Image Size and Compression.

"Peter" wrote in message
...
"Tim Conway" wrote in message
...

"Outing Trolls is FUN!" wrote in message
...
On Fri, 30 Jul 2010 09:29:55 -0400, "Peter"

wrote:

"bugbear" wrote in message
news:LridnROBwbkKVs_RnZ2dnUVZ8gKdnZ2d@brightvi ew.co.uk...
Outing Trolls is FUN! wrote:
On Fri, 30 Jul 2010 12:59:32 +0100, Martin Brown
wrote:

For my money the higher resolution image using higher compression
will
almost always beat the lower resolution less compressed image. There
can
be exceptions and unless you are absolutely certain you will never
need
the extra pixels or you are running out of media space there is
little
or no advantage in decreasing image size in the camera.

Regards,
Martin Brown

Showing how little you know.

If using higher ISO's with more noise, it can be advantageous to use
in-camera downsampling. As this will average-out the noise from the
RAW
sensor data.

It would be more "advantageous" to retain the original data
and use a superior noise reduction algorithm later.

You can look up noise reduction algorithms on your own time
if you think averaging is a good one.



the only reason to answer it, is when, as above, it is spreading
misinformation. You are correct. It is not stating that most NR,
including
averaging, works on a principle of blurring. Therefore details will be
lost.

Far less details lost in-camera direct from the sensor data than you
will
get by using the only available algorithm in PhotoSlop being sloppy
last-century's bicubic.

****, are you ever an ignorant moron of a useless **** of a troll.

And you don't have to be so damn rude.



Oh yes it does. Part of it's sickness. That statement coming for it,
should be taken as a compliment.

I know. I know. I just wanted to voice my discontent with it. You would
think that if he really did all those things he says he did in life, he
would also had learned some civility in dealing with fellow humans. I
suppose that's just part of his "sickness". I'm not paying attention to him
anymore.

On 2010-07-30 09:02:22 -0700, "Tim Conway" said:


"Peter" wrote in message
...
"Tim Conway" wrote in message
...

"Outing Trolls is FUN!" wrote in message
...
On Fri, 30 Jul 2010 09:29:55 -0400, "Peter"
wrote:

"bugbear" wrote in message
o.uk...
Outing Trolls is FUN! wrote:
On Fri, 30 Jul 2010 12:59:32 +0100, Martin Brown
wrote:

For my money the higher resolution image using higher compression will
almost always beat the lower resolution less compressed image. There can
be exceptions and unless you are absolutely certain you will never need
the extra pixels or you are running out of media space there is little
or no advantage in decreasing image size in the camera.

Regards,
Martin Brown

Showing how little you know.

If using higher ISO's with more noise, it can be advantageous to use
in-camera downsampling. As this will average-out the noise from the RAW
sensor data.

It would be more "advantageous" to retain the original data
and use a superior noise reduction algorithm later.

You can look up noise reduction algorithms on your own time
if you think averaging is a good one.



the only reason to answer it, is when, as above, it is spreading
misinformation. You are correct. It is not stating that most NR, including
averaging, works on a principle of blurring. Therefore details will be lost.

Far less details lost in-camera direct from the sensor data than you will
get by using the only available algorithm in PhotoSlop being sloppy
last-century's bicubic.

****, are you ever an ignorant moron of a useless **** of a troll.

And you don't have to be so damn rude.



Oh yes it does. Part of it's sickness. That statement coming for it,
should be taken as a compliment.

I know. I know. I just wanted to voice my discontent with it. You
would think that if he really did all those things he says he did in
life, he would also had learned some civility in dealing with fellow
humans. I suppose that's just part of his "sickness". I'm not paying
attention to him anymore.

Agreed, not paying attention to him is the best way to deal with him.
For months now I have not seen his posts. What I see of his, are the
responses of those who respond to his baiting and rants.
None of my remarks related to him, has been a direct response to any of
his posts, only a comment to those who have reacted, as is this post.
They might have provoked a response from him, but who cares.
Anything of value he might have contributed has been tainted by his
psychosis, and his self-inflating "Walter Mittyish" ego rants have no
value at all.

As for the value of anything I might contribute regarding photography,
or other personal opinions I have expressed, I try to limit that to
equipment I own, or knowledge and experience I have gained over the
years.

--
Regards,

Savageduck

Ryan McGinnis wrote:
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On 7/30/2010 9:12 AM, ray wrote:
On Fri, 30 Jul 2010 01:25:37 -0700, bobwilliams wrote:

Let's assume I have a 10MP camera
My sensor is say, 3650 X 2740 pixels. But say I want to create an image
at 1825 x 1370 pixels. How does the camera actually reduce the 5.0MPs to
2.5MPs Does it choose groups of 4 pixels and somehow average them out to
groups of 1 pixel each?
How does this process differ from compressing the 10MP image by a factor
of 4.
I know that in one case the image SIZE is reduced (as well as the file
size) whereas in the other case, the image SIZE remains the same but the
file size is reduced.
How exactly does each process affect the appearance of say an 8x10
print. Bob Williams
I would imagine you are talking about JPEG compression here. Suggest you
experiment a little with your favourite photo manipulation software.
You'll find that most images can be very highly compressed without any
noticeable degredation. The same is not true for dropping resolution.

I'd take a different approach: why try to reduce filesize? Storage is
incredibly cheap and getting cheaper by the hour. If you are not
shooting RAW, a terabyte drive will hold more photos than you're likely
to take in your lifetime on a 10MP camera, and they run around $150.
You can't go back and re-take your photo in a higher resolution or with
less compression, but you can always buy more hard drives.

- --
The op beat me to the same question. My concern was not with file size
but with noise. Canon do use a lower resolution when higher iso is
selected by them for low light scene settings. I'll just run a bunch of
test shots including using the noise reduction layer in PhotoPlus (could
never afford PS).

On Fri, 30 Jul 2010 09:56:21 -0500, Ryan McGinnis wrote:

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Hash: SHA1

On 7/30/2010 9:12 AM, ray wrote:
On Fri, 30 Jul 2010 01:25:37 -0700, bobwilliams wrote:

Let's assume I have a 10MP camera
My sensor is say, 3650 X 2740 pixels. But say I want to create an
image at 1825 x 1370 pixels. How does the camera actually reduce the
5.0MPs to 2.5MPs Does it choose groups of 4 pixels and somehow average
them out to groups of 1 pixel each?
How does this process differ from compressing the 10MP image by a
factor of 4.
I know that in one case the image SIZE is reduced (as well as the file
size) whereas in the other case, the image SIZE remains the same but
the file size is reduced.
How exactly does each process affect the appearance of say an 8x10
print. Bob Williams

I would imagine you are talking about JPEG compression here. Suggest
you experiment a little with your favourite photo manipulation
software. You'll find that most images can be very highly compressed
without any noticeable degredation. The same is not true for dropping
resolution.

I'd take a different approach: why try to reduce filesize? Storage is
incredibly cheap and getting cheaper by the hour. If you are not
shooting RAW, a terabyte drive will hold more photos than you're likely
to take in your lifetime on a 10MP camera, and they run around $150. You
can't go back and re-take your photo in a higher resolution or with less
compression, but you can always buy more hard drives.

I'm not arguing about the cost of storage - I'm answering a question.
There could be any number of reasons to concern oneself with file size -
for one, when you're doing web pages. Huge files can take a long time to
download even with broadband connection - and not EVERYONE has high speed
connections.



- --
- -Ryan McGinnis
The BIG Storm Picture -- http://bigstormpicture.com Vortex-2 image
licensing at http://vortex-2.com Getty:
http://www.gettyimages.com/search/se...=Ryan+McGinnis

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ray wrote:
On Fri, 30 Jul 2010 01:25:37 -0700, bobwilliams wrote:

Let's assume I have a 10MP camera
My sensor is say, 3650 X 2740 pixels. But say I want to create an image
at 1825 x 1370 pixels. How does the camera actually reduce the 5.0MPs to
2.5MPs Does it choose groups of 4 pixels and somehow average them out to
groups of 1 pixel each?
How does this process differ from compressing the 10MP image by a factor
of 4.
I know that in one case the image SIZE is reduced (as well as the file
size) whereas in the other case, the image SIZE remains the same but the
file size is reduced.
How exactly does each process affect the appearance of say an 8x10
print. Bob Williams

I would imagine you are talking about JPEG compression here. Suggest you
experiment a little with your favourite photo manipulation software.
You'll find that most images can be very highly compressed without any
noticeable degredation. The same is not true for dropping resolution.
That is what I have noticed too. I was just wondering how such good
quality was retained after losing so much image information either by
compression or image size reduction.
Bob

"Savageduck" wrote in message
news:2010073009383611272-savageduck1@REMOVESPAMmecom...
On 2010-07-30 09:02:22 -0700, "Tim Conway" said:



As for the value of anything I might contribute regarding photography, or
other personal opinions I have expressed, I try to limit that to equipment
I own, or knowledge and experience I have gained over the years.


If everybody did that we would have far fewer posts, but the reliability of
the advice and the quality of postings would greatly increase. It might even
encourage others with real knowledge to contribute. I suspect that too many
are intimidated by the BS artists/ No. "BSers.


--
Peter

"Dave Cohen" wrote in message
...

The op beat me to the same question. My concern was not with file size but
with noise. Canon do use a lower resolution when higher iso is selected by
them for low light scene settings. I'll just run a bunch of test shots
including using the noise reduction layer in PhotoPlus (could never afford
PS).


Try Corel PaintShop Photo Pro. Corel sells it for $59.9. It is excellent
value and does not have a large learning curve.
In the interests of full disclosure, I am a Corel partner, but only for
WordPerfect.

--
Peter

"bobwilliams" wrote in message
...
[]
That is what I have noticed too. I was just wondering how such good
quality was retained after losing so much image information either by
compression or image size reduction.
Bob

By matching the compression to both the source and the eye/brain
characteristics - i.e. limiting the amount of detail where the eye can't
see it. JPEG is generally very well designed for its intended use.

Cheers,
David

"bobwilliams" wrote in message
...
ray wrote:

I would imagine you are talking about JPEG compression here. Suggest you
experiment a little with your favourite photo manipulation software.
You'll find that most images can be very highly compressed without any
noticeable degredation. The same is not true for dropping resolution.
That is what I have noticed too. I was just wondering how such good
quality was retained after losing so much image information either by
compression or image size reduction.

It depends on the image and viewing method.
As a general rule: (Yes there may be some exceptions, depending on the
particular image.)
If you are talking about digital viewing, you may not even notice the
degradation. If set up for magazine printing, maybe there would be some
noticeable degradation. For photo quality ink jet printing depends on the
size. the larger the print, the more you will notice the degradation.

IOW there is no one definitive answer that fits all cases.
--
Peter

On Fri, 30 Jul 2010 17:08:38 -0400, "Peter"
wrote:

"Savageduck" wrote in message
news:2010073009383611272-savageduck1@REMOVESPAMmecom...
On 2010-07-30 09:02:22 -0700, "Tim Conway" said:



As for the value of anything I might contribute regarding photography, or
other personal opinions I have expressed, I try to limit that to equipment
I own, or knowledge and experience I have gained over the years.


If everybody did that we would have far fewer posts, but the reliability of
the advice and the quality of postings would greatly increase. It might even
encourage others with real knowledge to contribute. I suspect that too many
are intimidated by the BS artists/ No. "BSers.

You mean like yourself? BS-Artists? I've yet to see even ONE valid bit of
information come from you. You lousy ****ing pretend-photographer troll.

LOL!