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Am I oversharpening

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Anonymous
May 29, 2005 11:13:03 PM

Archived from groups: rec.photo.digital (More info?)

Please take a look at the attached link. I am still trying to get the hang
of this Unsharp Mask Thing. Are these oversharpened.

Canon 20D - Raw - 75-300 IS Zoom

Thanks.

http://spaces.msn.com/members/fleetingglimpse/PersonalS...!1pioagCJB9TmXNBFRp_AlULA!741&_c=PhotoAlbum

~Rikk

website: www.fleetingglimpse.com
blog: http://spaces.msn.com/members/fleetingglmpse/

More about : oversharpening

Anonymous
May 29, 2005 11:13:04 PM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:
> Please take a look at the attached link. I am still trying to get the hang
> of this Unsharp Mask Thing. Are these oversharpened.


I don't think so. Oversharpened pics show halos around edges, emphasized
noise and a sort of flattened washed, out electric haze look.

PS If you sharpened for print size then reduced for web, we won't see
that at all. It is size dependent.


>
> Canon 20D - Raw - 75-300 IS Zoom
>
> Thanks.
>
> http://spaces.msn.com/members/fleetingglimpse/PersonalS...!1pioagCJB9TmXNBFRp_AlULA!741&_c=PhotoAlbum
>
> ~Rikk
>
> website: www.fleetingglimpse.com
> blog: http://spaces.msn.com/members/fleetingglmpse/
>
>

--
Paul Furman
http://www.edgehill.net/1
san francisco native plants
Anonymous
May 30, 2005 1:38:46 AM

Archived from groups: rec.photo.digital (More info?)

No, I sharpened them last step.

I am a film photog learning the digital game. When I compare the RAW files
saved as TIFF to my processed files, the processed files look unreal. Too
sharp. Maybe I am seeing it backwards and the Raw is too soft.

Thanks.
Related resources
Anonymous
May 30, 2005 1:38:47 AM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:

> No, I sharpened them last step.
>
> I am a film photog learning the digital game. When I compare the RAW files
> saved as TIFF to my processed files, the processed files look unreal. Too
> sharp. Maybe I am seeing it backwards and the Raw is too soft.


RAW files from a digital camera are indeed very soft and low contrast. I
don't think anybody shoots digital without some sharpening. The contrast
almost certainly needs to be increased too but most software will do
that to some sort of default without even asking. Many DSLRs shoot jpegs
that are muddy looking compared to point & shoot digitals so there is
room to adjust with software & the pictures are not already blown out.

Set the defaults in your raw converter to suit typical shots to give
them punch then just relax the sharpening for high ISO noisy exceptions
& relax contrast for high contrast pictures.

You won't see a lot of the "oversharpening" when printed. On a computer
you can zoom in & obsess on every detail but it'll be softer in a print.

PS I don't know how this all compares to film & I'm fairly new to all
this myself.

--
Paul Furman
http://www.edgehill.net/1
san francisco native plants
May 30, 2005 4:15:03 AM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:

> Please take a look at the attached link. I am still trying to get the hang
> of this Unsharp Mask Thing. Are these oversharpened.
>


Not really.


The only thing I see is some of the sharpening is being applied to OOF parts
of the image which can be distracting and cause the bokeh of the lenes to
look extra harsh.

I'm a BIG fan of ultrasharpen which selectively applies sharpening to an
image by finding the edges and letting you tweak two different sharpening
'masks' (using the PS levels tool on the masks) which is used to apply the
sharpening at two different levels of sharpening. My "default" is radius
1.6 100% then the second pass at .6 radius at 80%. Here's a screen shot of
one of these masks being made on an image.

http://img.villagephotos.com/p/2005-1/937049/ultrasharp...

Where the black is, it sharpens the most and varies through the shades of
gray till it ignores the white part totally. This elimates halos and allows
more sharpening without ruining the background or cranking up any noise the
image may have etc. As you can see on this mask it would sharpen the bird
and branch but ignore the smooth background part of the image which you
really wouldn't want any sharpening applied to.

This isn't a great bird shot, was one of my first attempts, but isn't awful
either. Been better if the bird wasn't in the shade.

Anyway this was what it looks like after sharpening with this tool..

http://img.villagephotos.com/p/2005-1/937049/bird2.jpg

It's a great tool and only costs $10.
--

Stacey
Anonymous
May 30, 2005 8:16:03 AM

Archived from groups: rec.photo.digital (More info?)

On 5/29/05 7:13 PM, in article PUsme.17445$cP2.6248@fe06.lga, "Celtic Boar"
<extraneous@charter.net> wrote:

> Please take a look at the attached link. I am still trying to get the hang
> of this Unsharp Mask Thing. Are these oversharpened.
>
> Canon 20D - Raw - 75-300 IS Zoom
>
> Thanks.
>
> http://spaces.msn.com/members/fleetingglimpse/PersonalS...
> um_spaHandler=TWljcm9zb2Z0LlNwYWNlcy5XZWIuUGFydHMuUGhvdG9BbGJ1bS5GdWxsTW9kZUNv
> bnRyb2xsZXI%24&_c11_PhotoAlbum_spaFolderID=cns!1pioagCJB9TmXNBFRp_AlULA!741&_c
> =PhotoAlbum
>
> ~Rikk
>
> website: www.fleetingglimpse.com
> blog: http://spaces.msn.com/members/fleetingglmpse/
>
>
Your images do not look over sharpened to me. Also, when images are printed
on an inkjet they will almost always look softer than they do on your
monitor.
Chuck
Anonymous
May 30, 2005 11:16:38 AM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:
> Please take a look at the attached link. I am still trying to get the hang
> of this Unsharp Mask Thing. Are these oversharpened.
>
> Canon 20D - Raw - 75-300 IS Zoom
>
> Thanks.

I couldn't find any oringals there so there is no way to evaluate the
images for sharpness. In general, if you are sharpening at all then
you are oversharpening.

Global digital sharpening tends to flatten or even invert the 3D nature
of an image, since contrast is strengthened pixel by pixel, without
regard to subject depth or the optics at play. The picture has to be
really soft or taken OOF to get benefits of digital sharpening above
the cost watermarking the image "from digital."
May 30, 2005 2:07:51 PM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:
> No, I sharpened them last step.
>
> I am a film photog learning the digital game. When I compare the RAW files
> saved as TIFF to my processed files, the processed files look unreal. Too
> sharp. Maybe I am seeing it backwards and the Raw is too soft.
>
> Thanks.
>
>
AS someone else said, it is hard to tell from the low-resolution pix that you posted. It
would be better if you showed a critical part of the image at higher resolution.

I find that almost any digital camera shot or scanned photo benefits from one step of
sharpening, and it is not always the unsharp mask that works best. A second step of
sharpening may make it noticably worse. It depends on the nature of the photo, and your
judgment. One of the nice things about digital darkroom work is the ease and
inexpensiveness of backing off from an unsatisfactory result. I use Paint Shop Pro, and
save photos in the PSP format as I go through the editing process, so that I can always go
back several steps, even if I pick up the process a day or more later.
Anonymous
May 30, 2005 2:31:58 PM

Archived from groups: rec.photo.digital (More info?)

Celtic Boar wrote:

> To clarify, I have added an unprocessed image to the same link. The Blue
> Heron Stalking now exists as a preprocessed and a post processed image.
> Perhaps this will give a better frame of reference.
>
> Thanks to all
>
> ~Rikk
>
> http://spaces.msn.com/members/fleetingglimpse/PersonalS...!1pioagCJB9TmXNBFRp_AlULA!741&_c=PhotoAlbumwebsite: www.fleetingglimpse.com blog: http://spaces.msn.com/members/fleetingglmpse/


It still doesn't look oversharpened but the contrast is very extreme.
Maybe the black background makes a more dramatic shot though.


--
Paul Furman
http://www.edgehill.net/1
san francisco native plants
Anonymous
May 30, 2005 5:21:28 PM

Archived from groups: rec.photo.digital (More info?)

George Preddy wrote:

> In general, if you are sharpening at all then
> you are oversharpening.

This is an untrue statement. Sharpening is part
of any proper digital workflow. Look here:
http://www.luminous-landscape.com/techniques/process.sh...

> Global digital sharpening tends to flatten or even
> invert the 3D nature of an image, since contrast
> is strengthened pixel by pixel, without regard to
> subject depth or the optics at play. The picture
> has to be really soft or taken OOF to get benefits
> of digital sharpening above the cost watermarking
> the image "from digital."

Huh?

For a good primer on sharpening, look here:
http://www.luminous-landscape.com/tutorials/sharpness.s...

or an alternative, try this:
http://www.luminous-landscape.com/tutorials/high-pass-s...

Here is another good tutorial on USM:
http://www.creativepro.com/story/feature/11242-1.html

Here is MS's version of the comment that Bayer filtering is
responsible for the necessity of USM in the first place:
http://www.microsoft.com/windowsxp/using/digitalphotogr...
May 30, 2005 5:30:17 PM

Archived from groups: rec.photo.digital (More info?)

Paul Furman wrote:

>>
http://spaces.msn.com/members/fleetingglimpse/PersonalS...!1pioagCJB9TmXNBFRp_AlULA!741&_c=PhotoAlbumwebsite:
>> www.fleetingglimpse.com blog:
>> http://spaces.msn.com/members/fleetingglmpse/
>
>
> It still doesn't look oversharpened but the contrast is very extreme.
>

I agree the contrast seems to high but the original shot looks -really-
flat. Maybe something in between those extreams would work?
--

Stacey
Anonymous
May 30, 2005 5:42:21 PM

Archived from groups: rec.photo.digital (More info?)

C Wright wrote:
> On 5/30/05 9:16 AM, in article
> 1117462598.038828.135100@g44g2000cwa.googlegroups.com,
> "george_preddy@yahoo.com" <george_preddy@yahoo.com> wrote:
>
> >
> >
> > Celtic Boar wrote:
> >> Please take a look at the attached link. I am still trying to get the hang
> >> of this Unsharp Mask Thing. Are these oversharpened.
> >>
> >> Canon 20D - Raw - 75-300 IS Zoom
> >>
> >> Thanks.
> >
> > I couldn't find any oringals there so there is no way to evaluate the
> > images for sharpness. In general, if you are sharpening at all then
> > you are oversharpening.
> >
> > Global digital sharpening tends to flatten or even invert the 3D nature
> > of an image, since contrast is strengthened pixel by pixel, without
> > regard to subject depth or the optics at play. The picture has to be
> > really soft or taken OOF to get benefits of digital sharpening above
> > the cost watermarking the image "from digital."
> >
> Considering your reputation in this group

There are 17 different George Preddys posting here, which one are you?

> I hesitate to reply at all but for
> the sake of potential newer dlsr users I can't let this statement stand!
> Unless someone has optional in-camera sharpness cranked way up dlsr's are
> noted for producing soft images - this is by the manufacturer's design.

No, it is the Bayer design. Since all Bayer cameras (all digitals
except Foveon based) output images that are already upscaled by 400%.

P&S's have harsh built in digital sharpening that can't be changed.
DSLRs are no softer, they stop short of oversharpening everything
before you see the image.

My point stands. Digital sharpening ruins images because it plows
through every pixel blindly, instead of leaving sharpness/blur to
optics. That is why film lovers hate digital, the result is flat and
lifeless, often even inverted.

If you sharpnen digitally, you are simply exceeding the capabilites of
your camera at the expense of quality. The only proper way to handle
digital images that are breaking down is to print them at the size they
were intended. There are no acceptable algorithmic crutches that can
substitute for sensor count.

> Most all advanced amateurs and pros prefer it this way and will use some
> sort of post processing program and either leave their images soft or
> sharpen as desired. Many, many images benefit from sharpening and to say
> that "In general, if you are sharpening at all then your are
> oversharpening." is just plain wrong! As far as the rest of your statement
> about sharpening tending to tending to "flatten" or "invert the 3D nature"
> of an image - huh!

If your camera needs sharpening, the only quality solution is to
downsize the already upscaled image to what your camera's sensor count
actually supports.

Bayer images are properly viewed at their optical, not recorded,
resolution. That is, 25% of the recorded size, or a complete dedicated
RGB sensor triplet for every presented color pixel.

If you are printing on paper, this is done for you. At smaller print
dimensions the image will look very sharp due to the printer
automatically cramming all of the optical data within the choosen
dimensions. At the enlargement size that you notice unacceptable blur,
you should stop and buy a better camera. Digital oversharpening is
never a pro quality solution beyond that optical limit, though it can
certainly is an oft used, low quality approach.
May 30, 2005 6:56:04 PM

Archived from groups: rec.photo.digital (More info?)

Tetractys wrote:


>
> Here is MS's version of the comment that Bayer filtering is
> responsible for the necessity of USM in the first place:
>
http://www.microsoft.com/windowsxp/using/digitalphotogr...


Wow you stepped right into it, here's where George explains that's why Bayer
filtering is such a bad thing...

--

Stacey
Anonymous
May 30, 2005 7:02:21 PM

Archived from groups: rec.photo.digital (More info?)

On 5/30/05 9:16 AM, in article
1117462598.038828.135100@g44g2000cwa.googlegroups.com,
"george_preddy@yahoo.com" <george_preddy@yahoo.com> wrote:

>
>
> Celtic Boar wrote:
>> Please take a look at the attached link. I am still trying to get the hang
>> of this Unsharp Mask Thing. Are these oversharpened.
>>
>> Canon 20D - Raw - 75-300 IS Zoom
>>
>> Thanks.
>
> I couldn't find any oringals there so there is no way to evaluate the
> images for sharpness. In general, if you are sharpening at all then
> you are oversharpening.
>
> Global digital sharpening tends to flatten or even invert the 3D nature
> of an image, since contrast is strengthened pixel by pixel, without
> regard to subject depth or the optics at play. The picture has to be
> really soft or taken OOF to get benefits of digital sharpening above
> the cost watermarking the image "from digital."
>
Considering your reputation in this group I hesitate to reply at all but for
the sake of potential newer dlsr users I can't let this statement stand!
Unless someone has optional in-camera sharpness cranked way up dlsr's are
noted for producing soft images - this is by the manufacturer's design.
Most all advanced amateurs and pros prefer it this way and will use some
sort of post processing program and either leave their images soft or
sharpen as desired. Many, many images benefit from sharpening and to say
that "In general, if you are sharpening at all then your are
oversharpening." is just plain wrong! As far as the rest of your statement
about sharpening tending to tending to "flatten" or "invert the 3D nature"
of an image - huh!
May 30, 2005 7:02:22 PM

Archived from groups: rec.photo.digital (More info?)

C Wright wrote:

> Many, many images benefit from sharpening and to say
> that "In general, if you are sharpening at all then your are
> oversharpening." is just plain wrong! As far as the rest of your
> statement about sharpening tending to tending to "flatten" or "invert the
> 3D nature" of an image - huh!


Ditto, george is clueless once again about anything related to photography,
nice post..

--

Stacey
Anonymous
May 30, 2005 7:57:09 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote:

> ... How could an 8MP recording not look
> horrid with only 2M pixels worth of actual
> full color optical data?

So "2M pixels worth of ... data" = "horrid."

And ...

> At 2MP, image quality is sharp, 3D, and life like.

You sure are a confused fellow, George.
Anonymous
May 30, 2005 8:27:08 PM

Archived from groups: rec.photo.digital (More info?)

Tetractys wrote:
> <george_preddy@yahoo.com> wrote:
>
> > ... How could an 8MP recording not look
> > horrid with only 2M pixels worth of actual
> > full color optical data?
>
> So "2M pixels worth of ... data" = "horrid."

At 8MP recorded, yes. 2MP isn't enough to support that, which is why
1DMkII images look so flat and blurry right out of camera. When
downsized to the sensor's actual RGB data gathering apability (2MP),
the images look great.
> And ...
>
> > At 2MP, image quality is sharp, 3D, and life like.
>
> You sure are a confused fellow, George.

You can see Foveon's 10.3MP clarity advantage over the 1DMkII here...

http://www.pbase.com/sharpness

Applying fake sharpening to a 2MP image recorded at 8MP is obviously
not the answer.
Anonymous
May 30, 2005 8:41:03 PM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> <george_preddy@yahoo.com> wrote in message
> news:1117486367.148808.280940@g49g2000cwa.googlegroups.com...
> SNIP
> > Like it or not, well focused Foveon images don't need sharpening
> > in post processing.
>
> Don't need? They wouldn't allow it, if you don't want to enhance
> aliasing artifacts.

Any optically sharp digital image will show the same degree of stair
stepping where there is a sharp edge. 10MP, 100MP, 1000000MP, it
doesn't matter--pixels are rectangular, not vectorized.

> > Why? Because the images are recorded at the sensor's
> > optical resolution--one dedicated RGB tiple for every RGB recorded
> > pixel.
>
> Nonsense, aliasing will add artifacts. Finer detail than the sensor
> can resolve will be imaged as larger detail, which cannot be undone
> after the fact.

Foveon doesn't have any such problem, because the image isn't upscaled
beyond it's optical resolution. Every dot in every image is optical.

> > Bayers record a 400% upscale by default, [...]
>
> Nonsense, again, as usual.

Only if you were fooled into thinking a 1DMkII has 8MP of full color
sensors. Most buyers, no doubt, were fooled like you. A 1DMkII only
is only 8MP-monochrome, not 8MP-full-color. That's why it isn't
competitive in terms of optical full color resolution with a
3.5MP-full-color Foveon image. See...

http://www.pbase.com/sharpness

But as I said 8MP-monochrome, 2MP-color, isn't all that bad. A sharp
8x10 is finally doable. Though 8MP-monochrome, assuming low noise and
decent 35mm optics, is the bare minimum Bayer I'd entertain.
Anonymous
May 30, 2005 11:26:28 PM

Archived from groups: rec.photo.digital (More info?)

Not at all.


"Celtic Boar" <extraneous@charter.net> wrote in message
news:p Usme.17445$cP2.6248@fe06.lga...
> Please take a look at the attached link. I am still trying to get the hang
> of this Unsharp Mask Thing. Are these oversharpened.
>
> Canon 20D - Raw - 75-300 IS Zoom
>
> Thanks.
>
> http://spaces.msn.com/members/fleetingglimpse/PersonalS...!1pioagCJB9TmXNBFRp_AlULA!741&_c=PhotoAlbum
>
> ~Rikk
>
> website: www.fleetingglimpse.com
> blog: http://spaces.msn.com/members/fleetingglmpse/
>
Anonymous
May 31, 2005 1:26:12 AM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> > Only if you were fooled into thinking a 1DMkII has 8MP of full color
> > sensors.
>
> But then you should know it, I assume/hope/doubt.
> Upscaling has nothing, nada, zip, to do with it.

Except that there is only 2MP of full color information in the 8MP
recording.

> > A 1DMkII only is only 8MP-monochrome, not 8MP-full-color.
>
> Do you understand the difference between monochrome and a spectral
> band? Apparently not.

Bayer sensors are all strictly monochrome. A color has to be
interpolated by digitally overlaying many monochrome photosites.

> > That's why it isn't competitive in terms of optical full color
> > resolution with a 3.5MP-full-color Foveon image. See...
> >
> > http://www.pbase.com/sharpness
>
> Why is the "Original 1D Mk II crop, as shot" the same size as the
> "Downsized..." version?

It's not. Duh.
Anonymous
May 31, 2005 3:03:01 AM

Archived from groups: rec.photo.digital (More info?)

On 5/30/05 3:42 PM, in article
1117485741.612985.156090@o13g2000cwo.googlegroups.com,
"george_preddy@yahoo.com" <george_preddy@yahoo.com> wrote:


>
> My point stands. Digital sharpening ruins images because it plows
> through every pixel blindly, instead of leaving sharpness/blur to
> optics. That is why film lovers hate digital, the result is flat and
> lifeless, often even inverted.
>
> If you sharpnen digitally, you are simply exceeding the capabilites of
> your camera at the expense of quality. The only proper way to handle
> digital images that are breaking down is to print them at the size they
> were intended. There are no acceptable algorithmic crutches that can
> substitute for sensor count.
>
George (if that is your name) you are a piece of work! Any digital
sharpening that I have done does not plow through every pixel blindly.
Sharpening that I am familiar with is adjustable according to threshold,
radius and degree or amount. Millions of images taken by thousands of
digital photographers, and sharpened digitally, disprove your assertion that
they are all exceeding the capabilities of their cameras at the expense of
quality. Of course there are some flat and lifeless digital images out
there but, there were/are an equal degree of flat and lifeless film images
as well!
Anonymous
May 31, 2005 4:21:41 AM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117486367.148808.280940@g49g2000cwa.googlegroups.com...
SNIP
> Like it or not, well focused Foveon images don't need sharpening
> in post processing.

Don't need? They wouldn't allow it, if you don't want to enhance
aliasing artifacts.

> Why? Because the images are recorded at the sensor's
> optical resolution--one dedicated RGB tiple for every RGB recorded
> pixel.

Nonsense, aliasing will add artifacts. Finer detail than the sensor
can resolve will be imaged as larger detail, which cannot be undone
after the fact.

> Bayers record a 400% upscale by default, [...]

Nonsense, again, as usual.

> My 1DMkII, for example, is a 2MP camera.

Nonsense, again, as usual.

Bart
Anonymous
May 31, 2005 8:18:04 AM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117496463.294846.290480@g14g2000cwa.googlegroups.com...
>
>
> Bart van der Wolf wrote:
>> <george_preddy@yahoo.com> wrote in message
>> news:1117486367.148808.280940@g49g2000cwa.googlegroups.com...
SNIP
>> > Bayers record a 400% upscale by default, [...]
>>
>> Nonsense, again, as usual.
>
> Only if you were fooled into thinking a 1DMkII has 8MP of full color
> sensors.

But then you should know it, I assume/hope/doubt.
Upscaling has nothing, nada, zip, to do with it.

Like in any Bayer pattern filtered sensor array, each sensel captures
roughly 1/3rd of the human visible spectrum, due to color filters on
each sensel. Demosaicing interpolates 2/3rd of the chromaticity from
the contribution from several neighboring sensels, and complements the
luminocity.

> Most buyers, no doubt, were fooled like you.

And you base that assertion on ... personal experience?

> A 1DMkII only is only 8MP-monochrome, not 8MP-full-color.

Do you understand the difference between monochrome and a spectral
band? Apparently not.

> That's why it isn't competitive in terms of optical full color
> resolution with a 3.5MP-full-color Foveon image. See...
>
> http://www.pbase.com/sharpness

Why is the "Original 1D Mk II crop, as shot" the same size as the
"Downsized..." version?
More snake-oil from Steve Giovenella? Are you trying (in vain as
usual) to pull a preddy?

Bart
Anonymous
May 31, 2005 5:09:43 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117513572.872817.98990@g44g2000cwa.googlegroups.com...
>
>
> Bart van der Wolf wrote:
SNIP
>> Do you understand the difference between monochrome and
>>a spectral band? Apparently not.
>
> Bayer sensors are all strictly monochrome.

Which again proves my point, you seem clueless.

Bart
Anonymous
May 31, 2005 11:58:16 PM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> <george_preddy@yahoo.com> wrote in message
> news:1117513572.872817.98990@g44g2000cwa.googlegroups.com...
> >
> >
> > Bart van der Wolf wrote:
> SNIP
> >> Do you understand the difference between monochrome and
> >>a spectral band? Apparently not.
> >
> > Bayer sensors are all strictly monochrome.
>
> Which again proves my point, you seem clueless.

But you really are. You learned something today.

When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M full
color pixels. I can't believe you didn't know that.
Anonymous
June 1, 2005 4:20:16 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117594696.335653.87000@z14g2000cwz.googlegroups.com...
>
>
> Bart van der Wolf wrote:
>> <george_preddy@yahoo.com> wrote in message
>> news:1117513572.872817.98990@g44g2000cwa.googlegroups.com...
>> >
>> >
>> > Bart van der Wolf wrote:
>> SNIP
>> >> Do you understand the difference between monochrome and
>> >>a spectral band? Apparently not.
>> >
>> > Bayer sensors are all strictly monochrome.
>>
>> Which again proves my point, you seem clueless.
>
> But you really are. You learned something today.
>
> When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M
> full
> color pixels. I can't believe you didn't know that.

It was already clear that you don't understand the difference between
monochrome (single color), and spectral band. Each sensel is natively
sensitive to a spectrum of roughly 350 to 1000 nm, and filters
restrict that to 3 (sometimes 4) slightly overlapping spectral bands.

Bart
Anonymous
June 2, 2005 1:34:40 AM

Archived from groups: rec.photo.digital (More info?)

JPS@no.komm wrote:
> In message <1117594696.335653.87000@z14g2000cwz.googlegroups.com>,
> george_preddy@yahoo.com wrote:
>
> >When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M full
> >color pixels.
>
> It means neither. It means that 8M samples are taken,

Bayer cameras all use a completely monochrome sensor, plain old
greyscale. There is no possible way for it to take a sample that is
not a monochrome sample.

> There is absolutely no reason why the three color samples have to be
> taken at the same 2D location.

Exactly. There is no resolution difference, whatsoever, based the
method you choose to take the 3 required RGB exposures to get a
composite color pixel.

You can employ 3 complete sensors, simultaneously, like Foveon and the
other 3-CCD/CMOS cameras do, or you can triple pump a single sensor 3
times in rapid succession behind a changing color wheel filter, or you
can use a mosiac filter to sub-divide 1 sensor into 3 very small RGB
exposures that are all snapped simultaneously.

In all cases, the resulting composite full color resolution is equal to
the size of an individual color channel, it IS NOT EQUAL to all three
monochrome exposures added together.

Obviously.
Anonymous
June 2, 2005 1:46:26 AM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> <george_preddy@yahoo.com> wrote in message

> > When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M
> > full color pixels. I can't believe you didn't know that.
>
> It was already clear that you don't understand the difference between
> monochrome (single color), and spectral band. Each sensel is natively
> sensitive to a spectrum of roughly 350 to 1000 nm, and filters
> restrict that to 3 (sometimes 4) slightly overlapping spectral bands.

Bayer cameras use grayscale sensors. Thus there is no possible way for
a Bayer camera to take a pixel sample that is not grayscale. A color
mosiac filter is used to subdivide that monochrome device in to 3 very
small, still monochrome, devices.

Any resulting composite color image resolution is equal to the size of
the sub-divisions superimposed on top of one another, NOT EQUAL to the
3 monochrome RGB exposures all laid side by side. Obviously.
Anonymous
June 2, 2005 5:29:30 AM

Archived from groups: rec.photo.digital (More info?)

In message <1117594696.335653.87000@z14g2000cwz.googlegroups.com>,
george_preddy@yahoo.com wrote:

>When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M full
>color pixels.

It means neither. It means that 8M samples are taken, in three
different color bands, at a total of 8M 2D locations. This is not as
accurate as taking 24M samples in 8M 2D locations, but is much more
detailed than taking 8M samples in 2.66M 2D locations.

There is absolutely no reason why the three color samples have to be
taken at the same 2D location.

--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
June 2, 2005 2:16:11 PM

Archived from groups: rec.photo.digital (More info?)

JPS@no.komm wrote:

>george_preddy@yahoo.com wrote:
>>When a Bayer camera says "8MP" that means "8MP MONOCHROME", not 8M full
>>color pixels.
>
>It means neither. It means that 8M samples are taken, in three
>different color bands, at a total of 8M 2D locations. This is not as
>accurate as taking 24M samples in 8M 2D locations, but is much more
>detailed than taking 8M samples in 2.66M 2D locations.
>
>There is absolutely no reason why the three color samples have to be
>taken at the same 2D location.

In fact, one should consider the characteristics of typical images
to see which technique is best. In standard images, colours
changes gradually or at sharp edges, not in random 1 pixel patterns.
That means the interpolation provided by the Bayer filter will give
better resolution and more information where it's needed. It's
similar to things like image compression applying to typical images
but being useless on completely random noise patterns.

This "George Preddy" seems utterly desperate to rationalise his
purchase of a foveon sensor camera. He'd probably expend less
energy pulling his hair out if he just dumps it now and gets a
standard one before it's too late. But then again, he might be
the type who still drives a wankel engine car.

--
Ken Tough
Anonymous
June 2, 2005 4:14:19 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117686880.656488.193940@g14g2000cwa.googlegroups.com...
SNIP
> Bayer cameras all use a completely monochrome sensor, plain old
> greyscale.

Wow, if only you knew how twisted your use of terminology is. What's
worse, it is not only deliberate (in an attempt to provoke a/any
reaction), but it also shows that you really don't understand it.

Look it up; Monochrome, achromatic, grayscale/greyscale, spectral
band, you might learn something. It might even improve the quality of
your trolling attempts, which are quite poor sofar.

Bart
Anonymous
June 2, 2005 4:56:50 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117687586.304517.15900@o13g2000cwo.googlegroups.com...
SNIP
> Bayer cameras use grayscale sensors. Thus there is no possible
> way for a Bayer camera to take a pixel sample that is not grayscale.

Wrong, again, as usual.

Sensors measure luminance (by integrating photon energy striking the
sensor during the exposure time). A single sensor cannot represent
more than a single luminance level. By using a spectral bandpass
filter, one can integrate the luminance of the spectral band's
contribution, rather than full spectrum. Three (sometimes 4) of such
(slightly overlapping) spectral ranges are captured in a sensor array,
and used to interpolate colors in a tri-chromatic color model (a
capture process somewhat similar to how the human eye discriminates
color).

The individual spectral range samples in a Bayer CFA are taken from
neigboring physical locations in the 2D sensor array (similar to the
cones in the human retina), and the results are used to reconstruct
tri-chromatic color at all resulting sampling locations (so 2/3rd of
the resulting pixel color is calculated from neighboring sensor data).
Luminance is calculated from each of the individual luminance samples,
augmented by the data from surrounding sample positions, which leads
to very little loss of accuracy.

Bart
Anonymous
June 3, 2005 1:31:20 AM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> <george_preddy@yahoo.com> wrote in message
> news:1117687586.304517.15900@o13g2000cwo.googlegroups.com...
> SNIP
> > Bayer cameras use grayscale sensors. Thus there is no possible
> > way for a Bayer camera to take a pixel sample that is not grayscale.
>
> Wrong, again, as usual.

All Bayer sensors are strictly monochrome devices. There are no
exceptions.
Anonymous
June 3, 2005 1:38:16 AM

Archived from groups: rec.photo.digital (More info?)

In message <1117687586.304517.15900@o13g2000cwo.googlegroups.com>,
george_preddy@yahoo.com wrote:

>Bayer cameras use grayscale sensors.

The bottom layer, the actual sensor, is panchromatic, but each sensel
has a color filter above it, so it is effectively not greyscale.

>Thus there is no possible way for
>a Bayer camera to take a pixel sample that is not grayscale. A color
>mosiac filter is used to subdivide that monochrome device in to 3 very
>small, still monochrome, devices.

They are not monochrome (panchromatic) once the filters are placed over
them.

>Any resulting composite color image resolution is equal to the size of
>the sub-divisions superimposed on top of one another, NOT EQUAL to the
>3 monochrome RGB exposures all laid side by side. Obviously.

Obviously not. This is what you want to be true, but it is not.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
June 3, 2005 1:50:03 AM

Archived from groups: rec.photo.digital (More info?)

Bart van der Wolf wrote:
> <george_preddy@yahoo.com> wrote in message
> news:1117686880.656488.193940@g14g2000cwa.googlegroups.com...
> SNIP
> > Bayer cameras all use a completely monochrome sensor, plain old
> > greyscale.
>
> Wow, if only you knew how twisted your use of terminology is. What's
> worse, it is not only deliberate (in an attempt to provoke a/any
> reaction), but it also shows that you really don't understand it.
>
> Look it up; Monochrome, achromatic, grayscale/greyscale, spectral
> band, you might learn something. It might even improve the quality of
> your trolling attempts, which are quite poor sofar.

Ok, here it is all looked up for you...
http://photonotes.org/cgi-bin/entry.pl?id=Imagesensor

Take special note of the parts about all Bayer sensors being strictly
monochrome devices and Foveon's being the only full color CMOS, thus
eliminating the need for color interpolation.
Anonymous
June 3, 2005 5:40:52 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117773079.862782.301770@g43g2000cwa.googlegroups.com...
>
>
> Bart van der Wolf wrote:
>> <george_preddy@yahoo.com> wrote in message
>> news:1117687586.304517.15900@o13g2000cwo.googlegroups.com...
>> SNIP
>> > Bayer cameras use grayscale sensors. Thus there is no possible
>> > way for a Bayer camera to take a pixel sample that is not
>> > grayscale.
>>
>> Wrong, again, as usual.
>
> All Bayer sensors are strictly monochrome devices. There are no
> exceptions.

Yawn, you are wrong, again, as usual.

Unless you can explain why they can produce color output if they are
strictly single color (mono chrome) devices.

Bart
Anonymous
June 3, 2005 5:40:53 PM

Archived from groups: rec.photo.digital (More info?)

On Fri, 3 Jun 2005 13:40:52 +0200, "Bart van der Wolf"
<bvdwolf@no.spam> wrote:


>Unless you can explain why they can produce color output if they are
>strictly single color (mono chrome) devices.


The real question, Bart, is why you continue
to engage the preddy-troll. You should know
better.


rafe b.
http://www.terrapinphoto.com
Anonymous
June 3, 2005 5:52:53 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117773670.514681.113260@z14g2000cwz.googlegroups.com...
>
>
> J...@no.komm wrote:
>> In message <1117687586.304517.15900@o13g2000cwo.googlegroups.com>,
>> george_preddy@yahoo.com wrote:
>>
>> >Bayer cameras use grayscale sensors.
>>
>> The bottom layer, the actual sensor, is panchromatic, but each
>> sensel has a color filter above it, so it is effectively not
>> greyscale.
>
> It is still monochrome. You can control what photons hit the
> cheap Bayer grayscle sensor with a mosiac filter, but you still
> have a purely grayscale device.

Terminology abuse warning : Monochrome is not Grayscale.
Language comprehension warning: A sensor is sensitive to a broad
spectrum of electromagnetic radiation, not a single (mono) wavelength.

> Using a mosaic filter takes that nice and inexpensive grayscale
> sensor and divides it into 3 tiny RGB sub-sections which are
> combined to form a color image.

Wrong, again, as usual. They are not combined, the sensors record
(filtered) luminance that is unique for the sensor's location in a
sensor array.

Bart
Anonymous
June 3, 2005 5:52:54 PM

Archived from groups: rec.photo.digital (More info?)

On Fri, 3 Jun 2005 13:52:53 +0200, "Bart van der Wolf"
<bvdwolf@no.spam> wrote:

>
><george_preddy@yahoo.com> wrote in message
>news:1117773670.514681.113260@z14g2000cwz.googlegroups.com...
>
>> Using a mosaic filter takes that nice and inexpensive grayscale
>> sensor and divides it into 3 tiny RGB sub-sections which are
>> combined to form a color image.
>
>Wrong, again, as usual. They are not combined, the sensors record
>(filtered) luminance that is unique for the sensor's location in a
>sensor array.

Indeed, also anyone who spent 3 seconds looking at a diagram of a
bayer sensor would know there are *four* unique color sensitive
photo-sites for each pixel, not three. Typically one red, one blue and
two greens - although there is no reason why they couldn't change this
to some other combination in the future.

--
Owamanga!
http://www.pbase.com/owamanga
Anonymous
June 3, 2005 7:23:25 PM

Archived from groups: rec.photo.digital (More info?)

<george_preddy@yahoo.com> wrote in message
news:1117774203.294268.191050@o13g2000cwo.googlegroups.com...
>
>
> Bart van der Wolf wrote:
>> <george_preddy@yahoo.com> wrote in message
>> news:1117686880.656488.193940@g14g2000cwa.googlegroups.com...
>> SNIP
>> > Bayer cameras all use a completely monochrome sensor, plain old
>> > greyscale.
>>
>> Wow, if only you knew how twisted your use of terminology is.
>> What's
>> worse, it is not only deliberate (in an attempt to provoke a/any
>> reaction), but it also shows that you really don't understand it.
>>
>> Look it up; Monochrome, achromatic, grayscale/greyscale, spectral
>> band, you might learn something. It might even improve the quality
>> of
>> your trolling attempts, which are quite poor sofar.
>
> Ok, here it is all looked up for you...
> http://photonotes.org/cgi-bin/entry.pl?id=Imagesensor
>
> Take special note of the parts about all Bayer sensors being
> strictly
> monochrome devices and Foveon's being the only full color CMOS, thus
> eliminating the need for color interpolation.

If that's the source and extent of your knowledge, it explains
something (but then ignorance is bliss, as long as you keep it to
yourself).

For the readers that are capable of learning:
http://www.photonics.com/dictionary/
is a much better site for translation of terms, and for search-word
collection.
For instance
<http://www.photonics.com/dictionary/lookup/XQ/ASP/url.l...;

Bart
Anonymous
June 3, 2005 8:28:29 PM

Archived from groups: rec.photo.digital (More info?)

"rafe bustin" <rafe b at speakeasy dot net> wrote in message
news:9qh0a1h4kavqr92eht77rq87219bbbd37h@4ax.com...
> On Fri, 3 Jun 2005 13:40:52 +0200, "Bart van der Wolf"
> <bvdwolf@no.spam> wrote:
>
>
>>Unless you can explain why they can produce color output if they are
>>strictly single color (mono chrome) devices.
>
>
> The real question, Bart, is why you continue
> to engage the preddy-troll. You should know
> better.

Why? Pretty simple, because he won't go away.
So, might as well correct his misinformation, before newbies get
confused.

Bart
Anonymous
June 3, 2005 9:46:10 PM

Archived from groups: rec.photo.digital (More info?)

"Owamanga" <owamanga(not-this-bit)@hotmail.com> wrote in message
news:f7m0a15tta31ood6im8r40343qiu4durnn@4ax.com...
> On Fri, 3 Jun 2005 13:52:53 +0200, "Bart van der Wolf"
> <bvdwolf@no.spam> wrote:
>
>>
>><george_preddy@yahoo.com> wrote in message
>>news:1117773670.514681.113260@z14g2000cwz.googlegroups.com...
>>
>>> Using a mosaic filter takes that nice and inexpensive grayscale
>>> sensor and divides it into 3 tiny RGB sub-sections which are
>>> combined to form a color image.
>>
>>Wrong, again, as usual. They are not combined, the sensors record
>>(filtered) luminance that is unique for the sensor's location in a
>>sensor array.
>
> Indeed, also anyone who spent 3 seconds looking at a diagram of a
> bayer sensor would know there are *four* unique color sensitive
> photo-sites for each pixel, not three.

Not really for each pixel. Try
<http://www.fillfactory.com/htm/technology/htm/rgbfaq.ht...; , and go
the the section (a little further than 2/3rd down the page) called
"reconstruction algorithms".
Many different methods with different trade-offs can be used e.g.
<http://www-ise.stanford.edu/~tingchen/main.htm&gt;,
<http://home.comcast.net/~rramanath/Research/demosaickin...;
, and many more.

It boils down to complementing the filtered signal with a
reconstruction of the missing data from many neighboring photosites,
so each RGB output pixel will be partly actual data and partly
reconstructed data, *for each and every sampling position*.

There is absolutely *no* 'combination' of R+G+B(+G) pixel blocks
taking place in regular demosaicing, because that would lose lots of
resolution (which is what preddy wants to preach, to annoy).

Bart
Anonymous
June 3, 2005 9:46:11 PM

Archived from groups: rec.photo.digital (More info?)

On Fri, 3 Jun 2005 17:46:10 +0200, "Bart van der Wolf"
<bvdwolf@no.spam> wrote:

>> Indeed, also anyone who spent 3 seconds looking at a diagram of a
>> bayer sensor would know there are *four* unique color sensitive
>> photo-sites for each pixel, not three.
>
>Not really for each pixel.

Sorry, I should have said for each 'preddy pixel'...

--
Owamanga!
http://www.pbase.com/owamanga
Anonymous
June 3, 2005 10:12:40 PM

Archived from groups: rec.photo.digital (More info?)

"Owamanga" <owamanga(not-this-bit)@hotmail.com> wrote in message
news:lbv0a1h2tpff1hrqvsf4uft5jpvgq7gu9h@4ax.com...
> On Fri, 3 Jun 2005 17:46:10 +0200, "Bart van der Wolf"
> <bvdwolf@no.spam> wrote:
>
>>> Indeed, also anyone who spent 3 seconds looking at a diagram of a
>>> bayer sensor would know there are *four* unique color sensitive
>>> photo-sites for each pixel, not three.
>>
>>Not really for each pixel.
>
> Sorry, I should have said for each 'preddy pixel'...

Agreed.

Bart
Anonymous
June 4, 2005 1:25:01 AM

Archived from groups: rec.photo.digital (More info?)

On Fri, 03 Jun 2005 13:18:35 GMT, Owamanga
<owamanga(not-this-bit)@hotmail.com> wrote:

>On Fri, 3 Jun 2005 13:52:53 +0200, "Bart van der Wolf"
><bvdwolf@no.spam> wrote:
>
>>
>><george_preddy@yahoo.com> wrote in message
>>news:1117773670.514681.113260@z14g2000cwz.googlegroups.com...
>>
>>> Using a mosaic filter takes that nice and inexpensive grayscale
>>> sensor and divides it into 3 tiny RGB sub-sections which are
>>> combined to form a color image.
>>
>>Wrong, again, as usual. They are not combined, the sensors record
>>(filtered) luminance that is unique for the sensor's location in a
>>sensor array.
>
>Indeed, also anyone who spent 3 seconds looking at a diagram of a
>bayer sensor would know there are *four* unique color sensitive
>photo-sites for each pixel, not three. Typically one red, one blue and
>two greens - although there is no reason why they couldn't change this
>to some other combination in the future.


Not exactly right. In *most* Bayer cells,
the two green sensors are identical. I believe
Sony has some sensors with two different greens.
(They refer to the 2nd green as "emerald.")


rafe b.
http://www.terrapinphoto.com
Anonymous
June 4, 2005 3:47:15 AM

Archived from groups: rec.photo.digital (More info?)

In message <1117773079.862782.301770@g43g2000cwa.googlegroups.com>,
george_preddy@yahoo.com wrote:

>All Bayer sensors are strictly monochrome devices. There are no
>exceptions.

There really is no such thing as a bayer sensor, idiot. The sensor used
*UNDER* a Bayer color filter array is panchromatic without the CFA. The
CFA and the sensor combined record three separate color bands, and most
of them separate them *much* better than the foveon sensor does.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
June 4, 2005 3:47:16 AM

Archived from groups: rec.photo.digital (More info?)

Paul Rubin <http://phr.cx@NOSPAM.invalid&gt; writes:
> There have been some web sites about how to remove the IR filter from
> a DSLR sensor, for purposes like astrophotography.
>
> Do you know if it's also usually possible to remove the Bayer sensor?

Bah, I meant Bayer filter. Preddy has rotted my brain.
Anonymous
June 4, 2005 3:47:16 AM

Archived from groups: rec.photo.digital (More info?)

JPS@no.komm writes:
> There really is no such thing as a bayer sensor, idiot. The sensor used
> *UNDER* a Bayer color filter array is panchromatic without the CFA. The
> CFA and the sensor combined record three separate color bands, and most
> of them separate them *much* better than the foveon sensor does.

There have been some web sites about how to remove the IR filter from
a DSLR sensor, for purposes like astrophotography.

Do you know if it's also usually possible to remove the Bayer sensor?
Anonymous
June 4, 2005 4:35:48 AM

Archived from groups: rec.photo.digital (More info?)

In message <1117773670.514681.113260@z14g2000cwz.googlegroups.com>,
george_preddy@yahoo.com wrote:

>You need 3 exposures (R+G+B) to form color pixels. No way around it.

No, that's what you need to get RGB pixel *samples*. You don't need
those, however, to form a color image. If you did, you couldn't say
that humans see color.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
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