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Megapixels to Sensor Sizes - Best Matches?

 
 
Paul D. Sullivan
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      02-07-2007
I read an article on Cnet about how 8 or 10 megapixel cameras are
not as good as they could be because their megapixel capability
does not match sensor sizes well. If you buy a camera with 8 or
10 megapixels and they have some really small sensor, the extra
megapixels will not be realized in terms of quality.

Got me thinking - what are some of the best matches of megapixel
capability to sensor size?

How does the Canon a640 mentioned in the article hold up?

How does the Canon S3 IS hold up?

Olympus Evolt series with those 4/3rds sized sensors?

Do Fuji, Kodak, Nikon and others have a good ratio on average, or
are certain models better than others?

I'd like to think that consumers aren't getting screwed when they
want to get to an 8 or 10 megapixel camera, and wanted to ask
some of ya'all here about it so I could learn what up.

Any helpful answers would be appreciated.

Thanks


 
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skip
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      02-07-2007

"Paul D. Sullivan" <(E-Mail Removed)> wrote in message
newsDlyh.9047$xu4.4693@trndny04...

<snip>

>I read an article on Cnet about how 8 or 10 megapixel cameras are not as
>good as they could be because their megapixel capability does not match
>sensor sizes well. If you buy a camera with 8 or 10 megapixels and they
>have some really small sensor, the extra megapixels will not be realized in
>terms of quality.
>
> Got me thinking - what are some of the best matches of megapixel
> capability to sensor size?


<snip>

> How does the Canon S3 IS hold up?
>


To my eye the Canon S2 IS (one of which I own) with 5 Megapixels is less
noisy than its S3 successor with 6 Megapixels.

You can judge for yourself by looking at a side by side comparison here:

http://www.dpreview.com/reviews/canons3is/page6.asp

My personal and highly unscientific take on this is that 4 Megapixels is
about optimal for the small sensor point and shoot cameras I've used. I've
made sharp 8x10 Prints from images taken with a 2 Megapixel Nikon 950 on a
tripod.

The opinions of others are likely to vary.


 
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Roger N. Clark (change username to rnclark)
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      02-08-2007
Paul D. Sullivan wrote:
> I read an article on Cnet about how 8 or 10 megapixel cameras are
> not as good as they could be because their megapixel capability
> does not match sensor sizes well. If you buy a camera with 8 or
> 10 megapixels and they have some really small sensor, the extra
> megapixels will not be realized in terms of quality.
>
> Got me thinking - what are some of the best matches of megapixel
> capability to sensor size?


While one can't prove there is an optimum, because the
trade space of size of a pixel versus performance just keeps
getting better with larger pixels, I personally think the
about 6 to 8 micron pixel pitch is the ideal size. That pitch
allows many pixels to be crammed into an small sensor
(e.g. about 8 megapixels in APS-C), while still collecting
enough photons for great performance, including high ISO
performance. Collecting about 50,000 photons per pixel
produces beautiful images, and the 6 to 6 micron pixel pitches
do that. This is the performance point of many DSLRs.

Quantitative data on sensor performance can be found at:
http://www.clarkvision.com/imagedeta...rmance.summary
>
> How does the Canon a640 mentioned in the article hold up?
>
> How does the Canon S3 IS hold up?


S3: 2-micron pixel pith: performance near the bottom of the range on the
plots on the above page.
>
> Olympus Evolt series with those 4/3rds sized sensors?


E300: 5.3 micron pitch should plot in the mid range of performance:
below most DSLRs and above most P&S.
>
> Do Fuji, Kodak, Nikon and others have a good ratio on average, or
> are certain models better than others?


Look at each model. The newer P&S cameras seem to cram in megapixels,
and performance per pixel suffers. Most notably, the high iso
performance (Figures 6 and 7 on the above web page).
>
> I'd like to think that consumers aren't getting screwed when they
> want to get to an 8 or 10 megapixel camera, and wanted to ask
> some of ya'all here about it so I could learn what up.
>
> Any helpful answers would be appreciated.
>
> Thanks


Manufacturers are trying to hide the noise and low performance
issues by average pixel in their noise reduction software. So what any
one camera produces out of camera can be confusing and the
manufacturers are trying to get you to think they have a better
solution. But CCD and CMOS sensors have noise dominated by photon
counting statistics over most of their range. That is a fundamental
limit, so collecting more photons with larger pixels is the only
major performance metric.

Other related info at:
http://www.clarkvision.com/imagedeta...ensor_analysis

Roger
Photos at: http://www.clarkvision.com
 
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ray
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      02-08-2007
On Wed, 07 Feb 2007 14:46:45 +0000, Paul D. Sullivan wrote:

> I read an article on Cnet about how 8 or 10 megapixel cameras are
> not as good as they could be because their megapixel capability
> does not match sensor sizes well. If you buy a camera with 8 or
> 10 megapixels and they have some really small sensor, the extra
> megapixels will not be realized in terms of quality.
>
> Got me thinking - what are some of the best matches of megapixel
> capability to sensor size?
>
> How does the Canon a640 mentioned in the article hold up?
>
> How does the Canon S3 IS hold up?
>
> Olympus Evolt series with those 4/3rds sized sensors?
>
> Do Fuji, Kodak, Nikon and others have a good ratio on average, or
> are certain models better than others?
>
> I'd like to think that consumers aren't getting screwed when they
> want to get to an 8 or 10 megapixel camera, and wanted to ask
> some of ya'all here about it so I could learn what up.
>
> Any helpful answers would be appreciated.
>
> Thanks


FWIW - I remember two or three years ago reading that the latest crop of 8
mp cameras (pretty much state of the art then) were suffering from
crosstalk and not giving the results that had been anticipated.

 
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Paul D. Sullivan
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      02-08-2007
Great reply. Thank you very much.

How does the Canon A640 hold up, if you don't mind? Does it give
a good combination for a 10 megapixel camera?

> Paul D. Sullivan wrote:
>> I read an article on Cnet about how 8 or 10 megapixel cameras
>> are not as good as they could be because their megapixel
>> capability does not match sensor sizes well. If you buy a
>> camera with 8 or 10 megapixels and they have some really
>> small sensor, the extra megapixels will not be realized in
>> terms of quality. Got me thinking - what are some of the best
>> matches of
>> megapixel capability to sensor size?

>
> While one can't prove there is an optimum, because the
> trade space of size of a pixel versus performance just keeps
> getting better with larger pixels, I personally think the
> about 6 to 8 micron pixel pitch is the ideal size. That pitch
> allows many pixels to be crammed into an small sensor
> (e.g. about 8 megapixels in APS-C), while still collecting
> enough photons for great performance, including high ISO
> performance. Collecting about 50,000 photons per pixel
> produces beautiful images, and the 6 to 6 micron pixel pitches
> do that. This is the performance point of many DSLRs.
>
> Quantitative data on sensor performance can be found at:
> http://www.clarkvision.com/imagedeta...rmance.summary
>>
>> How does the Canon a640 mentioned in the article hold up?
>>
>> How does the Canon S3 IS hold up?

>
> S3: 2-micron pixel pith: performance near the bottom of the
> range on the plots on the above page.
>>
>> Olympus Evolt series with those 4/3rds sized sensors?

>
> E300: 5.3 micron pitch should plot in the mid range of
> performance: below most DSLRs and above most P&S.
>>
>> Do Fuji, Kodak, Nikon and others have a good ratio on
>> average, or are certain models better than others?

>
> Look at each model. The newer P&S cameras seem to cram in
> megapixels, and performance per pixel suffers. Most notably,
> the high iso performance (Figures 6 and 7 on the above web
> page).
>>
>> I'd like to think that consumers aren't getting screwed when
>> they want to get to an 8 or 10 megapixel camera, and wanted
>> to ask some of ya'all here about it so I could learn what up.
>>
>> Any helpful answers would be appreciated.
>>
>> Thanks

>
> Manufacturers are trying to hide the noise and low performance
> issues by average pixel in their noise reduction software. So
> what any one camera produces out of camera can be confusing
> and the manufacturers are trying to get you to think they have
> a better solution. But CCD and CMOS sensors have noise
> dominated by photon counting statistics over most of their
> range. That is a fundamental limit, so collecting more
> photons with larger pixels is the only major performance
> metric.
>
> Other related info at:
> http://www.clarkvision.com/imagedeta...ensor_analysis
>
> Roger
> Photos at: http://www.clarkvision.com



 
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Paul D. Sullivan
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      02-08-2007
Yeah, that's kind of what that article was saying.

For me, I would want 8mp so I can get 300 dpi of resolvable
detail on 8x10 prints. I almost never go over 8x10, so figure
8mp is the sweet spot.

But I'd hate to think that extra 3 megapixels overy my 5
megapixel C5050 was simply "hot air" and not worth the
investment.

> FWIW - I remember two or three years ago reading that the
> latest crop of 8 mp cameras (pretty much state of the art
> then) were suffering from crosstalk and not giving the results
> that had been anticipated.



 
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Paul D. Sullivan
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      02-08-2007
That's a ton of data that I can't begin to understand. I wonder
if you would be so kind as to help summarize it in simpler terms?

For example, you indicate that the 4/3rds in the Oly Evolt is mid
range. That makes sense and I can understand that.

But I guess I'd further ask, what megapixel size is that sensor
able to resolve properly? Is 8 mp a good fit for that 4/3rds
sensor? Would it max out at 8 mp or would it also work well for
10 mp or 12 mp too?

Thanks much.

> While one can't prove there is an optimum, because the
> trade space of size of a pixel versus performance just keeps
> getting better with larger pixels, I personally think the
> about 6 to 8 micron pixel pitch is the ideal size. That pitch
> allows many pixels to be crammed into an small sensor
> (e.g. about 8 megapixels in APS-C), while still collecting
> enough photons for great performance, including high ISO
> performance. Collecting about 50,000 photons per pixel
> produces beautiful images, and the 6 to 6 micron pixel pitches
> do that. This is the performance point of many DSLRs.



 
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ASAAR
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      02-08-2007
On Thu, 08 Feb 2007 06:36:46 GMT, Paul D. Sullivan wrote:

> For me, I would want 8mp so I can get 300 dpi of resolvable
> detail on 8x10 prints. I almost never go over 8x10, so figure
> 8mp is the sweet spot.
>
> But I'd hate to think that extra 3 megapixels overy my 5
> megapixel C5050 was simply "hot air" and not worth the
> investment.


It's not hot air, but it may provide less than you expect. From
looking at some of dpreview's resolution tests for various cameras,
I'd say that based on the resolution of the 7mp sensor in Canon's
A620, the 10mp sensor in the A640 greater resolution, but only the
increase that you'd expect to see going from 7mp to 8mp. It may be
a different story for other cameras with other sensors.

It's very easy to see exactly what you'll get by going from the
C5050 to a specific camera with an 8mp sensor. Dpreview has a full
review for the C5050. Look at the resolution chart sections and the
studio scene comparisons. Some of the items will probably have
changed in the studio scenes over the years, but there should be
several that are still being used. Don't look at what appears on
the web page, but download the full sized studio scene images (not
all of them, just choose a couple of the better, low ISO versions).
These should each be several MB in size. Differences in resolvable
detail should be obvious using whatever program you normally use to
view photos on your computer. The last review web page shows a
sample image gallery containing pictures taken with the camera being
reviewed. These will be of different types of pictures more
representative of the shots real people take - no artificial test
images. So you can download a few of these for more comparisons.
These should show you exactly what you can expect from any of the
reviewed cameras. The best place to quickly find them is here:

http://www.dpreview.com/reviews/default.asp?view=alpha

 
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Paul D. Sullivan
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      02-08-2007
Thank you again. So the 10mp and sensor configuration in the
A640 really is not able to fully resolve those 10mp in a useful
or proper way? You are not truly getting the full possible
benefit from those 10 megapixels because the sensor is too small
inside the camera?

> It's not hot air, but it may provide less than you expect.
> From looking at some of dpreview's resolution tests for
> various cameras, I'd say that based on the resolution of the
> 7mp sensor in Canon's A620, the 10mp sensor in the A640
> greater resolution, but only the increase that you'd expect to
> see going from 7mp to 8mp. It may be a different story for
> other cameras with other sensors.



 
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ASAAR
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      02-08-2007
On Thu, 08 Feb 2007 08:01:35 GMT, Paul D. Sullivan wrote:

> Thank you again. So the 10mp and sensor configuration in the
> A640 really is not able to fully resolve those 10mp in a useful
> or proper way? You are not truly getting the full possible
> benefit from those 10 megapixels because the sensor is too small
> inside the camera?


Not at all. I don't really understand how the 10mp sensor would
be considered to be not useful or not be able to resolve detail
properly. Some may say that it shows that Canon should have used a
larger sensor if they wanted to take the A6xx series up to 10mp, but
that probably would have been a mistake. It would have almost
certainly resulted in a camera that wasn't an incremental upgrade
from previous versions. The camera and lens probably would have
been larger. Someone owning a previous model such as the A610 or
A620 that had also purchased the wide or tele lens adapters may have
found themselves unable to use them with the A640. The A640's 10mp
sensor won't have the resolution of a good 10mp DSLR, but the
resolution it does provide is probably about as good as the
resolution you'd get from other 10mp P&S cameras using the same size
sensor. All I meant was to say that higher resolution alone is not
a good reason to upgrade, if you'll only be upgrading from a 7 or
8mp sensor, since the benefit is not as great as the numbers
indicate. The difference between the A640's 10mp sensor and any P&S
camera's 5mp sensor should be considerable, and the newer cameras
should also be faster, much easier on batteries, and have better
high ISO performance. The reviews indicate that even though more
pixels are squeezed into the same size sensor that is used by the
7mp sensor in the A620 (which I own), Canon has managed to do so
without degrading the image with more noise. My preference would
have been to keep the A640 at 7mp and try to reduce the noise (ie,
increase the usable ISO a notch or two). But other people might
prefer the higher resolution. An alternative would be to check out
the A630, the A640's smaller, less expensive 8mp sibling.

 
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