From: Bill Funk on
On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b(a)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.
From: David Dyer-Bennet on
Bill Funk wrote:
> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b(a)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).

From: Bill Funk on
On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b(a)dd-b.net>
wrote:

>Bill Funk wrote:
>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b(a)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.
From: David Dyer-Bennet on
Bill Funk wrote:
> On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b(a)dd-b.net>
> wrote:
>
>> Bill Funk wrote:
>>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b(a)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.
From: Roger N. Clark (change username to rnclark) on
David Dyer-Bennet wrote:
> Bill Funk wrote:
>> On Sat, 14 Apr 2007 15:13:11 -0500, David Dyer-Bennet <dd-b(a)dd-b.net>
>> wrote:
>>
>>> Bill Funk wrote:
>>>> On Fri, 13 Apr 2007 12:11:24 -0500, David Dyer-Bennet <dd-b(a)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