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Compression in JPEG files in digital cameras



 
 
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  #31  
Old August 22nd 07, 01:42 PM posted to rec.photo.digital
Thomas T. Veldhouse
external usenet poster
 
Posts: 962
Default Compression in JPEG files in digital cameras

HEMI-Powered wrote:
OK, but again, Thomas, I interpreted the OP as being a fairly new
digital owner and thus a novice on file types, so I just
mentioned TIFF as an alternative if their camera supports it.
TIFF is universally recognized, although news readers cannot
decode it in line, and about its only drawback other than large
size is that if you want to save EXIF, you cannot use LZW
compression, or at least AFAIK.


Hardly any cameras support TIFF. Yes, you can use EXIF with LZW ... the are
completely unrelated as far as TIFF is concerned.

I don't want to start yet another religious war about bit-length.
It seems to me, though, that 16-bit color - no matter where it
comes from or in what format(s) it is saved to - is a subject for
VERY advanced people who have software that can correctly
manipulated it. And, the person behind the camera and behind the
keyboard also has to be quite a bit more knowledgeable to gain
any real advantage over 8-bit.


It doesn't take VERY advanced to use 16-bit. Anybody who wants to shoot
camera RAW should understand a workflow that [potentially] uses 16-bit image
manipulation.


But, I have a question for you Thomas: everytime 16-bit color
comes up, part of the raging debate is that most/all cameras and
apps, including PS CS2, really only have 11 or 12 bits of real
information, the others being basically just noise that is
ignorned by the software. Has that improved in ANY format,
whether it be JPEG, TIFF, or RAW? i.e., is something closer to
16-bit or true 16-bit now available for them with deep pockets?
If so, could you just give me 25 words or less as a heads-up on
today's status so I can go looking? Yes, I know Google is my best
friend, but on things like this, it is like the old saying "I
don't even know enough to ask an intelligent question", and it
goes to the extreme frustration I have had for well over a year
trying to find a RAW for Dummies kind of book that isn't keyed to
PS CS2 or Elements that will at least get me started up the
learning curve.


You don't get more information by converting a 12-bit RAW file to a 16-bit
TIFF (or PSD). You would definitely lose information if you converted to an
8-bit TIFF and you would lose even more information if you converted to an
8-bit JPEG (all JPEG images are 8-bit). As far as the benefits of a 16-bit
workflow, I will leave that for another discussion which has been hashed about
here before and is available in many books and online resources.


In any event, I find these threads fascinating but always feel
bad for the poor OP who has some simple or easy question like
he does the size of the image or compression cause image
problems? I kinda doubt that level of knowledge is ready for all
of the sophisticated answers the more experienced folks have been
bantering about. Yes, /I/ learn something, but a rank novice just
gets totally snowed under and may feel so intimidated as to not
even come back for a 2nd round of questions.


The simple answer to a "simple" question is "yes". But, if you want to know
why, then you have to read.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

  #32  
Old August 23rd 07, 04:21 AM posted to rec.photo.digital
HEMI-Powered[_2_]
external usenet poster
 
Posts: 447
Default Compression in JPEG files in digital cameras

Thomas T. Veldhouse added these comments in the current
discussion du jour ...

Hardly any cameras support TIFF. Yes, you can use EXIF with
LZW ... the are completely unrelated as far as TIFF is
concerned.


I stand/sit corrected, Thomas! I just tried an LZW TIFF from PSP
9. It gave me a warning that no EXIF would be saved, but in fact,
it was. I reopened it and all my Rebel data was there along with
a comment to an editable field. Thanks for letting me know about
this- I always stopped when I saw the warning.

I don't want to start yet another religious war about
bit-length. It seems to me, though, that 16-bit color - no
matter where it comes from or in what format(s) it is saved
to - is a subject for VERY advanced people who have software
that can correctly manipulated it. And, the person behind the
camera and behind the keyboard also has to be quite a bit
more knowledgeable to gain any real advantage over 8-bit.


It doesn't take VERY advanced to use 16-bit. Anybody who
wants to shoot camera RAW should understand a workflow that
[potentially] uses 16-bit image manipulation.


I said I don't want to start any religious wars, and I will not.
But, going from 8-bit software to 16-bit costs money I don't want
to spend, and my personal skill level is woefully inadequate to
know what to do with 16-bit, much less RAW.

In this NG, people run the gamut from rank novices to very
advanced amateurs to pros, with all types and prices of cameras,
and software as simple as Irfanview or as complex, expensive, and
difficult to learn as PS CS. So, /I/ do not think that making the
jump to either 16-bit or RAW is at all trivial. I take nothing
away from you or anyone who's mastered it, but sometimes we
humans forget the difficulties we had the the steepness of the
learning curve. I would've long ago gone to RAW if I could find
even ONE book that explained how to properly use it that was NOT
aimed specifically at PhotoShop. There is no straight-forward way
I know of to translate the workflow into PSP 9. I do not like how
Corel mangled PSP X and PSP XI, so have not gone to them. I will
probably cut over to PS Elements when I get my next computer, but
that most likely is a year away.

So, I would ask you or anyone implying that 16-bit and RAW are
simple to learn to consider the needs, wants, and time budget of
us lesser homo sapiens. Thank you.

But, I have a question for you Thomas: everytime 16-bit color
comes up, part of the raging debate is that most/all cameras
and apps, including PS CS2, really only have 11 or 12 bits of
real information, the others being basically just noise that
is ignorned by the software. Has that improved in ANY format,
whether it be JPEG, TIFF, or RAW? i.e., is something closer
to 16-bit or true 16-bit now available for them with deep
pockets? If so, could you just give me 25 words or less as a
heads-up on today's status so I can go looking? Yes, I know
Google is my best friend, but on things like this, it is like
the old saying "I don't even know enough to ask an
intelligent question", and it goes to the extreme frustration
I have had for well over a year trying to find a RAW for
Dummies kind of book that isn't keyed to PS CS2 or Elements
that will at least get me started up the learning curve.


You don't get more information by converting a 12-bit RAW file
to a 16-bit TIFF (or PSD). You would definitely lose
information if you converted to an 8-bit TIFF and you would
lose even more information if you converted to an 8-bit JPEG
(all JPEG images are 8-bit). As far as the benefits of a
16-bit workflow, I will leave that for another discussion
which has been hashed about here before and is available in
many books and online resources.


You didn't quite answer my question. What I am curious about is
if any cameras or scanners can output a FULL 16-bit color bitmap
and are there any apps that can process all 16 across their
entire function/tool/feature set. I understand the loss if a 12-
bit RAW is downgraded to 8-bit anything, especially JPEG, so I'm
still in inquisative mode.

Now, I have never met anyone who didn't think their own pictures
could be made better. I've not asked you, but then, we don't know
each other well. But, I use both the 80/20 Rule and the Law of
Diminshing Returns to govern how much time and effort to devote
to any editing task. Some of my car pictures are easy enough to
do in a few minutes, most are in the 15-20 minute range, and a
sizable enough number get into 30, 60, more. Since I am a
documentary rather than a creative or artistic photographer of
cars, I have many other interests than spending all day on a
small series of cars shot at an outdoor show or museum with or
without flash. Again, people hereabouts run a really wide gamut
of skills, but much more importantly, not everybody wants, much
less needs, all the sophistication. My daughter, for example,
does just a quicky crop and resame down and takes here SD card to
Meijer to print 4x6. That's all she wants. I can't argue with her
logic even though I disagree because she's an adult who has the
freedom to do what she pleases with her time and money.

In any event, I find these threads fascinating but always
feel bad for the poor OP who has some simple or easy question
like he does the size of the image or compression cause
image problems? I kinda doubt that level of knowledge is
ready for all of the sophisticated answers the more
experienced folks have been bantering about. Yes, /I/ learn
something, but a rank novice just gets totally snowed under
and may feel so intimidated as to not even come back for a
2nd round of questions.


The simple answer to a "simple" question is "yes". But, if
you want to know why, then you have to read.

/I/ know that both size and compression have a greater or lesser
effect on final technical quality, but did the OP in this thread?
His OP was down so low in the grass, he wanted just a simple
recommendation as to how to start taking "good" pictures, and
never came back - I don't think - to even clarify his criteria
for "good".

--
HP, aka Jerry
  #33  
Old August 23rd 07, 04:30 AM posted to rec.photo.digital
HEMI-Powered[_2_]
external usenet poster
 
Posts: 447
Default Compression in JPEG files in digital cameras

David J Taylor added these comments in the current discussion du
jour ...

Both ordinary JPEG and TIFF are both 8-bit. I only mentioned
TIFF, either the uncompressed kind or LZW, as an alternative
to the OP or any lurkers who want a simpler lossless file
system than RAW,


OK, I appreciate that.


David, occasionally, I save to simple Windows BMP or maybe PNG,
and on rare occasions, I will save to PSP's proprietary pspimage
format. Which goes to my constand wonder if the OP ever gets much
out of a thread when it suddenly gets quite technical, well into
theory and away from pragmatics, and we all have fun but I think
they shake their head and slink away. Can't prove that, I just
"feel" it.

Yes, David, as recently as this spring as I was getting ready
for the summer car show season. It isn't that I dispute you
at all, you're much more skilled and knowledgeable than me,
it is that MY experience shows that the amount of work
necessary to get an 8 MP image down to my 1.5 MP finished
size without introducing aliasing and other undesirable
non-compression artifacts just isn't worth my time and
effort.

I never revisited the lower quality, i.e., higher
compression, option on my Rebel because I could easily see
JPEG compression artifacts at a large enough percentage that
I didn't want to risk blowing otherwise good pictures. As you
and others have so correctly pointed out, memory is so cheap,
that it really doesn't matter if the image is 500KB or one
meg.


Yes, I would expect that when using less than the native
resolution of the camera, the images will be slightly sharper
(meaning that there are fewer pixels covering a black-white
transition), and therefore more likely to show JPEG artefacts
at a particular compression (quality) level. So when using
lower resolution, stick with the highest JPEG quality. Makes
sense to me, anyhow!

Again, not for you David because you understand what I try to do
and why, but for them lurkers, about 99 44/100% of my images are
only displayed with a screensaver or slide show in Windows and/or
posted to Usenet. That is why I seldom save larger than 1400 x
1050 and never larger than 1600 x 1200. That said, I'm well aware
of what happens with that low a PPI trying to print to borderless
8.5 x 11 glossy paper, but it does satisfy my needs. And, I have
found that Windows and common slide show programs that "pixel
resize" rather than mathematically "resample" for speed of
display totally mangles an image much larger than my current 1280
x 960 monitor. Now, I do have plans to upgrade to a 24" or 26"
LCD about the time I get my next PC built, maybe late next year,
so I will experiment with the higher resolutions images at that
time.

One other comment wrt posting to Usenet. I simply do not have the
time to save at a large size for myself but resample smaller to
post, therefore I also do not have the time and energy to "do it
right" so as to minimize inevitible aliasing of fine details on
the chrome, badgees, and character lines of my car pictures in
order to meet NG FAQs. It all boils down to this: each of us
should do what works best for us, and I believe you support that
notion. I do stray into "contrarian" mode with novices, though,
because I can tell by their meager OP that they've been snared by
the marketing hype that more mega pixels means better pictures,
without regard to the dozens of other factors involved.

Thanks for your observations and have a great week!

--
HP, aka Jerry
  #34  
Old August 23rd 07, 02:03 PM posted to rec.photo.digital
Thomas T. Veldhouse
external usenet poster
 
Posts: 962
Default Compression in JPEG files in digital cameras

HEMI-Powered wrote:

I said I don't want to start any religious wars, and I will not.
But, going from 8-bit software to 16-bit costs money I don't want
to spend, and my personal skill level is woefully inadequate to
know what to do with 16-bit, much less RAW.

In this NG, people run the gamut from rank novices to very
advanced amateurs to pros, with all types and prices of cameras,
and software as simple as Irfanview or as complex, expensive, and
difficult to learn as PS CS. So, /I/ do not think that making the
jump to either 16-bit or RAW is at all trivial. I take nothing
away from you or anyone who's mastered it, but sometimes we
humans forget the difficulties we had the the steepness of the
learning curve. I would've long ago gone to RAW if I could find
even ONE book that explained how to properly use it that was NOT
aimed specifically at PhotoShop. There is no straight-forward way
I know of to translate the workflow into PSP 9. I do not like how
Corel mangled PSP X and PSP XI, so have not gone to them. I will
probably cut over to PS Elements when I get my next computer, but
that most likely is a year away.


I didn't say it was trivial. I said it doesn't require the user to be
advanced. My daughter was using my computer with Adobe Lightroom on it and
she picked up how to use it on her own. She is 14 and by no means a computer
whiz. Further, she did it without my help, as she was editting [JPEG] files
she took on her P&S. However, working with RAW and 16-bit in this
environment is nearly transparent.

So, I would ask you or anyone implying that 16-bit and RAW are
simple to learn to consider the needs, wants, and time budget of
us lesser homo sapiens. Thank you.


I never once used the words "simple to learn". I said you don't have to be
advanced. There are plenty of books out there on RAW workflow that are pretty
good, and you are free to read them. Further, there are many websites as
well, which are free for your viewing pleasure.

You didn't quite answer my question. What I am curious about is
if any cameras or scanners can output a FULL 16-bit color bitmap
and are there any apps that can process all 16 across their
entire function/tool/feature set. I understand the loss if a 12-
bit RAW is downgraded to 8-bit anything, especially JPEG, so I'm
still in inquisative mode.


The image is FULL 16-bit color. The ADC and source sensor may or may not be
16-bit. Most modern DSLR source at 12-bit and a couple new ones claim 14-bit.
My old Nikon Coolscan had a 14-bit ADC in it as well, but 16-bit was available
for a premium. Moving from 12-bit to 16-bit should incur no loss, and indeed,
it offers additional room for manipulation (so it is even worthwhile to
convert 8-bit to 16-bit and then do your manipulations and finally convert
back to 8-bit for printing or what have you).

Now, I have never met anyone who didn't think their own pictures
could be made better. I've not asked you, but then, we don't know
each other well. But, I use both the 80/20 Rule and the Law of
Diminshing Returns to govern how much time and effort to devote
to any editing task.


I tend to preprocess in groups. I went out to the Bad Lands of South Dakota
last June followed by the Black Hills. I processed all the photos from a
given session at one time in just a couple of minutes. Then I look for photos
that I might like to further work with. That often happens months later BTW.
I find the photo of interest and look more closely, perhaps correct for
chromatic aberation if it exists, exposure, color, curves. I might even get
more creative and create a composite or do some HDR work sourcing from several
frames. My point though, is that the initial processing is usually quite fast
and pretty high level.

Some of my car pictures are easy enough to
do in a few minutes, most are in the 15-20 minute range, and a
sizable enough number get into 30, 60, more. Since I am a
documentary rather than a creative or artistic photographer of
cars, I have many other interests than spending all day on a
small series of cars shot at an outdoor show or museum with or
without flash. Again, people hereabouts run a really wide gamut
of skills, but much more importantly, not everybody wants, much
less needs, all the sophistication. My daughter, for example,
does just a quicky crop and resame down and takes here SD card to
Meijer to print 4x6. That's all she wants. I can't argue with her
logic even though I disagree because she's an adult who has the
freedom to do what she pleases with her time and money.


Sounds like you are in need of a workflow. Again, I suggest a good book, but
won't suggest a specific book to you at this time. I recommend you consider
a RAW workflow as well, but that is up to you.

/I/ know that both size and compression have a greater or lesser
effect on final technical quality, but did the OP in this thread?
His OP was down so low in the grass, he wanted just a simple
recommendation as to how to start taking "good" pictures, and
never came back - I don't think - to even clarify his criteria
for "good".


Perhaps he read what he needed and just lurks. Usenet threads often mutate
and that is an expected occurance on USENET (or any threaded forum).

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

  #35  
Old August 23rd 07, 04:55 PM posted to rec.photo.digital
HEMI-Powered[_2_]
external usenet poster
 
Posts: 447
Default Compression in JPEG files in digital cameras

Thomas T. Veldhouse added these comments in the current
discussion du jour ...

I didn't say it was trivial. I said it doesn't require the
user to be advanced. My daughter was using my computer with
Adobe Lightroom on it and she picked up how to use it on her
own. She is 14 and by no means a computer whiz. Further, she
did it without my help, as she was editting [JPEG] files she
took on her P&S. However, working with RAW and 16-bit in this
environment is nearly transparent.


There's an old saying that covers my view on this: "the algorithm
to solve this problem or that one is straigt-forward but not
trivial. So, I would submit that if what you learned through the
school of hard knocks you readily admit isn't trivial, it likely
also is not for novices or the faint of heart.

So, I would ask you or anyone implying that 16-bit and RAW
are simple to learn to consider the needs, wants, and time
budget of us lesser homo sapiens. Thank you.


I never once used the words "simple to learn". I said you
don't have to be advanced. There are plenty of books out
there on RAW workflow that are pretty good, and you are free
to read them. Further, there are many websites as well, which
are free for your viewing pleasure.


I have scoured my local bookstores and their on-line stores
looking for exactly what you describe, but every one I've come
across so far assumes I have either PS CS or PS Elements, while I
have PSP 9 and like it. So, workflow tutorials would be quite
helpful to me, but NOT when they are illustrated with photographs
shot off a PhotoShop screen with the steps involved. I also have
the last version of Raw Shooter Premium before Adobe bought them,
killed it, and launched Lightroom. It has these really nifty 89-
page manual, but it is a reference manual and assumes I already
know what I want to do and why and simply tells me what tools I
want. What it is NOT is a leg-up on the learning curve, which I
find so steep that RAW is outside the range of my radar and sonar
for time management reasons.

You didn't quite answer my question. What I am curious about
is if any cameras or scanners can output a FULL 16-bit color
bitmap and are there any apps that can process all 16 across
their entire function/tool/feature set. I understand the loss
if a 12- bit RAW is downgraded to 8-bit anything, especially
JPEG, so I'm still in inquisative mode.


The image is FULL 16-bit color. The ADC and source sensor may
or may not be 16-bit. Most modern DSLR source at 12-bit and a
couple new ones claim 14-bit. My old Nikon Coolscan had a
14-bit ADC in it as well, but 16-bit was available for a
premium. Moving from 12-bit to 16-bit should incur no loss,
and indeed, it offers additional room for manipulation (so it
is even worthwhile to convert 8-bit to 16-bit and then do your
manipulations and finally convert back to 8-bit for printing
or what have you).


Excuse my denseness, but a "full" 16-bit image of which only 12
or 14 bits are usuable, is NOT what I meant. You just confirmed
my supposition, nobody is yet actually producing images that have
legitimate data in all 16 bits.

Now, I have never met anyone who didn't think their own
pictures could be made better. I've not asked you, but then,
we don't know each other well. But, I use both the 80/20 Rule
and the Law of Diminshing Returns to govern how much time and
effort to devote to any editing task.


I tend to preprocess in groups. I went out to the Bad Lands
of South Dakota last June followed by the Black Hills. I
processed all the photos from a given session at one time in
just a couple of minutes. Then I look for photos that I might
like to further work with. That often happens months later
BTW. I find the photo of interest and look more closely,
perhaps correct for chromatic aberation if it exists,
exposure, color, curves. I might even get more creative and
create a composite or do some HDR work sourcing from several
frames. My point though, is that the initial processing is
usually quite fast and pretty high level.


What can I say? You're obviously better/faster than I am. I
applaud you for that skill, I simply don't have it and many of my
friends who are fellow car show and musueum photographers are in
about the same boat as I am.

Some of my car pictures are easy enough to
do in a few minutes, most are in the 15-20 minute range, and
a sizable enough number get into 30, 60, more. Since I am a
documentary rather than a creative or artistic photographer
of cars, I have many other interests than spending all day on
a small series of cars shot at an outdoor show or museum with
or without flash. Again, people hereabouts run a really wide
gamut of skills, but much more importantly, not everybody
wants, much less needs, all the sophistication. My daughter,
for example, does just a quicky crop and resame down and
takes here SD card to Meijer to print 4x6. That's all she
wants. I can't argue with her logic even though I disagree
because she's an adult who has the freedom to do what she
pleases with her time and money.


Sounds like you are in need of a workflow. Again, I suggest a
good book, but won't suggest a specific book to you at this
time. I recommend you consider a RAW workflow as well, but
that is up to you.


Do not asssume I have no workflow. I clearly do. In fact, to help
friends that are just getting into digital photography, I have
codified my workflow into 10 basic steps and about 3 pages of
text. Just because I have a finite algorithm - the workflow -
does NOT even begin to address the issues that confront me that
take far longer. Perhaps the biggest problem stems from extremes
in dynamic range tonal characteristics across the entire car or
key parts of it. Simply doing a 5 minute global tweak doesn't cut
it. If it did, I'd have cut my workflow to just 2 or 3 steps and
been a lot happier than I am.

NO, I am simply NOT going to spend time and effort, both of which
are in very short supply with me, beating my head against a stone
wall because people in this NG like RAW so much they become
zealots. I understand the fundamental concepts and why it is
better, but you and several others need to understand that not
everybody is cut out for that.

/I/ know that both size and compression have a greater or
lesser effect on final technical quality, but did the OP in
this thread? His OP was down so low in the grass, he wanted
just a simple recommendation as to how to start taking "good"
pictures, and never came back - I don't think - to even
clarify his criteria for "good".


Perhaps he read what he needed and just lurks. Usenet threads
often mutate and that is an expected occurance on USENET (or
any threaded forum).

I think the OP here, like so many, got completely blown away from
my middle-ground technical discussions and yours, blowing him out
to sea with wild stories about 16-bit color and RAW when all he
likely wants to do is what my daughter does - just get a fairly
decent 4 x 6 prints at Meijer, she simply isn't at all interested
in being an accomplished digital photographer. So, what would you
say to her, that's she's just as stupid and stubborn as I am just
because we have alternative views from your own? Surely some of
the advanced people in this NG that get into the range of what I
call elitists and image bigots must recognize that there isn't
one right way to do things, there are literally hundreds of ways.

EOT.

--
HP, aka Jerry
  #36  
Old August 23rd 07, 05:48 PM posted to rec.photo.digital
Thomas T. Veldhouse
external usenet poster
 
Posts: 962
Default Compression in JPEG files in digital cameras

HEMI-Powered wrote:

There's an old saying that covers my view on this: "the algorithm
to solve this problem or that one is straigt-forward but not
trivial. So, I would submit that if what you learned through the
school of hard knocks you readily admit isn't trivial, it likely
also is not for novices or the faint of heart.


I didn't have any trouble learning how to do it. I have drawn on several
online resources and browsed a couple of books to get ideas on how to
streamline my approach, but there was no attendance at the "school of hard
knocks".

Have it your way ... it is extremely difficult, not for the faint of heart and
everybody [except extremely advanced individuals, such as myself] should just
simply use JPEG ;-)

I have scoured my local bookstores and their on-line stores
looking for exactly what you describe, but every one I've come
across so far assumes I have either PS CS or PS Elements, while I
have PSP 9 and like it. So, workflow tutorials would be quite
helpful to me, but NOT when they are illustrated with photographs
shot off a PhotoShop screen with the steps involved. I also have
the last version of Raw Shooter Premium before Adobe bought them,
killed it, and launched Lightroom. It has these really nifty 89-
page manual, but it is a reference manual and assumes I already
know what I want to do and why and simply tells me what tools I
want. What it is NOT is a leg-up on the learning curve, which I
find so steep that RAW is outside the range of my radar and sonar
for time management reasons.


You have to have a RAW converter, and as such, it requires a workflow that
uses it. The workflow using the RAW converter in PSP will be different than
the workflow using the RAW converter in Adobe Lightroom and yet again
different the using the RAW converter in PS and Bridge.

You know what? You have the same issue with JPEG. You need to establish a
workflow, plain and simple. You will find as many opinions on the best
workflow as there are people who have opinions on workflow. Everybody will do
it differently.

Excuse my denseness, but a "full" 16-bit image of which only 12
or 14 bits are usuable, is NOT what I meant. You just confirmed
my supposition, nobody is yet actually producing images that have
legitimate data in all 16 bits.


Yes they are. Nikon Coolscan scanners are available that are 16-bit (some
lower scale images are 14-bit). More important than a 16-bit image is a
16-bit workflow. You want more data to work with and the reason should be
obvious at this point. Having the room to work with it is why a 16-bit
workflow has advantages over an 8-bit workflow.

What can I say? You're obviously better/faster than I am. I
applaud you for that skill, I simply don't have it and many of my
friends who are fellow car show and musueum photographers are in
about the same boat as I am.


You know, I am not sure where you are trying to go with this thread. Perhaps
you want to legitimize your approach by minimizing the 16-bit workflow
including RAW that I mention. Be my guest. But I don't think this thread has
progressed, so I am departing it.

I think the OP here, like so many, got completely blown away from
my middle-ground technical discussions and yours, blowing him out
to sea with wild stories about 16-bit color and RAW when all he
likely wants to do is what my daughter does - just get a fairly
decent 4 x 6 prints at Meijer, she simply isn't at all interested
in being an accomplished digital photographer. So, what would you
say to her, that's she's just as stupid and stubborn as I am just
because we have alternative views from your own? Surely some of
the advanced people in this NG that get into the range of what I
call elitists and image bigots must recognize that there isn't
one right way to do things, there are literally hundreds of ways.


Ask the OP's opinion on the matter. The thread moved on, as they usually do
on USENET and does not and should not be constrained to a scope arbitrarily
imposed by you.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

  #37  
Old August 23rd 07, 06:10 PM posted to rec.photo.digital
Bill Tuthill
external usenet poster
 
Posts: 361
Default Compression in JPEG files in digital cameras

HEMI-Powered wrote:

I never revisited the lower quality, i.e., higher compression,
option on my Rebel because I could easily see JPEG compression
artifacts at a large enough percentage that I didn't want to risk
blowing otherwise good pictures. As you and others have so
correctly pointed out, memory is so cheap, that it really doesn't
matter if the image is 500KB or one meg.


Could you please post an impage where you can easily see JPEG artifacts
at the highest quality your Rebel produces? Thanks!

The reason I ask is, it's hard for me to see JPEG artifacts at Q 95
and 1x1 or 2x1 chroma subsampling, and I'm good at seeing JPEG artifacts.

  #38  
Old August 23rd 07, 07:34 PM posted to rec.photo.digital
HEMI-Powered[_2_]
external usenet poster
 
Posts: 447
Default Compression in JPEG files in digital cameras

Thomas T. Veldhouse added these comments in the current
discussion du jour ...

Have it your way ... it is extremely difficult, not for the
faint of heart and everybody [except extremely advanced
individuals, such as myself] should just simply use JPEG ;-)


This is a fair statement and I respect you for recognizing that
not everone can be a superstar. I also appreciate some
corroboration that it is indeed some sort of "advanced"
individual who makes the jump from ordinary JPEG to 16-bit or to
RAW.

You know, I am not sure where you are trying to go with this
thread. Perhaps you want to legitimize your approach by
minimizing the 16-bit workflow including RAW that I mention.
Be my guest. But I don't think this thread has progressed, so
I am departing it.


I am not on any kind of soapbox except the First Amendment one
which give me the freedom and rights to do what I think is best
for me, as you do what is best for you, and all the others do the
same.

Ask the OP's opinion on the matter. The thread moved on, as
they usually do on USENET and does not and should not be
constrained to a scope arbitrarily imposed by you.


I don't seek out OPs. If, for any reasons good or bad they choose
not to come back in and provide more details on what they want to
do and why or to simply say "hey, guys, you're having a great
time but you've over my head, can you please tone it down some
and just get me over the hump to some reasonable prints of my
vacation this summer?" If the OP cannot or will not do that,
there isn't much any of us across any skill level can do to help
them.

And, I understand quite well, thank you, the way that threads
have a life of their own and I am attempting NO imposition of my
views, except when /I/ have a question or I feel I must defend my
honor. That has nothing at all to do with the OP who should take
care of themselves. I will say this, though, it is a rare, rare
thread in this or the SLR NG that start off with an innocent
novice OP that don't wind up sooner or later into some sort of
contest where people want to suggest that THEIR methods and
workflows are the only way. Life just isn't that way. I've
explained the purpose I use my images for enough times that I
shan't repeat them here, except to say that in general, I don't
personally give a rip about PPI or contest-quality images because
that isn't my bag. If people cannot deal with that, it is their
problem, not mine. And, so, yet another disagreement is coming to
an end because I am again tired of being harangued for not
wanting to be a Top Gun - the best of the best - when it comes to
digital photography. I more or less live by the motto that
whatever floats your boat is fine by me so long as it doesn't
swamp mine.

--
HP, aka Jerry
  #39  
Old August 23rd 07, 07:40 PM posted to rec.photo.digital
HEMI-Powered[_2_]
external usenet poster
 
Posts: 447
Default Compression in JPEG files in digital cameras

Bill Tuthill added these comments in the current discussion du
jour ...

I never revisited the lower quality, i.e., higher
compression, option on my Rebel because I could easily see
JPEG compression artifacts at a large enough percentage that
I didn't want to risk blowing otherwise good pictures. As you
and others have so correctly pointed out, memory is so cheap,
that it really doesn't matter if the image is 500KB or one
meg.


Could you please post an impage where you can easily see JPEG
artifacts at the highest quality your Rebel produces? Thanks!

The reason I ask is, it's hard for me to see JPEG artifacts at
Q 95 and 1x1 or 2x1 chroma subsampling, and I'm good at
seeing JPEG artifacts.


This isn't a binary NG so I can't post here, but I also do not
keep an accurate inventory of those images I may see artifacts in
out of my camera. And, by the time I have finished with an image,
I have taken the technical steps I think are prudent to eliminate
all but the most minor defects by always re-opening a just-saved
image to check for the two biggies: artifacts as in streaks,
blobs, and blotches, or aliasing, aka jaggies.

Incidently, I don't think I ever said I've seen an artifact in my
Rebel's higher of its two available quality settings. What I said
was that some significant percentage at the lower setting DID
exhibit artifacts. There are many factors involved other than
just pure over compression, but I would hazard a guess that at
the lower quality level I see at least 5% that have damage,
sometimes 10% or more. And, since I cannot predict at the time I
am shooting which 5 or 10% will be damaged, I go for the quality.
Memory is cheap, my time is not.

As to Chroma subsampling, my normal setting is 1x2. I will lower
the compression number and/or change to 1x1 (none) until I can
eliminate the damage as described above.

--
HP, aka Jerry
  #40  
Old August 23rd 07, 07:42 PM posted to rec.photo.digital
Thomas T. Veldhouse
external usenet poster
 
Posts: 962
Default Compression in JPEG files in digital cameras

HEMI-Powered wrote:

This is a fair statement and I respect you for recognizing that
not everone can be a superstar. I also appreciate some
corroboration that it is indeed some sort of "advanced"
individual who makes the jump from ordinary JPEG to 16-bit or to
RAW.


Oh ... for God's sake, it was SARCASM.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

 




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