideal sensor would be a full-colour sensor, not a Bayer one. But
at the moment full-colour sensor technology is not good enough yet.
--

Alfred Molon
------------------------------
Olympus E-series DSLRs and micro 4/3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site

On 10/03/2012 9:33 p.m., RichA wrote:
On Mar 9, 9:57 pm, wrote:
Some interesting work by Bill Claff (and others) with an interactive
chart on "photographic dynamic range" of (mainly) Nikon slr camera
sensors, dating back a few years:http://home.comcast.net/~nikond70/Charts/PDR.htm

I've taken a screenshot hehttp://i41.tinypic.com/1zz75hd.pngwhich
shows "pdr" for D200, D300, D7000, provisional (no data yet for D800 at
ISO400, and limited number of raw files) for D800 in "DX crop" mode,
and "ideal dx".

Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

* There's only about 1/2 stop "possible improvement" left (see D800 in
"dx crop mode vs "ideal dx") with bayer sensors.
* Getting there (to "ideal") requires perfect dyes in RGB filters,
perfect microlenses, no read noise. I don't think it can happen - we're
only going to see small gains in future.
* between the D3s and D4, there's a slight gain in PDR at low ISO from
read noise reduction, but little else - it stays about the same, but
with an increase in pixel density.
* We'll never see a pdr gain of the size of gain between the D200 and
D300, or D300 and D800 (dx crop mode).
* Megapixels can still be increased.
* BSI isn't likely to offer much improvement at current pixel densities
perhaps it might be able to offset losses if pixel densities increase
significantly - but I'm guessing that sensors will be oversampling long
before BSI is worth the effort with dslr sized sensors.
* Foveon (or another technology such as Nikon's patent with dichroic
mirrors reflecting RGB to sensels in a Bayer array) might offer some
improvement in QE.
* dx has hit the wall compared to Nikon FX (and Canon FX - except at low
ISO where read noise still limits pdr). Current FX models exceed "ideal
dx" pdr, so situations such as the D7000 exceeding the pdr of the D700
aren't likely to be seen again - dx can't "catch up".

Bill Claff's methodology could be wrong (or I've misinterpreted it), but
from my use of some of the cameras concerned, it seems spot on.

The 5DII rates better than the D4. Sure.

If that's what you read from the chart, god help you if you try to make
sense of a histogram on your camera LCD.

On 10/03/2012 10:48 p.m., Alfred Molon wrote:
In , Me says...
Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

No, an ideal sensor would be a full-colour sensor, not a Bayer one. But
at the moment full-colour sensor technology is not good enough yet.

I think I mentioned that. Yes, an "ideal" foveon outperforms an "ideal"
bayer sensor.

"Me" wrote in message
...
On 10/03/2012 10:48 p.m., Alfred Molon wrote:
In , Me says...
Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

No, an ideal sensor would be a full-colour sensor, not a Bayer one. But
at the moment full-colour sensor technology is not good enough yet.

I think I mentioned that. Yes, an "ideal" foveon outperforms an "ideal"
bayer sensor.

I suppose. But a real Bayer gets quite close to an ideal Bayer, whereas
Foveon needs 100% transparency to the bands not detected in the top two
layers, and that's never going to happen, not even close. Also, getting high
QE out of Foveon in the detection layers is going to be way harder.

Meanwhile, as I keep saying over and over again, Bayer is flipping amazing.
12MP FF Bayer makes 35mm film look sick at 12x18. There's just no
comparison. And 36MP FF Bayer is going to match 6x9 film at 16x24. This is
friggin' amazing: a measly 24x36mm of silicon competing with 56x92 mm of
film.

Which is to say, I don't get the folks complaining about the Bayer array +
AA filter technology. It produces amazing images, and trying to do better is
a fool's errand, since all you get is worse color/noise performance (real
life Foveon) and horrific artifacts (from leaving out the mathematically
required AA filter).

--
David J. Littleboy
Tokyo, Japan

In article , David J.
Littleboy wrote:

Which is to say, I don't get the folks complaining about the Bayer array +
AA filter technology. It produces amazing images, and trying to do better is
a fool's errand, since all you get is worse color/noise performance (real
life Foveon) and horrific artifacts (from leaving out the mathematically
required AA filter).

and colour shifts because foveon is not actually measuring red, green
and blue. the 3 layers need to be converted to rgb. worse, the colour
shifts vary depending on the subject and exposure, which makes it a
royal pain in the ass to fix.

In article , Alfred
Molon wrote:

Ideal DX would be defined by a Bayer type sensor with 100% quantum
efficiency and no read noise.

No, an ideal sensor would be a full-colour sensor, not a Bayer one. But
at the moment full-colour sensor technology is not good enough yet.

and not likely to ever be, plus if you oversample with bayer, full
colour sensors are not needed.

On 3/10/2012 7:49 AM, David J. Littleboy wrote:


Which is to say, I don't get the folks complaining about the Bayer array +
AA filter technology. It produces amazing images, and trying to do better is
a fool's errand,

on a single ship: three chip cameras with dichroic filters are much better.

Doug McDonald

On Sat, 10 Mar 2012 09:59:38 -0600, Doug McDonald
wrote:

On 3/10/2012 7:49 AM, David J. Littleboy wrote:


Which is to say, I don't get the folks complaining about the Bayer array +
AA filter technology. It produces amazing images, and trying to do better is
a fool's errand,

on a single ship: three chip cameras with dichroic filters are much better.

Would that be a sailing ship or a cabin cruiser?

On 2012-03-10 10:59 , Doug McDonald wrote:
On 3/10/2012 7:49 AM, David J. Littleboy wrote:


Which is to say, I don't get the folks complaining about the Bayer
array +
AA filter technology. It produces amazing images, and trying to do
better is
a fool's errand,

on a single ship: three chip cameras with dichroic filters are much better.

With weight, volume, cost.

It amazes me that ENG cameras still use the 3 CCD system. With larger
bayer sensors the S/N will be much better. I would venture that it is
the lens base that is a barrier to moving to a larger sensor.

Cinema cameras have gone to digital with single sensor (bayer).

--
"I was gratified to be able to answer promptly, and I did.
I said I didn't know."
-Samuel Clemens.