Need help in calculating digital camera's MP

On Fri, 02 Jan 2009 06:13:01 -0800, aniramca wrote:

For a 46 in high definition TV (1920x1080 Panel resolution) - 1080p Full
HD definition, the screen size of the TV is 40 in. x 23 in. ( 102 cm x
58 cm). How many MP digital camera that I need to have JPG photos, so
that I can watch clear, sharp, crisp JPG photos on the TV? I must admit
that I don't have much knowledge about the pixels in digital
cameras,etc. and how that translates into the high definition TV.
Therefore, I do need practical, layman terms answers for info or links
to specific discussion to any websites. What about for the 52 in. TV, 56
in. TV, etc?. Is there a chart available somewhere?. I recall a table
showing how MP is connected to photo print sizes (at the photo printing
stores). But this screen size is much larger than those listed - perhaps
more for poster sizes. Someone may ask on how close you are watching the
TV screen... and I am thinking about relatively close range, say 5 ft
distance. Thanks for the info!

Basically, 1920x1080 is about 2mp - anything beyond that is overkill -
you can't display more than the resolution of the output device.

ray wrote:
[]
Basically, 1920x1080 is about 2mp - anything beyond that is overkill -
you can't display more than the resolution of the output device.

... although a "normal" 4:3 aspect ratio camera needs to be 1920 x 1440
pixels to at least match the display resolution horizontally (i.e. 2.76
Mpix), and it would be helpful to have some crop margin for those times
when your framing isn't perfect , so say 5-6Mpix.

Leaving the question, are any current cameras less than 5-6Mpix?

David

On Fri, 02 Jan 2009 16:41:10 +0000, David J Taylor wrote:

ray wrote:
[]
Basically, 1920x1080 is about 2mp - anything beyond that is overkill -
you can't display more than the resolution of the output device.

.. although a "normal" 4:3 aspect ratio camera needs to be 1920 x 1440
pixels to at least match the display resolution horizontally (i.e. 2.76
Mpix), and it would be helpful to have some crop margin for those times
when your framing isn't perfect , so say 5-6Mpix.

Leaving the question, are any current cameras less than 5-6Mpix?

David

According to my calculations, at 4:3, the image would only need to be
1440x1080 - any larger and you'd drop of the top and bottom. So I guess
he only needs about 1.5mp.

ray wrote:

On Fri, 02 Jan 2009 16:41:10 +0000, David J Taylor wrote:

ray wrote:
[]
Basically, 1920x1080 is about 2mp - anything beyond that is overkill -
you can't display more than the resolution of the output device.

.. although a "normal" 4:3 aspect ratio camera needs to be 1920 x 1440
pixels to at least match the display resolution horizontally (i.e. 2.76
Mpix), and it would be helpful to have some crop margin for those times
when your framing isn't perfect , so say 5-6Mpix.

Leaving the question, are any current cameras less than 5-6Mpix?

David

According to my calculations, at 4:3, the image would only need to be
1440x1080 - any larger and you'd drop of the top and bottom. So I guess
he only needs about 1.5mp.

I make family DVDs for 16:9 widescreen TV. One major source of content
is JPEG output from my Canon Ixus 60. I use its full (modest!)
resolution of 2816 x 2112 (AR=4.3), which allows me adequate scope for
pans/zooms. If I move up to HD DVDs (the TV is HD-ready) then I'll
probably upgrade my camera.

Anyway, in general I'd choose the highest possible resolution every
time, as I like to edit my hasty compositions on the PC. And that's
where sometimes I can create heavily-zoomed crops that I'd either
missed or had no time to capture in the field. Of course, I'm coming
at this just as a point-and-shoot guy, not a pro or serious amateur.

--
Terry, East Grinstead, UK

ray wrote:
On Fri, 02 Jan 2009 16:41:10 +0000, David J Taylor wrote:

ray wrote:
[]
Basically, 1920x1080 is about 2mp - anything beyond that is
overkill - you can't display more than the resolution of the output
device.

.. although a "normal" 4:3 aspect ratio camera needs to be 1920 x
1440 pixels to at least match the display resolution horizontally
(i.e. 2.76 Mpix), and it would be helpful to have some crop margin
for those times when your framing isn't perfect , so say 5-6Mpix.

Leaving the question, are any current cameras less than 5-6Mpix?

David

According to my calculations, at 4:3, the image would only need to be
1440x1080 - any larger and you'd drop of the top and bottom. So I
guess he only needs about 1.5mp.

You want the full resolution in each dimension, which, for a 4:3 sensor,
means a 1920 x 1440 pixel image, cropped vertically to 1920 x 1080. As
Terry say, though, in general a little more resolution is handy.

David

Terry Pinnell wrote:
[]
Anyway, in general I'd choose the highest possible resolution every
time, as I like to edit my hasty compositions on the PC. And that's
where sometimes I can create heavily-zoomed crops that I'd either
missed or had no time to capture in the field. Of course, I'm coming
at this just as a point-and-shoot guy, not a pro or serious amateur.

There's another reason for using more pixels. In the display, each of the
pixels is an RGB triple, i.e. a full colour pixel, whereas in the camera
each pixel is either red, green or blue. So to match the display
resolution, you may need more pixels in the (Bayer) camera than are on the
display. I don't know if any tests have been done to check what the
actual ratio is, but I recall that the Foveon sensor is reckoned by some
to be equivalent to something like twice the number of pixels.

I therefore revise my estimate to, for a 4:3 aspect ratio camera 2 * 1920
* 1440, i.e. about 5-6Mpix, resampled and cropped to a 16:9 1920 x 1080
ready-to-display image.

Cheers,
David

On Fri, 02 Jan 2009 18:51:25 GMT, "David J Taylor"
wrote in
:

Terry Pinnell wrote:
[]
Anyway, in general I'd choose the highest possible resolution every
time, as I like to edit my hasty compositions on the PC. And that's
where sometimes I can create heavily-zoomed crops that I'd either
missed or had no time to capture in the field. Of course, I'm coming
at this just as a point-and-shoot guy, not a pro or serious amateur.

There's another reason for using more pixels. In the display, each of the
pixels is an RGB triple, i.e. a full colour pixel, whereas in the camera
each pixel is either red, green or blue. So to match the display
resolution, you may need more pixels in the (Bayer) camera than are on the
display.

Most current TV electronics aren't capable of that kind of pixel level
resolution -- put the HD input on pause and look closely -- and your
eyes couldn't see it in a moving image even if.

I don't know if any tests have been done to check what the
actual ratio is, but I recall that the Foveon sensor is reckoned by some
to be equivalent to something like twice the number of pixels.

That's not directly comparable.

I therefore revise my estimate to, for a 4:3 aspect ratio camera 2 * 1920
* 1440, i.e. about 5-6Mpix, resampled and cropped to a 16:9 1920 x 1080
ready-to-display image.

Cropping a movie is usually impractical.
2-3 MP is really enough.

--
Very best wishes for the holiday season and for the coming new year,
John

John Navas wrote:
[]
Most current TV electronics aren't capable of that kind of pixel level
resolution -- put the HD input on pause and look closely -- and your
eyes couldn't see it in a moving image even if.

I don't know if any tests have been done to check what the
actual ratio is, but I recall that the Foveon sensor is reckoned by
some to be equivalent to something like twice the number of pixels.

That's not directly comparable.

I therefore revise my estimate to, for a 4:3 aspect ratio camera 2 *
1920 * 1440, i.e. about 5-6Mpix, resampled and cropped to a 16:9
1920 x 1080 ready-to-display image.

Cropping a movie is usually impractical.
2-3 MP is really enough.

The LCD TVs I've seen are quite capable of pixel-level resolution, John.
Recall that the OP wants stills, not movies.

David

On Fri, 02 Jan 2009 20:04:19 GMT, "David J Taylor"
wrote in
:

John Navas wrote:
[]
Most current TV electronics aren't capable of that kind of pixel level
resolution -- put the HD input on pause and look closely -- and your
eyes couldn't see it in a moving image even if.

I don't know if any tests have been done to check what the
actual ratio is, but I recall that the Foveon sensor is reckoned by
some to be equivalent to something like twice the number of pixels.

That's not directly comparable.

I therefore revise my estimate to, for a 4:3 aspect ratio camera 2 *
1920 * 1440, i.e. about 5-6Mpix, resampled and cropped to a 16:9
1920 x 1080 ready-to-display image.

Cropping a movie is usually impractical.
2-3 MP is really enough.

The LCD TVs I've seen are quite capable of pixel-level resolution, John.

Brand and model please.

--
Very best wishes for the holiday season and for the coming new year,
John

In article , David J
Taylor
wrote:

There's another reason for using more pixels. In the display, each of the
pixels is an RGB triple, i.e. a full colour pixel, whereas in the camera
each pixel is either red, green or blue. So to match the display
resolution, you may need more pixels in the (Bayer) camera than are on the
display. I don't know if any tests have been done to check what the
actual ratio is, but I recall that the Foveon sensor is reckoned by some
to be equivalent to something like twice the number of pixels.

the foveon fans come up with their own math to justify the sensor's
existence. it's often hilarious. i've seen everything from 1.4x to
over 3x, with some even claiming infinite resolution, depending on how
creative the (misinformed) zealot is. the main difference is not the
co-located layers, but rather the false detail from the lack of an
anti-alias filter and heavy sharpening in the raw processing.