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MegaPixels VS Compression

 
 
Lowryter
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      08-03-2004
OK OK, I just got this Nikon 5700, and I have been experimenting, but haven't
made any prints.

Now this a 5 Megapixel Camera. that controls the Megapixel by: Full, UXGA,
SXGA, XGA, VGA, this equates to print size.

but then the compression is goes from Raw, HI, Fine, Normal, & Basic....

can someone give me a simple understanding of the trade off

the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what happens
when you increase one over another?

yes, it might be a dumb question......

 
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David J Taylor
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Posts: n/a
 
      08-03-2004
Lowryter wrote:
> OK OK, I just got this Nikon 5700, and I have been experimenting,
> but haven't made any prints.
>
> Now this a 5 Megapixel Camera. that controls the Megapixel by: Full,
> UXGA, SXGA, XGA, VGA, this equates to print size.
>
> but then the compression is goes from Raw, HI, Fine, Normal, &
> Basic....
>
> can someone give me a simple understanding of the trade off
>
> the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what
> happens when you increase one over another?
>
> yes, it might be a dumb question......


There are plenty of places you can read about this. My own experience
shows that if you need to compromise on file size (perhaps the only reason
for not taking all pictures at Full resolution, Fine quality), is that you
should keep the Full resolution (2560 x 1920 pixels), but step down from
Fine to Normal or even Basic in the compression settings. Take the same
picture on three different quality settings and see if you can tell the
difference.

Cheers,
David


 
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Joe Bloggs
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Posts: n/a
 
      08-03-2004
http://www.velocityreviews.com/forums/(E-Mail Removed)ojunk (Lowryter) wrote in message news:<(E-Mail Removed)>...
> OK OK, I just got this Nikon 5700, and I have been experimenting, but haven't
> made any prints.
>
> Now this a 5 Megapixel Camera. that controls the Megapixel by: Full, UXGA,
> SXGA, XGA, VGA, this equates to print size.
>
> but then the compression is goes from Raw, HI, Fine, Normal, & Basic....
>
> can someone give me a simple understanding of the trade off
>
> the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what happens
> when you increase one over another?
>
> yes, it might be a dumb question......


Why buy a 5 megapixel camera and use only 2 megapixels when taking
pictures? And then on top of that using 'Normal' compression instead
of 'Raw' or 'Hi'? It's similar to buying a top of the range V12
Mercedes-Benz, then taking half the cylinders out of the engine, and
replacing the seats with those out of a Ford!

Sorry, this really isn't intended as a rant, but I'd suggest using the
highest resolution setting (Full), and either Raw (meaning no
compression) or Hi compression (which strangely enough means very
little compression - compression reduces the quality of the image).
This will result in much larger file sizes for the images, but with
the ridiculously low price of memory cards these days that shouldn't
be too much of an issue if you get a larger capacity card (say, 256MB
or 512MB).

At the end of the day taking pictures is a one-off thing, and you'd be
kicking yourself if you took a fantastic shot and then found you
couldn't print it any larger than 6x4 due to poor quality.
 
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Chicha
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      08-03-2004
(E-Mail Removed)ojunk (Lowryter) wrote in message news:<(E-Mail Removed)>...
> OK OK, I just got this Nikon 5700, and I have been experimenting, but haven't
> made any prints.
>
> Now this a 5 Megapixel Camera. that controls the Megapixel by: Full, UXGA,
> SXGA, XGA, VGA, this equates to print size.
>
> but then the compression is goes from Raw, HI, Fine, Normal, & Basic....
>
> can someone give me a simple understanding of the trade off
>
> the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what happens
> when you increase one over another?
>
> yes, it might be a dumb question......


Not dumb at all.

Since every producer uses their own names for resolution it makes sense
use actual numbers instead of this funny names, like Full (Nikon) or
Large (Canon).Pity they don't use actual JPEG compression ratio (see EXIF)

If your screen set to 1024X768 and you pic taken with equal settings
(SXGA?) it will fill your screen perfectly - no (+-)zoom from viewer program
is required.I think it would be enough to print postcard size picture.
You would not see difference between fine and normal compression
on your screen, may be Basic will show up somehow.

BUT - some pictures I dearly love were originally a part of bigger
picture. If you are thinking about cropping, processing, prining in large
- use upscale settings for both resolution and compression.

Anyway, all this different sizes/compressions are for storing only.
Camera shoots Raw format and JPEG is processed with inbuilt processor
and that process you can perform with editing program on your PC.

So even if you want just slideshow - who nows which screen you to be using
tomorrow?

I would say - buy bigger card and use upscale if you haven't
special requirement that allows you to go downscale.

HTH.

Nick(Chicha)
 
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John Appleby
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      08-03-2004
> Why buy a 5 megapixel camera and use only 2 megapixels when taking
> pictures? And then on top of that using 'Normal' compression instead
> of 'Raw' or 'Hi'? It's similar to buying a top of the range V12
> Mercedes-Benz, then taking half the cylinders out of the engine, and
> replacing the seats with those out of a Ford!


Why? What if you're creating web based content? What if you need to shoot
more pictures than you have memory space to do so? There are lots of reasons
why at times it makes sense to shoot with less than the total available
amount of resolution.

I don't like your analogy. It's nothing like that at all. It's more like VVC
in a Honda - conserving fuel at low revs by adjusting the valve timing.

> At the end of the day taking pictures is a one-off thing, and you'd be
> kicking yourself if you took a fantastic shot and then found you
> couldn't print it any larger than 6x4 due to poor quality.


You're making too many assumptions about what this person is trying to
achieve. If you shoot hi-res pictures only to decrease their size
immediately in every case, you're only wasting time by making the pictures
big.

Regards,

John


 
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John Appleby
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Posts: n/a
 
      08-03-2004
"Lowryter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> OK OK, I just got this Nikon 5700, and I have been experimenting, but

haven't
> made any prints.
>
> Now this a 5 Megapixel Camera. that controls the Megapixel by: Full,

UXGA,
> SXGA, XGA, VGA, this equates to print size.
>
> but then the compression is goes from Raw, HI, Fine, Normal, & Basic....
>
> can someone give me a simple understanding of the trade off
>
> the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what

happens
> when you increase one over another?
>
> yes, it might be a dumb question......


The resolution and quality work hand in hand and relate to what your usage
of the images is going to be. The resolution is simple, just the size of the
output file. The bigger it is, the bigger the image can be enlarged.

The compression is all about the type of output file. RAW is special, in
that it is completely untainted by the camera's software and is a lossless
format, which is to say that there is no tradeoff in image quality - it's
the best your camera can do.

The other 4 compression settings use JPEG, which uses some clever techniques
to compress the image. In short, the lower the quality setting on JPEG, the
more artifacts/blurring you get on the image - especially around straight
lines. On very low quality settings, JPEGs can look really awful.

I'm assuming that since you're shooting in 2MP, you don't want to enlarge
your images, so you might want to try playing with Fine and Normal and see
if you can tell the difference. Whether you can will depend on a) your
output format (paper/web), b) your eyes and c) what kind of processing you
are doing to the image after it comes into the computer.

It makes little sense to shoot at 5MP/Basic (you can't polish a turd) and
unless you want to prepare top quality web images, rarely makes sense to
shoot VGA/Hi.

As other people have been fast to say, it goes without saying that if you
want the best quality or if you want to enlarge the images, shoot in RAW at
5MP. But I suspect that's not your question anyhow.

Regards.

John


 
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Ron G
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Posts: n/a
 
      08-03-2004

Right on...

To use the Mercedes analogy, made earlier in this thread, just because
you can drive at 90 mph with ease and comfort doesn't mean
you have to. Or if you have a camera with a 1.2 lens that you should
always shoot wide open....It's great to buy the best camera you can
afford and then learn to shape it to your needs as a PHOTOGRAPHER
conscious of cost/quality and other issues. I generally know when a
photo I'm taking should be done at the highest possible resolution -- it
may be the one in a thousand or so that I would choose to print at
larger than 5x7. I also know that the odds are very high that I can
still get a 5x7 or 8x10 out of one taken mistakenly at lower res by
judiciously working with Elements. The nice thing about digital
photography is that you can practice, practice, practice and I dare say
that an afternoon fiddling with various settings will show what's best
for you and your budget -- thinking about extra memory cards, maybe a
storage device, etc. etc. I think we need more discussion about how,
creatively (not technically), we can improve on what we do to make up
for less than the highest resolution. Thinking along those lines will
make one a better photographer.


>The resolution and quality work hand in hand and relate to what your usage
>of the images is going to be. The resolution is simple, just the size of the
>output file. The bigger it is, the bigger the image can be enlarged.
>
>The compression is all about the type of output file. RAW is special, in
>that it is completely untainted by the camera's software and is a lossless
>format, which is to say that there is no tradeoff in image quality - it's
>the best your camera can do.
>
>The other 4 compression settings use JPEG, which uses some clever techniques
>to compress the image. In short, the lower the quality setting on JPEG, the
>more artifacts/blurring you get on the image - especially around straight
>lines. On very low quality settings, JPEGs can look really awful.
>
>I'm assuming that since you're shooting in 2MP, you don't want to enlarge
>your images, so you might want to try playing with Fine and Normal and see
>if you can tell the difference. Whether you can will depend on a) your
>output format (paper/web), b) your eyes and c) what kind of processing you
>are doing to the image after it comes into the computer.
>
>It makes little sense to shoot at 5MP/Basic (you can't polish a turd) and
>unless you want to prepare top quality web images, rarely makes sense to
>shoot VGA/Hi.
>
>As other people have been fast to say, it goes without saying that if you
>want the best quality or if you want to enlarge the images, shoot in RAW at
>5MP. But I suspect that's not your question anyhow.
>
>Regards.
>
>John
>
>
>
>


 
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David J Taylor
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Posts: n/a
 
      08-03-2004
>> It makes little sense to shoot at 5MP/Basic (you can't polish a
>> turd) and unless you want to prepare top quality web images, rarely
>> makes sense to shoot VGA/Hi.


You need to test this for the particular camera/display/printer
combination you are using. If the file size is important to you, and you
are shooting at the highest resolution (which I recommend), then the extra
quality obtained by using Normal or Fine compression may only be worth it
in limited circumstances. By doing your own tests, you will know what you
actually need.

Cheers,
David


 
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Arty Phacting
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Posts: n/a
 
      08-03-2004
uh-hu aahh-hhooo-aaahhh aahh-hhhooo-aaahh BS detector alert

JPEG was designed to do a job
It does it very well indeed. In fact it has being doing so well that there
is no known replacement for it!

So, what was that job?

Basically to take a huge bitmap or image file and compress it using
sophisticated algorirthms so an image may be displayed at a PRESET quality
at a PRESET image size.

This it does, this it does well, very well.

But if you zoom in to an 800 x 600 pixel image at 800% don't be surprised if
it looks sorta lumpy.

If the original intention was to show the image at a mega-size then there
are ways to go about that.

Sometimes JPEG is called lossy. Well, maybe tis so. But it only chucks out
what was asked of it to chuck out.

Ask yourself: why are there so many image file formats out there?
Ans: because they all have different jobs to do

'Nuff said

Arts

"John Appleby" <(E-Mail Removed)> wrote in message
news:410f82b8$0$78518$(E-Mail Removed)...
> "Lowryter" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > OK OK, I just got this Nikon 5700, and I have been experimenting, but

> haven't
> > made any prints.
> >
> > Now this a 5 Megapixel Camera. that controls the Megapixel by: Full,

> UXGA,
> > SXGA, XGA, VGA, this equates to print size.
> >
> > but then the compression is goes from Raw, HI, Fine, Normal, & Basic....
> >
> > can someone give me a simple understanding of the trade off
> >
> > the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what

> happens
> > when you increase one over another?
> >
> > yes, it might be a dumb question......

>
> The resolution and quality work hand in hand and relate to what your usage
> of the images is going to be. The resolution is simple, just the size of

the
> output file. The bigger it is, the bigger the image can be enlarged.
>
> The compression is all about the type of output file. RAW is special, in
> that it is completely untainted by the camera's software and is a lossless
> format, which is to say that there is no tradeoff in image quality - it's
> the best your camera can do.
>
> The other 4 compression settings use JPEG, which uses some clever

techniques
> to compress the image. In short, the lower the quality setting on JPEG,

the
> more artifacts/blurring you get on the image - especially around straight
> lines. On very low quality settings, JPEGs can look really awful.
>
> I'm assuming that since you're shooting in 2MP, you don't want to enlarge
> your images, so you might want to try playing with Fine and Normal and see
> if you can tell the difference. Whether you can will depend on a) your
> output format (paper/web), b) your eyes and c) what kind of processing you
> are doing to the image after it comes into the computer.
>
> It makes little sense to shoot at 5MP/Basic (you can't polish a turd) and
> unless you want to prepare top quality web images, rarely makes sense to
> shoot VGA/Hi.
>
> As other people have been fast to say, it goes without saying that if you
> want the best quality or if you want to enlarge the images, shoot in RAW

at
> 5MP. But I suspect that's not your question anyhow.
>
> Regards.
>
> John
>
>



 
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Marvin Margoshes
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Posts: n/a
 
      08-04-2004

"David J Taylor" <(E-Mail Removed)-this-bit.nor-this-part.uk>
wrote in message news:3sGPc.294$(E-Mail Removed)...
> Lowryter wrote:
> > OK OK, I just got this Nikon 5700, and I have been experimenting,
> > but haven't made any prints.
> >
> > Now this a 5 Megapixel Camera. that controls the Megapixel by: Full,
> > UXGA, SXGA, XGA, VGA, this equates to print size.
> >
> > but then the compression is goes from Raw, HI, Fine, Normal, &
> > Basic....
> >
> > can someone give me a simple understanding of the trade off
> >
> > the Combo I am using is SXGA (about 2 Megapixel) and Normal,,,,what
> > happens when you increase one over another?
> >
> > yes, it might be a dumb question......

>
> There are plenty of places you can read about this. My own experience
> shows that if you need to compromise on file size (perhaps the only reason
> for not taking all pictures at Full resolution, Fine quality), is that you
> should keep the Full resolution (2560 x 1920 pixels), but step down from
> Fine to Normal or even Basic in the compression settings. Take the same
> picture on three different quality settings and see if you can tell the
> difference.
>


I agree that is the best way to decide. But one set of photos isn't enough.
Try different kinds of scenes. After all, it doesn;t cost anything - unless
you like the pictures enough to make prints.
> Cheers,
> David
>
>



 
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