ISO / Noise / Megapixel

"Fco" <no DeleteThis @quierospam.com> wrote in message
news:fd7o6j$9rl$1@hefestos.uned.es...
>
> My Lumix FZ18 has an option called "Highest sensitivity". When I set this
> option, the maximun Megapixels accepted are 3.
>
> I do not understand very wee why?
>
> Does it mean that if I reduce the Megapixels the noise is also reduce?
>
> Thanks
> Paco

The way I would take this is that noise tends to be single pixels that are
not accurately reading or reporting a low level signal. By averaging several
adjacent pixels the apparent noise would tend to be minimized. But that
would mean that if you average several pixels, that group of pixels are
being stored as a single pixel. Thereby reducing the pixel count and
resolution of the final image. Just reducing the resolution by itself may
not reduce the noise, unless the averaging is also implemented. JMHO

Randy

==========
Randy Berbaum
Champaign, IL
 >> Stay informed about: ISO / Noise / Megapixel 

On Sep 24, 3:56 am, "Randy Berbaum" <rberb... DeleteThis @prairienet.org> wrote:
> "Fco" <n... DeleteThis @quierospam.com> wrote in message
>
> news:fd7o6j$9rl$1@hefestos.uned.es...
>
>
>
> > My Lumix FZ18 has an option called "Highest sensitivity". When I set this
> > option, the maximun Megapixels accepted are 3.
>
> > I do not understand very wee why?
>
> > Does it mean that if I reduce the Megapixels the noise is also reduce?
>
> > Thanks
> > Paco
>
> The way I would take this is that noise tends to be single pixels that are
> not accurately reading or reporting a low level signal. By averaging several
> adjacent pixels the apparent noise would tend to be minimized. But that
> would mean that if you average several pixels, that group of pixels are
> being stored as a single pixel. Thereby reducing the pixel count and
> resolution of the final image. Just reducing the resolution by itself may
> not reduce the noise, unless the averaging is also implemented. JMHO
>
> Randy
>
> ==========
> Randy Berbaum
> Champaign, IL

The noise reduction is by the square root of the number of pixels
averaged. Averaging four actual detector pixels for each pixel in the
final image improves SNR by a factor of two.
 >> Stay informed about: ISO / Noise / Megapixel 

Thanks for your clarification


"Randy Berbaum" <rberbaum.DeleteThis@prairienet.org> escribió en el mensaje
news:fd7u5g$oim$1@news.ks.uiuc.edu...
>
>
> "Fco" <no.DeleteThis@quierospam.com> wrote in message
> news:fd7o6j$9rl$1@hefestos.uned.es...
>>
>> My Lumix FZ18 has an option called "Highest sensitivity". When I set this
>> option, the maximun Megapixels accepted are 3.
>>
>> I do not understand very wee why?
>>
>> Does it mean that if I reduce the Megapixels the noise is also reduce?
>>
>> Thanks
>> Paco
>
> The way I would take this is that noise tends to be single pixels that are
> not accurately reading or reporting a low level signal. By averaging
> several adjacent pixels the apparent noise would tend to be minimized. But
> that would mean that if you average several pixels, that group of pixels
> are being stored as a single pixel. Thereby reducing the pixel count and
> resolution of the final image. Just reducing the resolution by itself may
> not reduce the noise, unless the averaging is also implemented. JMHO
>
> Randy
>
> ==========
> Randy Berbaum
> Champaign, IL
>
>
>
 >> Stay informed about: ISO / Noise / Megapixel 

thanks for the information,


I understand then that if I set my 8MP camera, to for example 2MP, the
noise algorithm probably will average 4pixels to create a single pixel. In
this case, I should improve the SNR by reducing the resolution.





Is that correct?





If it is correct, probably I`ll never use 8MP. I´d prefer setting 4MP if I
am not going to have large prints.


thanks


"Don Stauffer in Minnesota" <stauffer RemoveThis @usfamily.net> escribió en el mensaje
news:1190639997.436761.108530@g4g2000hsf.googlegroups.com...
> On Sep 24, 3:56 am, "Randy Berbaum" <rberb... RemoveThis @prairienet.org> wrote:
>> "Fco" <n... RemoveThis @quierospam.com> wrote in message
>>
>> news:fd7o6j$9rl$1@hefestos.uned.es...
>>
>>
>>
>> > My Lumix FZ18 has an option called "Highest sensitivity". When I set
>> > this
>> > option, the maximun Megapixels accepted are 3.
>>
>> > I do not understand very wee why?
>>
>> > Does it mean that if I reduce the Megapixels the noise is also reduce?
>>
>> > Thanks
>> > Paco
>>
>> The way I would take this is that noise tends to be single pixels that
>> are
>> not accurately reading or reporting a low level signal. By averaging
>> several
>> adjacent pixels the apparent noise would tend to be minimized. But that
>> would mean that if you average several pixels, that group of pixels are
>> being stored as a single pixel. Thereby reducing the pixel count and
>> resolution of the final image. Just reducing the resolution by itself may
>> not reduce the noise, unless the averaging is also implemented. JMHO
>>
>> Randy
>>
>> ==========
>> Randy Berbaum
>> Champaign, IL
>
> The noise reduction is by the square root of the number of pixels
> averaged. Averaging four actual detector pixels for each pixel in the
> final image improves SNR by a factor of two.
>
>
 >> Stay informed about: ISO / Noise / Megapixel 

Fco wrote:
>
> thanks for the information,
>
>
> I understand then that if I set my 8MP camera, to for example 2MP, the
> noise algorithm probably will average 4pixels to create a single pixel. In
> this case, I should improve the SNR by reducing the resolution.
>
>
>
>
>
> Is that correct?
Yes! That is correct.
>
>
>
>
>
> If it is correct, probably I`ll never use 8MP. I´d prefer setting 4MP if I
> am not going to have large prints.

Using 8MP is desirable if you have lots of light.
Both SNR and Resolution will be high. That is the best of both worlds.
In bright light, the image quality of an FZ18 can compete favorably with
SOME DSLRs.
Bob Williams
>
>
> thanks
>
>
> "Don Stauffer in Minnesota" <stauffer.TakeThisOut@usfamily.net> escribió en el mensaje
> news:1190639997.436761.108530@g4g2000hsf.googlegroups.com...
>> On Sep 24, 3:56 am, "Randy Berbaum" <rberb....TakeThisOut@prairienet.org> wrote:
>>> "Fco" <n....TakeThisOut@quierospam.com> wrote in message
>>>
>>> news:fd7o6j$9rl$1@hefestos.uned.es...
>>>
>>>
>>>
>>>> My Lumix FZ18 has an option called "Highest sensitivity". When I set
>>>> this
>>>> option, the maximun Megapixels accepted are 3.
>>>> I do not understand very wee why?
>>>> Does it mean that if I reduce the Megapixels the noise is also reduce?
>>>> Thanks
>>>> Paco
>>> The way I would take this is that noise tends to be single pixels that
>>> are
>>> not accurately reading or reporting a low level signal. By averaging
>>> several
>>> adjacent pixels the apparent noise would tend to be minimized. But that
>>> would mean that if you average several pixels, that group of pixels are
>>> being stored as a single pixel. Thereby reducing the pixel count and
>>> resolution of the final image. Just reducing the resolution by itself may
>>> not reduce the noise, unless the averaging is also implemented. JMHO
>>>
>>> Randy
>>>
>>> ==========
>>> Randy Berbaum
>>> Champaign, IL
>> The noise reduction is by the square root of the number of pixels
>> averaged. Averaging four actual detector pixels for each pixel in the
>> final image improves SNR by a factor of two.
>>
>>
>
>
>
 >> Stay informed about: ISO / Noise / Megapixel 

On Sep 25, 6:44 am, Chris Malcolm <c... RemoveThis @holyrood.ed.ac.uk> wrote:
> Fco <n... RemoveThis @quierospam.com> wrote:
>
> > thanks for the information,
> > I understand then that if I set my 8MP camera, to for example 2MP, the
> > noise algorithm probably will average 4pixels to create a single pixel. In
> > this case, I should improve the SNR by reducing the resolution.
> > Is that correct?
> > If it is correct, probably I`ll never use 8MP. I'd prefer setting 4MP if I
> > am not going to have large prints.
>
> But you can get the best of both worlds by doing the noise reduction
> averaging, if necessary, afterwards, in an image editor. Note that
> you can also reduce noise by averaging the colours into black and
> white.
>
> --
> Chris Malcolm c... RemoveThis @infirmatics.ed.ac.uk DoD #205
> IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
> [http://www.dai.ed.ac.uk/homes/cam/]

I concur. The averaging algorithm in the camera is likely to be quite
primitive. Good photo editors typically have a selection of
algorithms and adjustment of parameters for them. Gaussian blur is a
good example.
 >> Stay informed about: ISO / Noise / Megapixel 

Fco <no.DeleteThis@quierospam.com> wrote:
>
> thanks for the information,


> I understand then that if I set my 8MP camera, to for example 2MP, the
> noise algorithm probably will average 4pixels to create a single pixel. In
> this case, I should improve the SNR by reducing the resolution.


> Is that correct?

> If it is correct, probably I`ll never use 8MP. I'd prefer setting 4MP if I
> am not going to have large prints.

But you can get the best of both worlds by doing the noise reduction
averaging, if necessary, afterwards, in an image editor. Note that
you can also reduce noise by averaging the colours into black and
white.

--
Chris Malcolm cam.DeleteThis@infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
 >> Stay informed about: ISO / Noise / Megapixel 

Chris Malcolm wrote:
[]
> But you can get the best of both worlds by doing the noise reduction
> averaging, if necessary, afterwards, in an image editor. Note that
> you can also reduce noise by averaging the colours into black and
> white.

... and perhaps get a more dramatic effect as a result....

David
 >> Stay informed about: ISO / Noise / Megapixel 

Then may I understand that probably the algorithm do not work like I am
supposing. I´ve tested and the noise seems to be the same at 8Mp or a 2Mp.


"Don Stauffer in Minnesota" <stauffer.RemoveThis@usfamily.net> escribió en el mensaje
news:1190727439.656184.252260@19g2000hsx.googlegroups.com...
> On Sep 25, 6:44 am, Chris Malcolm <c....RemoveThis@holyrood.ed.ac.uk> wrote:
>> Fco <n....RemoveThis@quierospam.com> wrote:
>>
>> > thanks for the information,
>> > I understand then that if I set my 8MP camera, to for example 2MP, the
>> > noise algorithm probably will average 4pixels to create a single pixel.
>> > In
>> > this case, I should improve the SNR by reducing the resolution.
>> > Is that correct?
>> > If it is correct, probably I`ll never use 8MP. I'd prefer setting 4MP
>> > if I
>> > am not going to have large prints.
>>
>> But you can get the best of both worlds by doing the noise reduction
>> averaging, if necessary, afterwards, in an image editor. Note that
>> you can also reduce noise by averaging the colours into black and
>> white.
>>
>> --
>> Chris Malcolm c....RemoveThis@infirmatics.ed.ac.uk DoD #205
>> IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
>> [http://www.dai.ed.ac.uk/homes/cam/]
>
> I concur. The averaging algorithm in the camera is likely to be quite
> primitive. Good photo editors typically have a selection of
> algorithms and adjustment of parameters for them. Gaussian blur is a
> good example.
>
>
>
 >> Stay informed about: ISO / Noise / Megapixel 

On Sep 25, 8:56 am, "Fco" <n....RemoveThis@quierospam.com> wrote:
> Then may I understand that probably the algorithm do not work like I am
> supposing. I´ve tested and the noise seems to be the same at 8Mp or a 2Mp.
>

> > I concur. The averaging algorithm in the camera is likely to be quite
> > primitive. Good photo editors typically have a selection of
> > algorithms and adjustment of parameters for them. Gaussian blur is a
> > good example.

Which algorithm? Gaussian blur?
 >> Stay informed about: ISO / Noise / Megapixel 

On Mon, 24 Sep 2007 09:15:44 +0200, "Fco" <no.TakeThisOut@quierospam.com> wrote:

>
> My Lumix FZ18 has an option called "Highest sensitivity". When I set this
>option, the maximun Megapixels accepted are 3.
>
>I do not understand very wee why?
>
>Does it mean that if I reduce the Megapixels the noise is also reduce?
>
>Thanks
>Paco
>
>

This sounds like your camera is implementing what is normally called "pixel
binning". A sensor chip technique invented years ago for the astrophotography
crowd where obtaining the maximum light sensitivity was more important than
resolution at times. The signal from multiples of pixels is added up as one
pixel. In effect you are getting very large detection areas equivalent to
full-size sensor cameras.


On Tue, 25 Sep 2007 15:56:26 +0200, "Fco" <no.TakeThisOut@quierospam.com> wrote:

>
>Then may I understand that probably the algorithm do not work like I am
>supposing. I´ve tested and the noise seems to be the same at 8Mp or a 2Mp.
>

It sounds like you may not be using it in the right way. Just lowering the
resolution of your image size probably won't automatically engage the "Highest
Sensitivity" mode, but I've not read the manual nor do I have one of these
cameras to test it.

This is getting interesting. After seeing the moon shot performances from these
cameras that someone else posted, and now knowing they have pixel-binning (I
wish all cameras had this), I should download one of their manuals if possible
to see how they are implementing these features.

The FZ18 might just be the next great camera that will beat all DSLRs, as so
many P&S cameras are easily doing these days. From the moon shots alone it's
already clearly better than the top-of-the-line DSLRs using the most expensive
glass available.

Kudos to Panasonic for taking the lead once again by pushing the envelope and
doing what they all claimed couldn't be done.
 >> Stay informed about: ISO / Noise / Megapixel 

Fco <no.TakeThisOut@quierospam.com> wrote:

> "Don Stauffer in Minnesota" <stauffer.TakeThisOut@usfamily.net> escribi? en el mensaje
> news:1190727439.656184.252260@19g2000hsx.googlegroups.com...
>> On Sep 25, 6:44 am, Chris Malcolm <c....TakeThisOut@holyrood.ed.ac.uk> wrote:
>>> Fco <n....TakeThisOut@quierospam.com> wrote:
>>>
>>> > thanks for the information,
>>> > I understand then that if I set my 8MP camera, to for example 2MP, the
>>> > noise algorithm probably will average 4pixels to create a single pixel.
>>> > In
>>> > this case, I should improve the SNR by reducing the resolution.
>>> > Is that correct?
>>> > If it is correct, probably I`ll never use 8MP. I'd prefer setting 4MP
>>> > if I
>>> > am not going to have large prints.
>>>
>>> But you can get the best of both worlds by doing the noise reduction
>>> averaging, if necessary, afterwards, in an image editor. Note that
>>> you can also reduce noise by averaging the colours into black and
>>> white.

>> I concur. The averaging algorithm in the camera is likely to be quite
>> primitive. Good photo editors typically have a selection of
>> algorithms and adjustment of parameters for them. Gaussian blur is a
>> good example.

> Then may I understand that probably the algorithm do not work like I am
> supposing. I've tested and the noise seems to be the same at 8Mp or a 2Mp.

What algorithm have you tested? In any decent photo editor you'll get
noise reduction if you resample the image to create a new size based
on reduced pixels. I'd expect the same to be true of changing
quality/image pixel quantity in the camera, but it wouldn't surprise
me if some cameras used a cheaper faster method which didn't reduce
noise, since they're limited in processing power compared to a
computer.

You need to tell us what camera or what editor and what you did before
we can comment on the behaviour of the algorithm.

--
Chris Malcolm cam.TakeThisOut@infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
 >> Stay informed about: ISO / Noise / Megapixel 

Thanks for your reply

The camera is a Panasonic Lumix FZ18



"Chris Malcolm" <cam RemoveThis @holyrood.ed.ac.uk> escribió en el mensaje
news:5m500bFbrhqiU1@mid.individual.net...
> Fco <no RemoveThis @quierospam.com> wrote:
>
> > "Don Stauffer in Minnesota" <stauffer RemoveThis @usfamily.net> escribi? en el
mensaje
> > news:1190727439.656184.252260@19g2000hsx.googlegroups.com...
> >> On Sep 25, 6:44 am, Chris Malcolm <c... RemoveThis @holyrood.ed.ac.uk> wrote:
> >>> Fco <n... RemoveThis @quierospam.com> wrote:
> >>>
> >>> > thanks for the information,
> >>> > I understand then that if I set my 8MP camera, to for example 2MP,
the
> >>> > noise algorithm probably will average 4pixels to create a single
pixel.
> >>> > In
> >>> > this case, I should improve the SNR by reducing the resolution.
> >>> > Is that correct?
> >>> > If it is correct, probably I`ll never use 8MP. I'd prefer setting
4MP
> >>> > if I
> >>> > am not going to have large prints.
> >>>
> >>> But you can get the best of both worlds by doing the noise reduction
> >>> averaging, if necessary, afterwards, in an image editor. Note that
> >>> you can also reduce noise by averaging the colours into black and
> >>> white.
>
> >> I concur. The averaging algorithm in the camera is likely to be quite
> >> primitive. Good photo editors typically have a selection of
> >> algorithms and adjustment of parameters for them. Gaussian blur is a
> >> good example.
>
> > Then may I understand that probably the algorithm do not work like I am
> > supposing. I've tested and the noise seems to be the same at 8Mp or a
2Mp.
>
> What algorithm have you tested? In any decent photo editor you'll get
> noise reduction if you resample the image to create a new size based
> on reduced pixels. I'd expect the same to be true of changing
> quality/image pixel quantity in the camera, but it wouldn't surprise
> me if some cameras used a cheaper faster method which didn't reduce
> noise, since they're limited in processing power compared to a
> computer.
>
> You need to tell us what camera or what editor and what you did before
> we can comment on the behaviour of the algorithm.
>
> --
> Chris Malcolm cam RemoveThis @infirmatics.ed.ac.uk DoD #205
> IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
> [http://www.dai.ed.ac.uk/homes/cam/]
>
>
 >> Stay informed about: ISO / Noise / Megapixel