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megapixels and sensor size

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Anonymous
August 28, 2005 3:10:04 PM

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

Since it looks like Canon is coming out with a full 35mm frame sensor,
and it's about 6mp, would that be the equivalent to the current sensor
size but with 3mp?

I would think for the same density of megapixels in the larger frame,
the number of MPs would go up proportionately.

Or is this not right?

More about : megapixels sensor size

Anonymous
August 28, 2005 10:49:59 PM

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

On Sun, 28 Aug 2005 11:10:04 -0700, Jon Nadelberg <news@nadelberg.com>
wrote:

>Since it looks like Canon is coming out with a full 35mm frame sensor,
>and it's about 6mp, would that be the equivalent to the current sensor
>size but with 3mp?
>
>I would think for the same density of megapixels in the larger frame,
>the number of MPs would go up proportionately.
>
>Or is this not right?

It's 12 megapixels and here is what you want to know...

http://www.dpreview.com/articles/canoneos5d/

A comparison of pixel density and size to sensor size...
*************************************************************

"I believe that all government is evil,
in that all government must necessarily make war upon liberty...

From "Mencken's Creed"
H.L. Mencken (1880 -1956)
Anonymous
August 28, 2005 10:50:00 PM

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

John A. Stovall wrote:
> On Sun, 28 Aug 2005 11:10:04 -0700, Jon Nadelberg <news@nadelberg.com>
> wrote:
>
>
>>Since it looks like Canon is coming out with a full 35mm frame sensor,
>>and it's about 6mp, would that be the equivalent to the current sensor
>>size but with 3mp?
>>
>>I would think for the same density of megapixels in the larger frame,
>>the number of MPs would go up proportionately.
>>
>>Or is this not right?
>
>
> It's 12 megapixels and here is what you want to know...
>
> http://www.dpreview.com/articles/canoneos5d/
>
> A comparison of pixel density and size to sensor size...

OK, read it. So they did make the pixels large to compensate for the
larger sensor size. I assume that because the canon EOS 1DS has a
larger pixel size than the Nikon D2X, but has a bigger overall MP count,
that the Canon has a somewhat larger sensor than the Nikon.

So, if you increase the pixel count for the 5D, how much resolution do
you lose? It seems to me that while it has a full frame sensor, it is
simply not going to have close to the same sort of resolution that you
could get with smaller sensor 12.8 mp cameras.
Related resources
August 28, 2005 11:26:09 PM

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

"Jon Nadelberg" <news@nadelberg.com> wrote in message
news:BOOdnbeZNLJjYIzeRVn-rw@rcn.net...
> Since it looks like Canon is coming out with a full 35mm frame sensor, and
> it's about 6mp,

The 5D has 12.8MPs

>would that be the equivalent to the current sensor size but with 3mp?

The 5D sensor surface area is 2.535 x the 20D sensor so presumably
12.8/2.535 = 5MPs

> I would think for the same density of megapixels in the larger frame, the
> number of MPs would go up proportionately.
>
> Or is this not right?

Yes (if I understand the question)
Anonymous
August 28, 2005 11:26:10 PM

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

On Sun, 28 Aug 2005 19:26:09 +0100, "dylan" <no@nowhere.com> wrote:

>
>"Jon Nadelberg" <news@nadelberg.com> wrote in message
>news:BOOdnbeZNLJjYIzeRVn-rw@rcn.net...
>> Since it looks like Canon is coming out with a full 35mm frame sensor, and
>> it's about 6mp,
>
>The 5D has 12.8MPs
>
>>would that be the equivalent to the current sensor size but with 3mp?
>
>The 5D sensor surface area is 2.535 x the 20D sensor so presumably
>12.8/2.535 = 5MPs

No, the 5D pixel size is 8.5x8.5 µm while the 20D pixel size is
6.4x6.4 µm.


*************************************************************

"I believe that all government is evil,
in that all government must necessarily make war upon liberty...

From "Mencken's Creed"
H.L. Mencken (1880 -1956)
Anonymous
August 28, 2005 11:26:10 PM

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

dylan wrote:
> "Jon Nadelberg" <news@nadelberg.com> wrote in message
> news:BOOdnbeZNLJjYIzeRVn-rw@rcn.net...
>
>>Since it looks like Canon is coming out with a full 35mm frame sensor, and
>>it's about 6mp,
>
>
> The 5D has 12.8MPs
>

Oh, ok. So, 12.8 MPs.

So the density of pixels is about the same, just a bigger area.

I guess I'm just trying to see where MP counts come in when you have a
different sensor size. Since the 5D has such a larger sensor, then the
12.8 MP would not be equivalent in resolution to a 12.8 MP camera with a
smaller sensor, such as a D2X (not that I'm about to buy that....).

Also, if the pixel size is a bit larger, how does that affect
resolution? I would think a larger pixel size would reduce resolution,
but probably not where it is really noticeable.
Anonymous
August 29, 2005 12:27:46 AM

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

"Jon Nadelberg" <news@nadelberg.com> wrote in message
news:BOOdnbeZNLJjYIzeRVn-rw@rcn.net...
> Since it looks like Canon is coming out with a full 35mm frame sensor, and
> it's about 6mp, would that be the equivalent to the current sensor size
> but with 3mp?
>
> I would think for the same density of megapixels in the larger frame, the
> number of MPs would go up proportionately.
>
> Or is this not right?

See the pixel comparison, here:
http://www.dpreview.com/articles/canoneos5d/

Near the bottom of the page.

BTW, the 5D is 12.8 megapixel, not 6. Six was passed a couple of
generations ago...
--
Skip Middleton
http://www.shadowcatcherimagery.com
August 29, 2005 12:38:08 AM

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

"John A. Stovall" <johnastovall@earthlink.net> wrote in message
news:9s14h1tema2ht7ncilaujb67n5nafqto7k@4ax.com...
> On Sun, 28 Aug 2005 19:26:09 +0100, "dylan" <no@nowhere.com> wrote:
>
>>
>>"Jon Nadelberg" <news@nadelberg.com> wrote in message
>>news:BOOdnbeZNLJjYIzeRVn-rw@rcn.net...
>>> Since it looks like Canon is coming out with a full 35mm frame sensor,
>>> and
>>> it's about 6mp,
>>
>>The 5D has 12.8MPs
>>
>>>would that be the equivalent to the current sensor size but with 3mp?
>>
>>The 5D sensor surface area is 2.535 x the 20D sensor so presumably
>>12.8/2.535 = 5MPs
>
> No, the 5D pixel size is 8.5x8.5 µm while the 20D pixel size is
> 6.4x6.4 µm.

No ?
Is that what he meant, pixel size not sensor size ?, not how I read it but
you maybe right.
Anonymous
August 29, 2005 10:14:25 AM

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

> I would think for the same density of megapixels in the larger frame, the
> number of MPs would go up proportionately.

Maybe each of the pixels are bigger?

Toa
Anonymous
August 29, 2005 12:18:34 PM

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

Jon Nadelberg wrote:
> dylan wrote:
[]
>> The 5D has 12.8MPs
>>
>
> Oh, ok. So, 12.8 MPs.
>
> So the density of pixels is about the same, just a bigger area.
>
> I guess I'm just trying to see where MP counts come in when you have a
> different sensor size. Since the 5D has such a larger sensor, then
> the 12.8 MP would not be equivalent in resolution to a 12.8 MP camera
> with a smaller sensor, such as a D2X (not that I'm about to buy
> that....).
> Also, if the pixel size is a bit larger, how does that affect
> resolution? I would think a larger pixel size would reduce
> resolution, but probably not where it is really noticeable.

In the final image, viewed at a constant size, the number of pixels
affects the apparent quality of the image as perceived by the viewer. So
the same scene taken with a 6MP sensor would not look as sharp as with a
12MP sensor, but you may need to hold the print quite close to see this
(depending on the print size).

As the 5D has larger pixels, when using the same lens each pixel will have
a larger angular subtense and so cover a greater area of the scene. Each
pixel subtense is a lower spatial frequency, and therefore be working in a
region of the MTF curve for the lens nearer to the left side, perhaps
where the MTF is higher. Therefore, the 5D's pixels should be less
reliant on lenses with an extended MTF, so the lens should be less of a
limiting factor in terms of image resolution.

Of course, the trade-off for the lower resolution is the wider angular
field of view of the image with a given lens. There is another effect as
well independant of lens. Rays of light near the edge of the sensor
arrive at a greater angle of incidence than those at the centre. In a
full-frame sensor the angle of arrival is greater than in a smaller sensor
(for the same lens), and this makes it more difficult for the sensor to
respond correctly. It remains to be seen how well Canon have dealt with
this problem.

David
August 29, 2005 12:50:17 PM

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

>
> Oh, ok. So, 12.8 MPs.
>
> So the density of pixels is about the same, just a bigger area.
>
> I guess I'm just trying to see where MP counts come in when you have a
> different sensor size. Since the 5D has such a larger sensor, then the
> 12.8 MP would not be equivalent in resolution to a 12.8 MP camera with a
> smaller sensor, such as a D2X (not that I'm about to buy that....).

The D2X will have higher resolution (its covers a smaller area of the image)
BUT theoretically will have a worse noise figure due to smaller pixels.
read the bottom of this page http://www.dpreview.com/articles/canoneos5d/

> Also, if the pixel size is a bit larger, how does that affect resolution?

It's obviously lower but noise is better.

I would think a larger pixel size would reduce resolution,
> but probably not where it is really noticeable.

Resolution is noticable, all other things equal, until you reach the limit
of the eye.

Cheers
August 29, 2005 12:52:48 PM

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

> OK, read it. So they did make the pixels large to compensate for the
> larger sensor size. I assume that because the canon EOS 1DS has a larger
> pixel size than the Nikon D2X, but has a bigger overall MP count, that the
> Canon has a somewhat larger sensor than the Nikon.
>
> So, if you increase the pixel count for the 5D, how much resolution do you
> lose?

None you improve resolution

> It seems to me that while it has a full frame sensor, it is simply not
> going to have close to the same sort of resolution that you could get with
> smaller sensor 12.8 mp cameras.

Correct, but you will find that resolution isn't everything, noise can be
more important.
Anonymous
August 29, 2005 3:45:34 PM

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

Jon Nadelberg <news@nadelberg.com> writes:
> Also, if the pixel size is a bit larger, how does that affect
> resolution? I would think a larger pixel size would reduce
> resolution, but probably not where it is really noticeable.

It will give you less resolution at the surface of the sensor, yes.
But it is very few of us that view our photographs by examining
the photon wells at the surface of the sensor.

The normal way to view a photograph is to make a print on
(20 x 30 cm say) paper, and then look at this print.

If your favoured way of looking at photpgraphs is viewing prints,
(rather than sensors), you'll discover that the pixel has no size,
and the most important characteristic to determine maximum resolution
is the /pixel count/.

(The size of physical sensor cells still matters, because they
decide such factors as noise, dynamic range, etc. - but for all
those factors, bigger is generally better.)

This particular aspect of digital photography seems to confuse
some people, so I've but up a webpage where I try to answer
the most frequently asked questions about pixels, please see:
http://folk.uio.no/gisle/photo/pixels.html

--
- gisle hannemyr [ gisle{at}hannemyr.no - http://folk.uio.no/gisle/ ]
------------------------------------------------------------------------
Kodak DCS460, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------
Anonymous
August 29, 2005 8:35:45 PM

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

Gisle Hannemyr wrote:
> Jon Nadelberg <news@nadelberg.com> writes:
>
>>Also, if the pixel size is a bit larger, how does that affect
>>resolution? I would think a larger pixel size would reduce
>>resolution, but probably not where it is really noticeable.
>
>
> It will give you less resolution at the surface of the sensor, yes.
> But it is very few of us that view our photographs by examining
> the photon wells at the surface of the sensor.

That's how my photos look best.

But thanks I think I have it.
Anonymous
August 30, 2005 6:26:22 AM

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

"Jon Nadelberg" <news@nadelberg.com> wrote

> Oh, ok. So, 12.8 MPs.
>
> So the density of pixels is about the same, just a bigger area.

No, the 5D pixels are about 20% bigger based on my calculations.

> I guess I'm just trying to see where MP counts come in when you have a
> different sensor size. Since the 5D has such a larger sensor, then the
> 12.8 MP would not be equivalent in resolution to a 12.8 MP camera with a
> smaller sensor, such as a D2X (not that I'm about to buy that....).

Larger pixels = more sensitivity to light and less noise.

> Also, if the pixel size is a bit larger, how does that affect
> resolution? I would think a larger pixel size would reduce resolution,
> but probably not where it is really noticeable.

Larger pixels reduces resolution because you can fit less pixels on the
sensor, but larger pixels perform better and result in higher image quality.

--
Mark

Photos, Ideas & Opinions
http://www.marklauter.com
!