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Matthew
January 16th 04, 10:32 PM
There is something aboutt CCDs that I need to understand. It is
in conjunction with Digital Cameras. Photography people who
are mostly familiar with film based may not be so with CCD
so let me ask the questions here.

One CCD has 5 megapixel capability with 9mm size.

Another CCD has 2 megapixel capability with 12.5mm size.

Using F2.8 lens. Is there evidence that the CCD with bigger
size sensor (that I presume in the 2megapixel/12.5mm combo)
is more sensitive to light such that using the same target at night
such as indoor object with flourescent light, it should produce
a brighter image using the same shutter speed of 1/30 secs and
iso rating for example??

Thanks.

Matt

Phil
January 17th 04, 12:16 AM
As far as I am aware no. The brightness of the resultant image is
dependant entirely on the iso setting. Yes the larger pixels will
collect more light, but the resultant charge will be amplified by a
smaller amount to obtain the required brightness levels as determined by
the iso setting.
What should improve is the signal to noise ratio. There has been a lot
of discussion on many camera forums recently about this subject, and the
general feeling is that when comparing cameras with similar chips but
different sizes, then the ones with larger pixels tend to give cleaner
images with less of the random noise that one can see particularly in
low light,long exposure images.
Phil Bishop

Matthew wrote:
> There is something aboutt CCDs that I need to understand. It is
> in conjunction with Digital Cameras. Photography people who
> are mostly familiar with film based may not be so with CCD
> so let me ask the questions here.
>
> One CCD has 5 megapixel capability with 9mm size.
>
> Another CCD has 2 megapixel capability with 12.5mm size.
>
> Using F2.8 lens. Is there evidence that the CCD with bigger
> size sensor (that I presume in the 2megapixel/12.5mm combo)
> is more sensitive to light such that using the same target at night
> such as indoor object with flourescent light, it should produce
> a brighter image using the same shutter speed of 1/30 secs and
> iso rating for example??
>
> Thanks.
>
> Matt

Matthew
January 17th 04, 07:26 AM
Phil > wrote in message >...
> As far as I am aware no. The brightness of the resultant image is
> dependant entirely on the iso setting. Yes the larger pixels will
> collect more light, but the resultant charge will be amplified by a
> smaller amount to obtain the required brightness levels as determined by
> the iso setting.
> What should improve is the signal to noise ratio. There has been a lot
> of discussion on many camera forums recently about this subject, and the
> general feeling is that when comparing cameras with similar chips but
> different sizes, then the ones with larger pixels tend to give cleaner
> images with less of the random noise that one can see particularly in
> low light,long exposure images.
> Phil Bishop

Hmm... supposed I want to take the shot of the moon (to be astronomy
related or other low light indoor object) using the hand and I have
to increase the shutter from the default 1 second exposure (as
set by an average digital camera such as the 9mm Sony P10) to 1/30 sec
or more to prevent blurred images from the hand shake with ISO both
fixed at 100. What design changes in the CCD can give a brighter image?
I'm evaluating what model can give a brighter image using similar ISO
setting. Or if you are right in your comment that it is dependent
entirely on ISO. In other words, you mean bigger CCD sensor can
produce higher ISO with cleaner image such that it can create clean
ISO 400 images compared to the ISO 100 using small CCD sensor? The
digital cameras of years past all use bigger CCDs as it was then
difficult to produce smaller ones. This means those cameras of years
past are of greater quality that those now and could produce higher
cleaner ISO image (?)

Matt



>
> Matthew wrote:
> > There is something aboutt CCDs that I need to understand. It is
> > in conjunction with Digital Cameras. Photography people who
> > are mostly familiar with film based may not be so with CCD
> > so let me ask the questions here.
> >
> > One CCD has 5 megapixel capability with 9mm size.
> >
> > Another CCD has 2 megapixel capability with 12.5mm size.
> >
> > Using F2.8 lens. Is there evidence that the CCD with bigger
> > size sensor (that I presume in the 2megapixel/12.5mm combo)
> > is more sensitive to light such that using the same target at night
> > such as indoor object with flourescent light, it should produce
> > a brighter image using the same shutter speed of 1/30 secs and
> > iso rating for example??
> >
> > Thanks.
> >
> > Matt

Phil
January 19th 04, 05:11 PM
While its true to say the older ccd's may have been bigger with bigger
pixels, you have to remember that there have been major advances in chip
construction and design. Newer ccd's require less power, so there is
less heat produced by the circuits (and heat is a major contribution to
noise,)and they tend to be more efficient, so the signal to noise ratio
is better.
Also, with consumer cameras (and I am most familiar with the Nikon
SLR's), a lot of effort has gone into the post capture processing
hardware and software. This means that the newer cameras are
considerably better than the older ones in terms of colour reproduction,
noise, and overal image quality.
Have a look at http://www.dpreview.com/ . Its the one camera review
site I've found which tests cameras from a technical rather than
subjective point.
Phil

Matthew wrote:

> Phil > wrote in message >...
>
>>As far as I am aware no. The brightness of the resultant image is
>>dependant entirely on the iso setting. Yes the larger pixels will
>>collect more light, but the resultant charge will be amplified by a
>>smaller amount to obtain the required brightness levels as determined by
>>the iso setting.
>>What should improve is the signal to noise ratio. There has been a lot
>>of discussion on many camera forums recently about this subject, and the
>>general feeling is that when comparing cameras with similar chips but
>>different sizes, then the ones with larger pixels tend to give cleaner
>>images with less of the random noise that one can see particularly in
>>low light,long exposure images.
>>Phil Bishop
>
>
> Hmm... supposed I want to take the shot of the moon (to be astronomy
> related or other low light indoor object) using the hand and I have
> to increase the shutter from the default 1 second exposure (as
> set by an average digital camera such as the 9mm Sony P10) to 1/30 sec
> or more to prevent blurred images from the hand shake with ISO both
> fixed at 100. What design changes in the CCD can give a brighter image?
> I'm evaluating what model can give a brighter image using similar ISO
> setting. Or if you are right in your comment that it is dependent
> entirely on ISO. In other words, you mean bigger CCD sensor can
> produce higher ISO with cleaner image such that it can create clean
> ISO 400 images compared to the ISO 100 using small CCD sensor? The
> digital cameras of years past all use bigger CCDs as it was then
> difficult to produce smaller ones. This means those cameras of years
> past are of greater quality that those now and could produce higher
> cleaner ISO image (?)
>
> Matt
>
>
>
>
>>Matthew wrote:
>>
>>>There is something aboutt CCDs that I need to understand. It is
>>>in conjunction with Digital Cameras. Photography people who
>>>are mostly familiar with film based may not be so with CCD
>>>so let me ask the questions here.
>>>
>>>One CCD has 5 megapixel capability with 9mm size.
>>>
>>>Another CCD has 2 megapixel capability with 12.5mm size.
>>>
>>>Using F2.8 lens. Is there evidence that the CCD with bigger
>>>size sensor (that I presume in the 2megapixel/12.5mm combo)
>>>is more sensitive to light such that using the same target at night
>>>such as indoor object with flourescent light, it should produce
>>>a brighter image using the same shutter speed of 1/30 secs and
>>>iso rating for example??
>>>
>>>Thanks.
>>>
>>>Matt