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high optical vs. large megapixel ?



 
 
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  #1  
Old July 26th 04, 05:34 PM
chesham
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Default high optical vs. large megapixel ?

Hello, I can see where you are coming from ... but I haven't a clue on this
one!

I tend to say that high pixel is better in low light conditions ... and the
zoom is of better use in the better lighting!

Just be sure that you AVOID digital zoom ... OK!


Jon


"Andy" wrote in message
...
Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix

2800Zoom
(2.0MP, 6X Optical), i got reasonable pictures, and looking at the picture
on the PC monitor (and no zooming in/out of picture) the plane looks to be
about 7cm on screen. Now, what i am trying to find out is, forgetting
picture QUALITY, would i have got similar results with a camera with only

a
3X optical zoom, but having 4 or 5MP ? (i.e. without any zooming of the
picture on screen, would the plane still look to be 7cm ?.

Hope someone knows what i'm going on about !

Cheers
Andy




  #2  
Old July 26th 04, 09:35 PM
Andy100
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Default high optical vs. large megapixel ?

Yeah, thanks for the info. I do tend to stay well clear of digital zoom,
because I, probably like many others fell into the trap of using it only to
find out it's horrible !!

Cheers
Andy


"chesham" wrote in message
...
Hello, I can see where you are coming from ... but I haven't a clue on

this
one!

I tend to say that high pixel is better in low light conditions ... and

the
zoom is of better use in the better lighting!

Just be sure that you AVOID digital zoom ... OK!


Jon


"Andy" wrote in message
...
Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix

2800Zoom
(2.0MP, 6X Optical), i got reasonable pictures, and looking at the

picture
on the PC monitor (and no zooming in/out of picture) the plane looks to

be
about 7cm on screen. Now, what i am trying to find out is, forgetting
picture QUALITY, would i have got similar results with a camera with

only
a
3X optical zoom, but having 4 or 5MP ? (i.e. without any zooming of the
picture on screen, would the plane still look to be 7cm ?.

Hope someone knows what i'm going on about !

Cheers
Andy






  #3  
Old July 26th 04, 09:38 PM
Matt Ion
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Posts: n/a
Default high optical vs. large megapixel ?

"Andy" wrote in message
...
Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).


Absolutely not.

For starters, magnifaction ratings can mean two different things, and in
either case, it's a relative reading. In the case of zoom lenses, or lenses
with adjustable magnification, which is what we're dealing with here, it's
simply a comparison between the highest and lowest magnification factor. A
higher rating (6X) means you have a wider range between the lens's
wide-angle and close-up settings.

The other measurement is used for fixed-magnification devices like
binoculars, telescopes, microscopes, etc. and refers to excatly how much an
object is magnified, which is probably what you're thinking of, but that
doesn't apply to cameras of any sort, because the final output can affect
the size of an object in the picture as well.

Second, megapixels is only half the story when it comes to sensors; the
actual size of the sensor affects things as well.

A certain lens's magnification depends first of all on the size of the
target area. I'm a little rusty on the math, so if I'm off, someone correct
me (nicely), but as I recall... magnification can be calculated by focal
length divided by the diagonal of the target frame. A 35mm film frame has a
diagonal of around 55mm, so a standard 50mm lens gives you very close to 1X
(or 1:1) magnification. A 100mm lens would be 2X, 200mm would be 4X, and so
on.

When you get into digital sensors, they're typically smaller than 35mm film,
so the magnification for a specific lens length increases. Say your sensor
is 33mm diagonally; a 100mm lens would then be about 3X magnification and
show a smaller area than the same lens on a 35mm camera.

For a given size of sensor, magnification will always be the same for a
given lens regardless of megapixels, but the actual size of the image in
pixels will vary. As a direct comparison, my Kodak 3.2MP camera output
images of 2080x1544; my Canon 6.3MP camera outputs at 3072x2048. For the
sake of argument, say the sensor is the same size, and the lens the same
length, on both cameras: both will then take the exact same image, area-wise
(same magnification).

The Kodak camera, however, breaks it into fewer pieces, so each piece is
going to be larger than with the Canon. If you resized the Kodak image to
match the pixel size of the Canon, you'd find the picture a fair bit noiser,
with rougher edges to objects, because those 3.2 million bits of picture
must be expanded by an uneven factor.

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix

2800Zoom
(2.0MP, 6X Optical), i got reasonable pictures, and looking at the picture
on the PC monitor (and no zooming in/out of picture) the plane looks to be
about 7cm on screen. Now, what i am trying to find out is, forgetting
picture QUALITY, would i have got similar results with a camera with only

a
3X optical zoom, but having 4 or 5MP ? (i.e. without any zooming of the
picture on screen, would the plane still look to be 7cm ?.


Again, in this usage, zoom factor refers only to the range of the lens from
shortest to longest focal length. Using the numbers above, a lens that
zooms from 50mm to 200mm would be a "4X optical zoom", regardless of the
actual magnification numbers: magnification will be four times greater at
the tightest angle than at the widest angle.

Higher megapixels will let you get away with a shorter lens for the same
quality pictures, but exactly how it affects your example above depends on
the actual magnification involved, which will depend on the relative sizes
of the two cameras' sensors, and the precise zoom setting you're using.


  #4  
Old July 26th 04, 10:44 PM
Ol' Bab
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Default high optical vs. large megapixel ?

Andy wrote:

Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).

By 6x zoom, I'm betting you mean "a lens with twice the
maximum focal length"

No, the number you'd get is 1.25 Mp -ie, one quarter. The
resolution IS doubled but the pixel count is SQUARED.

This assumes your targets of choice are songbirds at a feeder
across the parking lot, and you can't get closer, so whatever
camera you use, the results must be cropped.

So if you just can't move closer, a LONG telephoto (say 4x
longer) will save a thunder of money: make your 5 Mp act like
an 80 Mp !! Of course now you need a tripod, and the flash is
hopeless.

Trade-offs, trade-offs.

Ol' Bab
  #5  
Old July 26th 04, 11:29 PM
Roland Karlsson
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Posts: n/a
Default high optical vs. large megapixel ?

"Andy" wrote in :

Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).


That depends on what you are planning to photo.

If it is something that fills the frame and where
you want to be able to make larger prints - no.

If it is song birds that fills just a small bit
of the actual frame, you can actually get away with
1.5 Mpixels at 6x zoom.

But - in the latter case - 20x zoom would be better.


/Roland
  #6  
Old July 26th 04, 11:49 PM
Joseph Meehan
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Posts: n/a
Default high optical vs. large megapixel ?

Andy wrote:
Pardon my ignorance, but am i right in thinking that a camera with a
3 X Optical Zoom having 5MPixels, is about the same as a camera
having a 6 X Optical Zoom with 2.5MPixels (i know you don't often get
2.5MP, but just theoretically).

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix
2800Zoom (2.0MP, 6X Optical), i got reasonable pictures, and looking
at the picture on the PC monitor (and no zooming in/out of picture)
the plane looks to be about 7cm on screen. Now, what i am trying to
find out is, forgetting picture QUALITY, would i have got similar
results with a camera with only a 3X optical zoom, but having 4 or
5MP ? (i.e. without any zooming of the picture on screen, would the
plane still look to be 7cm ?.

Hope someone knows what i'm going on about !

Cheers
Andy


As, Ol' Bab pointed out, no. In addition with the 5MP camera you also
have the option of using it at 3X or less and getting the full 5MP and the
option of cropping it at your leisure if you like or using the full 5MP


--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math



  #7  
Old July 27th 04, 01:47 AM
Si
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Posts: n/a
Default high optical vs. large megapixel ?

your ignorance has been pardonned

take everything above with a pinch of salt

Si

"Andy" wrote in message
...
Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix

2800Zoom
(2.0MP, 6X Optical), i got reasonable pictures, and looking at the picture
on the PC monitor (and no zooming in/out of picture) the plane looks to be
about 7cm on screen. Now, what i am trying to find out is, forgetting
picture QUALITY, would i have got similar results with a camera with only

a
3X optical zoom, but having 4 or 5MP ? (i.e. without any zooming of the
picture on screen, would the plane still look to be 7cm ?.

Hope someone knows what i'm going on about !

Cheers
Andy




  #8  
Old July 27th 04, 11:20 AM
Hans-Georg Michna
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Posts: n/a
Default high optical vs. large megapixel ?

On Mon, 26 Jul 2004 17:13:38 +0100, "Andy"
wrote:

Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).


Andy,

Ol' Bab already wrote it, and Joseph reinforced it. Your thought
is correct for max zoom shots including 2 x digital zoom for the
3 x optical zoom camera.

However, the mathematics are wrong. You'd need 10 Megapixels to
arrive at the same 2.5 Megapixel photo.

However, at shorter zoom settings the two cameras would be
different. The one with the more pixels would deliver photos
with more genuine pixels.

Hans-Georg

--
No mail, please.
  #9  
Old July 27th 04, 04:05 PM
Andy100
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Posts: n/a
Default high optical vs. large megapixel ?

Thanks for all the info (wish i'd never asked !!)

Cheers
Andy


"Hans-Georg Michna" wrote in message
...
On Mon, 26 Jul 2004 17:13:38 +0100, "Andy"
wrote:

Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).


Andy,

Ol' Bab already wrote it, and Joseph reinforced it. Your thought
is correct for max zoom shots including 2 x digital zoom for the
3 x optical zoom camera.

However, the mathematics are wrong. You'd need 10 Megapixels to
arrive at the same 2.5 Megapixel photo.

However, at shorter zoom settings the two cameras would be
different. The one with the more pixels would deliver photos
with more genuine pixels.

Hans-Georg

--
No mail, please.



  #10  
Old July 27th 04, 06:37 PM
Don Stauffer
external usenet poster
 
Posts: n/a
Default high optical vs. large megapixel ?

Only if the only reason you have the camera is to shoot objects at
inaccessible distances.

I personally would rather have the 5MP camera. I still shoot most of my
pictures with a 'normal' focal length, and want as many pixels in my
image as possible, regardless of the focal length I am using.

Andy wrote:

Pardon my ignorance, but am i right in thinking that a camera with a 3 X
Optical Zoom having 5MPixels, is about the same as a camera having a 6 X
Optical Zoom with 2.5MPixels (i know you don't often get 2.5MP, but just
theoretically).

This weekend i was at the Sunderland Airshow, i have a Fuji Finepix 2800Zoom
(2.0MP, 6X Optical), i got reasonable pictures, and looking at the picture
on the PC monitor (and no zooming in/out of picture) the plane looks to be
about 7cm on screen. Now, what i am trying to find out is, forgetting
picture QUALITY, would i have got similar results with a camera with only a
3X optical zoom, but having 4 or 5MP ? (i.e. without any zooming of the
picture on screen, would the plane still look to be 7cm ?.

Hope someone knows what i'm going on about !

Cheers
Andy


--
Don Stauffer in Minnesota

webpage-
http://www.usfamily.net/web/stauffer
 




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