Bayer filter removal

"David Dyer-Bennet" <dd-b.RemoveThis@dd-b.net> wrote in message
news:461fb9b6$0$952$8046368a@newsreader.iphouse.net...
> Is any company offering removal of the Bayer filter from a Nikon-mount
> DSLR? Particularly the D40? (I suspect it may not be feasible due to the
> stacking order and how the microlenses, AA, IR cut, and Bayer are
> combined, and other issues, and I haven't been able to Google up much, but
> I thought asking might still turn something up.) I'm interested in a
> high-sensitivity B&W camera for low-light situations.

Interesting idea. Would one necessarily lose the micro-lenses as well and
would that mitigate against removal? I don't really know, by the way. Here
is an interesting link that might be helpful:
http://micro.magnet.fsu.edu/primer/digitalimaging/cmosimagesensors.html
 >> Stay informed about: Bayer filter removal 

Charles Schuler wrote:
> "David Dyer-Bennet" <dd-b.RemoveThis@dd-b.net> wrote in message
> news:461fb9b6$0$952$8046368a@newsreader.iphouse.net...
>> Is any company offering removal of the Bayer filter from a Nikon-mount
>> DSLR? Particularly the D40? (I suspect it may not be feasible due to the
>> stacking order and how the microlenses, AA, IR cut, and Bayer are
>> combined, and other issues, and I haven't been able to Google up much, but
>> I thought asking might still turn something up.) I'm interested in a
>> high-sensitivity B&W camera for low-light situations.
>
> Interesting idea. Would one necessarily lose the micro-lenses as well and
> would that mitigate against removal? I don't really know, by the way. Here
> is an interesting link that might be helpful:
> http://micro.magnet.fsu.edu/primer/digitalimaging/cmosimagesensors.html

Interesting, and had some detail I didn't know, thanks!

Doesn't mention where the IR-block filter is in all that, either, or the
optical anti-aliasing filter. I suspect it varies considerably.

I suspect that the microlenses would be a major loss; but I suppose
trying it with various lenses would be interesting. The worst
complaints are about ultra-wide lenses, and I don't use them in the
conditions I want this camera for. (I'm not *at all* sure that I'm
prepared (mostly financially) to be the first experimenter here ).
 >> Stay informed about: Bayer filter removal 

"David Dyer-Bennet" <dd-b RemoveThis @dd-b.net> wrote in message
news:461fee3b$0$952$8046368a@newsreader.iphouse.net...
> Charles Schuler wrote:
>> "David Dyer-Bennet" <dd-b RemoveThis @dd-b.net> wrote in message
>> news:461fb9b6$0$952$8046368a@newsreader.iphouse.net...
>>> Is any company offering removal of the Bayer filter from a Nikon-mount
>>> DSLR? Particularly the D40? (I suspect it may not be feasible due to
>>> the stacking order and how the microlenses, AA, IR cut, and Bayer are
>>> combined, and other issues, and I haven't been able to Google up much,
>>> but I thought asking might still turn something up.) I'm interested in
>>> a high-sensitivity B&W camera for low-light situations.
>>
>> Interesting idea. Would one necessarily lose the micro-lenses as well
>> and would that mitigate against removal? I don't really know, by the
>> way. Here is an interesting link that might be helpful:
>> http://micro.magnet.fsu.edu/primer/digitalimaging/cmosimagesensors.html
>
> Interesting, and had some detail I didn't know, thanks!
>
> Doesn't mention where the IR-block filter is in all that, either, or the
> optical anti-aliasing filter. I suspect it varies considerably.
>
> I suspect that the microlenses would be a major loss; but I suppose trying
> it with various lenses would be interesting. The worst complaints are
> about ultra-wide lenses, and I don't use them in the conditions I want
> this camera for. (I'm not *at all* sure that I'm prepared (mostly
> financially) to be the first experimenter here ).

The stacking technology of the various filters is an interesting issue. The
IR filter must be near the top, at least in some cases, since one can find
sources such as this one:
http://www.abe.msstate.edu/~jwooten/camera/lense.html

Now that digital cameras are enjoying rather brisk sales, I wonder if
specialized models are near. Canon's astral model is but one indicator:
http://www.digitalcamerainfo.com/content/Astral-Specialized-Canon-Comi...to-US-i

You want a B&W camera with the best possible sensitivity, and you are not
alone. I'd guess it is coming soon.
 >> Stay informed about: Bayer filter removal 

"David Dyer-Bennet" <dd-b.TakeThisOut@dd-b.net> schrieb im Newsbeitrag
news:461fb9b6$0$952$8046368a@newsreader.iphouse.net...
> Is any company offering removal of the Bayer filter from a Nikon-mount
> DSLR? Particularly the D40? (I suspect it may not be feasible due to the
> stacking order and how the microlenses, AA, IR cut, and Bayer are
> combined, and other issues, and I haven't been able to Google up much, but
> I thought asking might still turn something up.) I'm interested in a
> high-sensitivity B&W camera for low-light situations.

Certainly nobody will do that, Also you could easily buy a couple of D1 MK 3
's plus assorted lenses for the cost of doing that. It would be a more
realistic approach to cool the sensor with liquid nitrogen (and float the
camera with dry nitrogen to keep water out) to achieve a higher signal /
noise ratio. A full frame sensor camera or a larger than full frame camera
(like Mamyia) would be the easiest solution for achieving improved signal to
noise ratio.

In production multiple sensors are processed on a wafer (4", 6" or 200 mm)
and only separated after they have run through all the processing steps
(except for bonding).

Even if a pin compatible black and white version of the original sensor
would exist, it would need custom developed image processing (ASIC's and
firmware) because processing black and white pixels can not use the same
weighting used as for processing the signals from a Bayer matrix sensor.
Recording in RAW and using a customized external converter program to obtain
an image from that would be slightly easier - but probably not for any *.nef
files, as these are not true RAW but store pre processed data. The camera
display would also be pretty useless, but I did not have that on my film
cameras and could still take pictures.
 >> Stay informed about: Bayer filter removal 

cgiorgio wrote:
> "David Dyer-Bennet" <dd-b.RemoveThis@dd-b.net> schrieb im Newsbeitrag
> news:461fb9b6$0$952$8046368a@newsreader.iphouse.net...
>> Is any company offering removal of the Bayer filter from a Nikon-mount
>> DSLR? Particularly the D40? (I suspect it may not be feasible due to the
>> stacking order and how the microlenses, AA, IR cut, and Bayer are
>> combined, and other issues, and I haven't been able to Google up much, but
>> I thought asking might still turn something up.) I'm interested in a
>> high-sensitivity B&W camera for low-light situations.
>
> Certainly nobody will do that, Also you could easily buy a couple of D1 MK 3
> 's plus assorted lenses for the cost of doing that.

I can't tell if you know more than me on this topic, or less. I don't
believe that the Bayer filter is fabricated directly on the sensor as
part of the manufacturing process in most cases, but I don't have a good
specific source to point to, either.

I do know that a number of places offer cameras with the IR-block
filters removed, and there are instructions floating around for how to
do that yourself in various models. The cost for the commercial
versions is modest.

> It would be a more
> realistic approach to cool the sensor with liquid nitrogen (and float the
> camera with dry nitrogen to keep water out) to achieve a higher signal /
> noise ratio. A full frame sensor camera or a larger than full frame camera
> (like Mamyia) would be the easiest solution for achieving improved signal to
> noise ratio.

I very much doubt that LN cooling is feasible today for a camera I could
use to take photos at dimly-lit music parties.

A larger-sensor camera would have lower noise, but it would use much
slower lenses; this is why photojournalism and especially street
photography migrated to 35mm in the first place.

> In production multiple sensors are processed on a wafer (4", 6" or 200 mm)
> and only separated after they have run through all the processing steps
> (except for bonding).
>
> Even if a pin compatible black and white version of the original sensor
> would exist, it would need custom developed image processing (ASIC's and
> firmware) because processing black and white pixels can not use the same
> weighting used as for processing the signals from a Bayer matrix sensor.
> Recording in RAW and using a customized external converter program to obtain
> an image from that would be slightly easier - but probably not for any *.nef
> files, as these are not true RAW but store pre processed data. The camera
> display would also be pretty useless, but I did not have that on my film
> cameras and could still take pictures.

Digital IR photos are frequently taken by using a visible-light-blocking
filter. This greatly reduces the sensitivity, but usable IR photos can
be taken with most digital cameras this way. I believe the dyes in the
Bayer filter are mostly transparent in the infrared (or at least all the
colors are about the same density in the infrared). With P&S cameras,
the preview is reasonably accurate, and looks mostly monochrome, as does
the captured image. So I'm not at all sure that a rework of the
firmware (or external processing using a true raw file) would be
necessary to achieve usable B&W results. (I've shot infrared with an
Epson 850Z and a Fuji S2 using the Hoya r72 visible-light-blocking
filter). (A rework of the firmware or external RAW processing with a
special B&W version of the software might give some real increase in
resolution, though.)
 >> Stay informed about: Bayer filter removal 

"cgiorgio" <udlike.RemoveThis@toknow.org> wrote in news:evot27$cd0$01$1@news.t-
online.com:

> Even if a pin compatible black and white version of the original sensor
> would exist, it would need custom developed image processing (ASIC's and
> firmware) because processing black and white pixels can not use the same
> weighting used as for processing the signals from a Bayer matrix sensor.

All a firmware or hardware needs to do is use a certain WB setting to
display the grey RAW data as grey RGB on the LCD, or in the JPEGs, and bias
the metering. The only artifacts might be slight color fringing in high-
frequency high-contrast content, when zoomed in sufficiently. If the
camera already has B&W mode (intended for the CFA), that won't even happen.

--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS.RemoveThis@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
 >> Stay informed about: Bayer filter removal 

"David Dyer-Bennet" <dd-b.RemoveThis@dd-b.net> wrote:
> Is any company offering removal of the Bayer filter from a Nikon-mount
> DSLR? Particularly the D40?

Unlikely. Although I've not looked into the Sony APS-C sensors, their P&S
sensors build both the microlenses and color filters into the chip. Since
even the slightest registration error would be a complete disaster, it's
unlikely that the color filters are any different on the APS-C sensors.

> (I suspect it may not be feasible due to the stacking order and how the
> microlenses, AA, IR cut, and Bayer are combined, and other issues, and I
> haven't been able to Google up much, but I thought asking might still turn
> something up.) I'm interested in a high-sensitivity B&W camera for
> low-light situations.

Since the color filters are largely transparent to IR, the best you get is a
reasonably sensitive IR camera by removing the IR cut filter (and maybe the
low-pass filter).

High on my wish list is a dSLR with interchangeable sensors. It should be
possible. A 5DII with both a 16MP color sensor and an 8MP B&W sensor would
be seriously neat. I'd certainly cough up between US$700 and US$1000 for the
8MP sensor.

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Bayer filter removal 

David J. Littleboy wrote:
> "David Dyer-Bennet" <dd-b DeleteThis @dd-b.net> wrote:
>> Is any company offering removal of the Bayer filter from a Nikon-mount
>> DSLR? Particularly the D40?
>
> Unlikely. Although I've not looked into the Sony APS-C sensors, their P&S
> sensors build both the microlenses and color filters into the chip. Since
> even the slightest registration error would be a complete disaster, it's
> unlikely that the color filters are any different on the APS-C sensors.

And that's the answer I'm getting from people who actually perform
conversions, too. I'm not surprised; but I was hoping my vague ideas
were *wrong*. Oh well.

>> (I suspect it may not be feasible due to the stacking order and how the
>> microlenses, AA, IR cut, and Bayer are combined, and other issues, and I
>> haven't been able to Google up much, but I thought asking might still turn
>> something up.) I'm interested in a high-sensitivity B&W camera for
>> low-light situations.
>
> Since the color filters are largely transparent to IR, the best you get is a
> reasonably sensitive IR camera by removing the IR cut filter (and maybe the
> low-pass filter).

That has its own temptations, but completely different ones. And not so
tempting for me (though I've done IR a little with my last two digicams).

> High on my wish list is a dSLR with interchangeable sensors. It should be
> possible. A 5DII with both a 16MP color sensor and an 8MP B&W sensor would
> be seriously neat. I'd certainly cough up between US$700 and US$1000 for the
> 8MP sensor.

Something like that would be really nice.
 >> Stay informed about: Bayer filter removal 

On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b.DeleteThis@dd-b.net>
wrote:

>Is any company offering removal of the Bayer filter from a Nikon-mount
>DSLR? Particularly the D40? (I suspect it may not be feasible due to
>the stacking order and how the microlenses, AA, IR cut, and Bayer are
>combined, and other issues, and I haven't been able to Google up much,
>but I thought asking might still turn something up.) I'm interested in
>a high-sensitivity B&W camera for low-light situations.

Since the processing done in-camera assumes the Bayer filter is there,
wouldn't removing it (if it were possible) seriously farkle the
output?
I suppose if you shot in RAW only, the RAW file wouldn't be farkled,
but how would you then process the RAW file, as all processing
software assumes the presence of a Bayer filter?

--
THIS IS A SIG LINE; NOT TO BE TAKEN SERIOUSLY!

The White House admitted on Wednesday that
e-mails about official business in Karl Rove's
office were erased. The deleted e-mails were
sent on Republican Party accounts instead of
White House accounts to avoid a law that
requires preservation of government records.
It doesn't clog up the landfills like Hillary's
shredder did for eight years.
 >> Stay informed about: Bayer filter removal 

Bill Funk wrote:
> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b DeleteThis @dd-b.net>
> wrote:
>
>> Is any company offering removal of the Bayer filter from a Nikon-mount
>> DSLR? Particularly the D40? (I suspect it may not be feasible due to
>> the stacking order and how the microlenses, AA, IR cut, and Bayer are
>> combined, and other issues, and I haven't been able to Google up much,
>> but I thought asking might still turn something up.) I'm interested in
>> a high-sensitivity B&W camera for low-light situations.
>
> Since the processing done in-camera assumes the Bayer filter is there,
> wouldn't removing it (if it were possible) seriously farkle the
> output?

Not really; if you present a camera with a B&W scene it will render it
in B&W, not fake colors. And if you present it with an infrared scene
(with a visible light block) you'll get pretty much a monochrome
rendering, even if the camera is set in a "color" mode (and of course
most of them can be set for B&W anyway).

> I suppose if you shot in RAW only, the RAW file wouldn't be farkled,
> but how would you then process the RAW file, as all processing
> software assumes the presence of a Bayer filter?

Well, I have seen a specialized RAW processor mentioned for infrared
shots that uses all the pixels (the Bayer filter cells are transparent
in the infrared). And if necessary one can be written (I'm a software
developer professionally; so while I'd prefer to avoid that level of
involvement, if that were the *only* block, I'd take it on).
 >> Stay informed about: Bayer filter removal 

On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b.RemoveThis@dd-b.net>
wrote:

>Bill Funk wrote:
>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b.RemoveThis@dd-b.net>
>> wrote:
>>
>>> Is any company offering removal of the Bayer filter from a Nikon-mount
>>> DSLR? Particularly the D40? (I suspect it may not be feasible due to
>>> the stacking order and how the microlenses, AA, IR cut, and Bayer are
>>> combined, and other issues, and I haven't been able to Google up much,
>>> but I thought asking might still turn something up.) I'm interested in
>>> a high-sensitivity B&W camera for low-light situations.
>>
>> Since the processing done in-camera assumes the Bayer filter is there,
>> wouldn't removing it (if it were possible) seriously farkle the
>> output?
>
>Not really; if you present a camera with a B&W scene it will render it
>in B&W, not fake colors. And if you present it with an infrared scene
>(with a visible light block) you'll get pretty much a monochrome
>rendering, even if the camera is set in a "color" mode (and of course
>most of them can be set for B&W anyway).

It still seems that removing the Bayer filter and shooting a color
scene will seriously confuse the software; for example, without the
filter in place, how will it know how to represent green? (RGBG
putting twice as much green data into the system)
Yes, the system will render B&W scenes properly, but what about color
scenes?
>
>> I suppose if you shot in RAW only, the RAW file wouldn't be farkled,
>> but how would you then process the RAW file, as all processing
>> software assumes the presence of a Bayer filter?
>
>Well, I have seen a specialized RAW processor mentioned for infrared
>shots that uses all the pixels (the Bayer filter cells are transparent
>in the infrared). And if necessary one can be written (I'm a software
>developer professionally; so while I'd prefer to avoid that level of
>involvement, if that were the *only* block, I'd take it on).

Well, sure, if you can do it, that's fine.
However, for general (or even *limited* general) use, that's
impractical; the distributed software model (free or paid) would be
needed.

Plus, as you point out, the camera can be set to B&W output already,
and it can also be done in post.
There was another recent thread (here, I think) about converting a
current DSLR into a B&W DSLR with a sensor of fewer MPs. My thoughts
are the same as here: why? It can be done now, and the converted
camera would be more expensive, and less functional.
"Please, Mr. camera maker, make a camera that does less and costs
more."
I don't see it.

--
THIS IS A SIG LINE; NOT TO BE TAKEN SERIOUSLY!

The White House admitted on Wednesday that
e-mails about official business in Karl Rove's
office were erased. The deleted e-mails were
sent on Republican Party accounts instead of
White House accounts to avoid a law that
requires preservation of government records.
It doesn't clog up the landfills like Hillary's
shredder did for eight years.
 >> Stay informed about: Bayer filter removal 

Bill Funk wrote:
> On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b.RemoveThis@dd-b.net>
> wrote:
>
>> Bill Funk wrote:
>>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b.RemoveThis@dd-b.net>
>>> wrote:
>>>
>>>> Is any company offering removal of the Bayer filter from a Nikon-mount
>>>> DSLR? Particularly the D40? (I suspect it may not be feasible due to
>>>> the stacking order and how the microlenses, AA, IR cut, and Bayer are
>>>> combined, and other issues, and I haven't been able to Google up much,
>>>> but I thought asking might still turn something up.) I'm interested in
>>>> a high-sensitivity B&W camera for low-light situations.
>>> Since the processing done in-camera assumes the Bayer filter is there,
>>> wouldn't removing it (if it were possible) seriously farkle the
>>> output?
>> Not really; if you present a camera with a B&W scene it will render it
>> in B&W, not fake colors. And if you present it with an infrared scene
>> (with a visible light block) you'll get pretty much a monochrome
>> rendering, even if the camera is set in a "color" mode (and of course
>> most of them can be set for B&W anyway).
>
> It still seems that removing the Bayer filter and shooting a color
> scene will seriously confuse the software; for example, without the
> filter in place, how will it know how to represent green? (RGBG
> putting twice as much green data into the system)
> Yes, the system will render B&W scenes properly, but what about color
> scenes?

Shooting infrared the simple way (visible-blocking filter over the lens,
no camera mods) is presenting essentially the same signal to the
sensor that removal of the Bayer filter would; it sees roughly equal
values. And that works fine in many, many cameras.

>>> I suppose if you shot in RAW only, the RAW file wouldn't be farkled,
>>> but how would you then process the RAW file, as all processing
>>> software assumes the presence of a Bayer filter?
>> Well, I have seen a specialized RAW processor mentioned for infrared
>> shots that uses all the pixels (the Bayer filter cells are transparent
>> in the infrared). And if necessary one can be written (I'm a software
>> developer professionally; so while I'd prefer to avoid that level of
>> involvement, if that were the *only* block, I'd take it on).
>
> Well, sure, if you can do it, that's fine.
> However, for general (or even *limited* general) use, that's
> impractical; the distributed software model (free or paid) would be
> needed.

Well, if I took the trouble, I'd distribute it.

> Plus, as you point out, the camera can be set to B&W output already,
> and it can also be done in post.
> There was another recent thread (here, I think) about converting a
> current DSLR into a B&W DSLR with a sensor of fewer MPs. My thoughts
> are the same as here: why? It can be done now, and the converted
> camera would be more expensive, and less functional.
> "Please, Mr. camera maker, make a camera that does less and costs
> more."
> I don't see it.

The one I want does more -- it's 1.5 stops more sensitive and of
significantly higher resolution with the same pixel pitch.
 >> Stay informed about: Bayer filter removal 

David Dyer-Bennet wrote:
> Bill Funk wrote:
>> On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b.DeleteThis@dd-b.net>
>> wrote:
>>
>>> Bill Funk wrote:
>>>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b.DeleteThis@dd-b.net>
>>>> wrote:
>>>>
>>>>> Is any company offering removal of the Bayer filter from a
>>>>> Nikon-mount DSLR? Particularly the D40? (I suspect it may not be
>>>>> feasible due to the stacking order and how the microlenses, AA, IR
>>>>> cut, and Bayer are combined, and other issues, and I haven't been
>>>>> able to Google up much, but I thought asking might still turn
>>>>> something up.) I'm interested in a high-sensitivity B&W camera for
>>>>> low-light situations.
>>>> Since the processing done in-camera assumes the Bayer filter is there,
>>>> wouldn't removing it (if it were possible) seriously farkle the
>>>> output?
>>> Not really; if you present a camera with a B&W scene it will render
>>> it in B&W, not fake colors. And if you present it with an infrared
>>> scene (with a visible light block) you'll get pretty much a
>>> monochrome rendering, even if the camera is set in a "color" mode
>>> (and of course most of them can be set for B&W anyway).
>>
>> It still seems that removing the Bayer filter and shooting a color
>> scene will seriously confuse the software; for example, without the
>> filter in place, how will it know how to represent green? (RGBG
>> putting twice as much green data into the system)
>> Yes, the system will render B&W scenes properly, but what about color
>> scenes?
>
> Shooting infrared the simple way (visible-blocking filter over the lens,
> no camera mods) is presenting essentially the same signal to the sensor
> that removal of the Bayer filter would; it sees roughly equal values.
> And that works fine in many, many cameras.
>
>>>> I suppose if you shot in RAW only, the RAW file wouldn't be farkled,
>>>> but how would you then process the RAW file, as all processing
>>>> software assumes the presence of a Bayer filter?
>>> Well, I have seen a specialized RAW processor mentioned for infrared
>>> shots that uses all the pixels (the Bayer filter cells are
>>> transparent in the infrared). And if necessary one can be written
>>> (I'm a software developer professionally; so while I'd prefer to
>>> avoid that level of involvement, if that were the *only* block, I'd
>>> take it on).
>>
>> Well, sure, if you can do it, that's fine.
>> However, for general (or even *limited* general) use, that's
>> impractical; the distributed software model (free or paid) would be
>> needed.
>
> Well, if I took the trouble, I'd distribute it.
>
>> Plus, as you point out, the camera can be set to B&W output already,
>> and it can also be done in post.
>> There was another recent thread (here, I think) about converting a
>> current DSLR into a B&W DSLR with a sensor of fewer MPs. My thoughts
>> are the same as here: why? It can be done now, and the converted
>> camera would be more expensive, and less functional.
>> "Please, Mr. camera maker, make a camera that does less and costs
>> more."
>> I don't see it.
>
> The one I want does more -- it's 1.5 stops more sensitive and of
> significantly higher resolution with the same pixel pitch.

Hi,

Removal of the Bayer filter would give a lot more light throughput
than 1.5 stops. You have not only the transmission of the
filters but their bandwidths too as factors. If you removed the IR filter
too, I think I computed once that you would gain about 50x in speed!
Removal of the blur filter would also make very sharp B&W images.

Some programs, like dcraw or imagesplus allow you to extract
the raw data with no Bayer interpolation, so software exists
to get the data out and into a proper form to take advantage
of the system.

There are companies that remove the IR filter (Heutech (sp?) for one),
but removing the Bayer filters would require removal from the
surface of the sensor, and I don't know anyone who does that.

I would buy a 20D class black and white camera if such were
to come on the market.

Roger
 >> Stay informed about: Bayer filter removal