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Scott W wrote:
> An interesting idea. I really don't know if Leica is using a
> interference filter or a absorption filter, I kind of think maybe an
> absorption filter. The reason I am thinking this is Leica talked about
> wanting to use a thinner then normal filter, most likely because they
> have very little working distance on their lenses. They said they are
> using a 0.5 mm filter, the standard thickness is 1.0mm and whereas this
> would not matter for a interference filter it is not good for an
> absorption filter.
>
> Scott
>

Ah. So, there are two types of IR blocking filters: Absorption and
interference. It's not hard to see why interference filters would have
such a strong angle dependence, now that I think about it. And I take it
that absorption filters do not display such a strong effect. If so, then
maybe that is not the problem.

I was trying to find some kind of rational justification for them not
having a strong enough IR blocking filter. Hmm....

acl wrote:
> Scott W wrote:
> > An interesting idea. I really don't know if Leica is using a
> > interference filter or a absorption filter, I kind of think maybe an
> > absorption filter. The reason I am thinking this is Leica talked about
> > wanting to use a thinner then normal filter, most likely because they
> > have very little working distance on their lenses. They said they are
> > using a 0.5 mm filter, the standard thickness is 1.0mm and whereas this
> > would not matter for a interference filter it is not good for an
> > absorption filter.
> >
> > Scott
> >
>
> Ah. So, there are two types of IR blocking filters: Absorption and
> interference. It's not hard to see why interference filters would have
> such a strong angle dependence, now that I think about it. And I take it
> that absorption filters do not display such a strong effect. If so, then
> maybe that is not the problem.
>
> I was trying to find some kind of rational justification for them not
> having a strong enough IR blocking filter. Hmm....

Here is what Lieca has said regarding the IR filter

"The glass cover of the image sensor of the LEICA M8 is a combination
of the IR barrier filter and a specially coated protective glass. The
transmission in the red and infrared region of the spectrum can be
controlled by the layer thickness of this filter. In the case of the
Leica M8, which is a very compact system, the thickness of the filter,
0.5 mm has proved to be ideal. The short back focal length is the base
for the compactness and the high quality of the standard and wide-angle
lenses. However, the resulting oblique angle of the incident light on
the sensor requires special adaptations of the filter.

Absence of color fringing / Image Resolution
The extremely thin layer of the filter, 0.5 mm prevents color fringing
at the corners of an image. This phenomenon, which is also known as
astigmatism and is frequently encountered with digital SLR cameras, is
not a problem for the LEICA M8 because of the thin glass cover on the
image sensor. This feature, plus the particularly high imaging quality
of Leica M lenses, is the reason for the high corner-to-corner image
resolution."

Now when they talk about special adaptations it would seem they are
saying for their lenses a thicker filter would mess up the image
resolution, which could well be true. As best as I can figure they did
the retracing with a 1mm think cover glass and did not like what they
saw and so went for a thinner filter. This thinner filter does not seem
to be up to the job.

Scott



Scott

Scott W wrote:
>
> Now when they talk about special adaptations it would seem they are
> saying for their lenses a thicker filter would mess up the image
> resolution, which could well be true. As best as I can figure they did
> the retracing with a 1mm think cover glass and did not like what they
> saw and so went for a thinner filter. This thinner filter does not seem
> to be up to the job.
>

I see, you mean that it's an absorption filter but they had problems
with the thickness if it was thick enough to do its job, again because
of the angles of incidence probably. But couldn't they just use a
different kind of absorption filter that would have the desirable effect
with the .5mm (or whatever) thickness? I assume the absorption
characteristics come from adding impurities to the glass or something
like that (so do not affect the refracting index).

I mean, it's not as if they are constrained by cost here. Is it possible
that they simply could not get the right absorption strength with that
thickness?

acl wrote:
> Scott W wrote:
> >
> > Now when they talk about special adaptations it would seem they are
> > saying for their lenses a thicker filter would mess up the image
> > resolution, which could well be true. As best as I can figure they did
> > the retracing with a 1mm think cover glass and did not like what they
> > saw and so went for a thinner filter. This thinner filter does not seem
> > to be up to the job.
> >
>
> I see, you mean that it's an absorption filter but they had problems
> with the thickness if it was thick enough to do its job, again because
> of the angles of incidence probably. But couldn't they just use a
> different kind of absorption filter that would have the desirable effect
> with the .5mm (or whatever) thickness? I assume the absorption
> characteristics come from adding impurities to the glass or something
> like that (so do not affect the refracting index).
>
> I mean, it's not as if they are constrained by cost here. Is it possible
> that they simply could not get the right absorption strength with that
> thickness?

They may well be constrained by cost, a special filter melt may cost
more then they are willing to pay. And filters are a standard thickness
of 1mm. It is easier to cut a filter thinner then it is to get a
special glass made up but then you had a much weaker filter.

They may also have gone with a weaker absorbing filter glass to get
more light through in which case they could go to a more aggressive
filter glass and perhaps be ok. But even an aggressive filter glass
like BG18 gets pretty weak at .5 mm. At 1 mm it only passes 1% at
700nm, but at 0.5 mm that will go up to 10%.

The other thing I am not sure of is how far can Hoya or Schott push
their absorption, I have been through this before where we had a lens
what was not designed to work with a cover glass and wanted to get the
filter as thin as possible. In the end we redesigned the lens to work
with the 1mm thick filter.

Scott

David J. Littleboy wrote:
> "Mike Fields" <spam_me_not_mr.gadget2@comcastDOTnet> wrote:
> > And, after you find the bugs for them, they fix
> > the software and charge you for the "upgrade"
> > (which fixes many of the things that did not work
> > as advertised but introduced new ones ... Acronis
> > "True Image" anyone ?)
>
> I doesn't work that way: the problems with the M8 can't be fixed in
> software.
>
> When you figure out for Leica that Bayer CFA filters are transparent to IR
> (which everyoner knew all along), and you figure out for Leica that Bayer
> cameras desperately need a low-pass (AA) filter (which everyone knew all
> along; heck the Foveon fans have been banging that into our heads for years
> now (they're right about Bayer arrays needing AA filtering, they're wrong
> about Foveon or monochrome sensors not needing it)), you'll realize that you
> spent US$5000 for a camera that is physically defective and simply not
> repairable.
>
> One completely and totally buck-nekked US$5000 emperor.

So people are just now getting the IR blocking filters that they order
and these seem to be doing wonders for the images. This is sort of a
good news bad news thing. For those who really want to use the M8 they
now have a way to do so and have it take photos with the colors right.
The bad news is the comparisons with and without the filter show just
how bad the colors are without the added filter. Green trees turn
pretty yellow without the filter for instance. So it is clear that
this is not just a problem with some dark clothing but a problem that
every M8 owner is gong to need to address if they want their colors to
be close to right.

It is was me and I has an M8 and really wanted to use it I would buy
the needed filters in a heart beat, but also be pretty mad that this
was not disclosed up front. People will understand that a camera by
itself if not a whole system and that you need to buy other items to
make it work. If I buy the body only of a camera I know I will need at
least one lens and this does not bother me. If I know the camera does
not come with a memory card again no big deal. But what is a big deal
is if there is some rather expensive item I need and you don't tell
me up front that I need it.

So it will be interesting to see what Leica comes up with and how well
they take care of their customers. I would imagine that Leica and
Kodak are going back and forth right now on who is going to pay for the
fix.

It will also be interesting to see if Leica continues to make the M8
with the weak filter. If they had any sense they would offer in with
both the weak and normal filter.

The immediate problem that people are now running into is that the
supply of these filters seems very limited right now.

As for the AA filter I don't think Leica is going to do anything about
that. And after reading a number of posts from Leica fans it is clear
most are willing to put up with some pretty big flaws in the M8. Even
with the colors looking like total crap where were/are some who felt it
was no big problem since you can fix the colors in Photoshop.

Scott

Scott W wrote:
>
> Over the last few days it has become clear that the M8 has far too weak
> of an IR blocking filter. The problem is textiles that are dyed black
> often reflect a lot of IR, which the camera sees as both red and blue.
> The result is that many clothes that should be black photograph as
> magenta.
>
> In watching the Leica forums I find it interesting that a number of
> people are saying that this is not a problem since it is easy to change
> the colors in Photoshop. Now call me crazy but I would be more then a
> little upset if I paid $5,000 for a camera only to find out that I had
> to hand adjust colors in my photos. The problem is that you can't
> just do a global replace of black for magenta since the real world does
> have magenta in it.
>
> It will be interesting to see how this plays out over the next few
> days.
>
> Acott


Hello, Scott:

Totally unacceptable! That's the type of performance one would expect
of a lousy "keychain camera" (of which I own a few), but not from a
ridiculously-overpriced, status symbol of a digicam.

Why, my own, lowly Kodak models produce stunning and accurate colors.
Oh, hold on...the M8, itself, contains a Kodak sensor! What it probably
needs (even more than a better "IR blocking filter") is a Kodak "Color
Science" chip.

This tiny DSP (digital signal processor) would undoubtedly improve the
M8's image quality significantly, if not enough to justify the Leica's
exorbitant cost. <g>


Cordially,
John Turco <>

"John Turco" <> wrote:
>
> Why, my own, lowly Kodak models produce stunning and accurate colors.
> Oh, hold on...the M8, itself, contains a Kodak sensor!

But your Kodak camera uses a Sony sensor...

David J. Littleboy
Tokyo, Japan

"David J. Littleboy" wrote:
>
> "John Turco" <> wrote:
> >
> > Why, my own, lowly Kodak models produce stunning and accurate colors.
> > Oh, hold on...the M8, itself, contains a Kodak sensor!
>
> But your Kodak camera uses a Sony sensor...
>
> David J. Littleboy
> Tokyo, Japan


Hello, David:

It does? Not according to Kodak <http://www.kodak.com>, itself:

DX3900 Zoom Digital Camera - Frequently Asked Questions http://www.kodak.com/eknec/PageQueri..._requestid=265

"Question:
Are the Kodak EasyShare digital cameras affected by the Sony
charge-coupled device (CCD) issue?

Answer: Answer last updated:08-21-06
No, Kodak EasyShare digital cameras are not affected by the Sony
charge-coupled device (CCD) issue because they do not use the
sensors in question."

Perhaps (although, unlikely), you had the following, obscure device
in mind?

Kodak Dental Systems - KODAK 1000 Intraoral Video Camera
http://www.kodak.com/global/en/healt...ntlIndex.jhtml

"Intelligent Precision
The new KODAK 1000 Intraoral Video Camera, with its improved
ergonomics and image quality, is more than just a communications
tool. Equipped with the latest generation SONY high resolution
CCD, your images are clear and precise. The macro mode (x60) can
display details invisible to the naked eye."


Cordially,
John Turco <>

"John Turco" <> wrote:
> "David J. Littleboy" wrote:
>>
>> "John Turco" <> wrote:
>> >
>> > Why, my own, lowly Kodak models produce stunning and accurate colors.
>> > Oh, hold on...the M8, itself, contains a Kodak sensor!
>>
>> But your Kodak camera uses a Sony sensor...
>
>
> Hello, David:
>
> It does? Not according to Kodak <http://www.kodak.com>, itself:

That was a _particular_ Sony sensor that had a problem. Read the fine print
carefully<g>.

"We cannot disclose which manufacturer's sensors we use in our digital
cameras. The Sony charge-coupled device (CCD) issue does not affect Kodak
digital cameras."

(Kodak _might_ not be using Sony sensors, but it's exceedingly unlikely. The
two other main CCD mfrs (Panasonic and Fuji) don't appear to be selling this
class of sensor. I think.)

David J. Littleboy
Tokyo, Japan


>
> DX3900 Zoom Digital Camera - Frequently Asked Questions
> http://www.kodak.com/eknec/PageQueri..._requestid=265
>
> "Question:
> Are the Kodak EasyShare digital cameras affected by the Sony
> charge-coupled device (CCD) issue?
>
> Answer: Answer last updated:08-21-06
> No, Kodak EasyShare digital cameras are not affected by the Sony
> charge-coupled device (CCD) issue because they do not use the
> sensors in question."
>
> Perhaps (although, unlikely), you had the following, obscure device
> in mind?
>
> Kodak Dental Systems - KODAK 1000 Intraoral Video Camera
> http://www.kodak.com/global/en/healt...ntlIndex.jhtml
>
> "Intelligent Precision
> The new KODAK 1000 Intraoral Video Camera, with its improved
> ergonomics and image quality, is more than just a communications
> tool. Equipped with the latest generation SONY high resolution
> CCD, your images are clear and precise. The macro mode (x60) can
> display details invisible to the naked eye."
>
>
> Cordially,
> John Turco <>

John Turco wrote:
[]
> Hello, Scott:
>
> Totally unacceptable! That's the type of performance one would expect
> of a lousy "keychain camera" (of which I own a few), but not from a
> ridiculously-overpriced, status symbol of a digicam.
>
> Why, my own, lowly Kodak models produce stunning and accurate colors.
> Oh, hold on...the M8, itself, contains a Kodak sensor! What it
> probably needs (even more than a better "IR blocking filter") is a
> Kodak "Color Science" chip.
>
> This tiny DSP (digital signal processor) would undoubtedly improve the
> M8's image quality significantly, if not enough to justify the Leica's
> exorbitant cost. <g>
>
>
> Cordially,
> John Turco <>

How is a DSP going to distinguish between IR and other energy illuminating
the sensor?

David