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What role does size play in quality?

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MikeTTF

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Remember, I'm new to digital photography ... so I'm prone to asking an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution - compression level and sensitivity interact. Someone said that "quality" is in the compression level ---- determined by the "Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72% larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO 100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
 
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
Thanks for the question. I'm still confused with that too.
--
mikl kacz
 
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....
Click to expand...
Thats OK we wuz all newbies once!
MikeTTF said:
Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....
Click to expand...
Economy, Standard and Fine all apply to the level of image compression. The RAW file is about 12MB. Jpeg compression allows "redundant" information in the file to be stripped out and "interpolated" when the picture is recreated - so a patch of blue sky which is all the same colour will be very compressed, whereas a picture of a detailed subject like a tree will not. Much like speech on a digital phone line. Higher compression makes much more approximate decisions about what constitutes the "same" colour, so some subtle details can be lost altogether. Lower compression has a lower tolerance level and preserves more detail. Uncompressed files (TIFF and RAW) make no assumptions at all and give you the lot...

Standard compression is actually pretty good - detail loss over Fine is very slight and noise is lower. Economy mode has more noticeable artifacts around edges and details but is probably OK for smaller prints.

If you edit and save JPEGs repeatedly, they re-compress the image each time - so each save loses more and more detail (what you lost last time, plus what you lose this time). You wont see much difference between each save, but of you do 10 saves and look at the first and last its pretty obvious. So, any image you want to play with in Photoshop, open the JPEG, save it as TIFF or Bitmap, and then edit to your hearts' content.
MikeTTF said:
That got me wondering whether I'm confusing resolution/size with
quality?
Click to expand...
No - they BOTH contribute to quality. Size is the MOST important factor because it dictates the number of pixels in the final image. Compression just dictates the degree to which these pixels are "real" or interpolated.
MikeTTF said:
2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?
Click to expand...
No - its depends entirely on the monitor or printer it is being displayed on. There is no relationship between pixels (dots) and size unless you take the output resolution into account.

So, set your printer resolution to 300 DPI for instance. The size of the print will be 2560/300 inches X 1920/300 inches, or 8.5 X 6.4.

If you want larger prints (say 20") you can either
  • lower the printer resolution (fewer dots per inch --> more inches)
  • expand the image (using interpolation) to give more "dots".
Good interpolation using fractal geometry can actually do quite a good job of inventing the "new" pixels and give quite good results - better than lowering printer res anyway.

If your monitor is running at 1600 X 1200 then at 100% magnification you will see approximately 60% of the image on the screen. However the "size" will simply depend on the screen size.

The resolution setting on EXIF (72 dpi) is just a default number and is not affecting what you se on the screen or what your print. In fact you can ignore it completely!!
MikeTTF said:
If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?
Click to expand...
No - see above - the larger the base image the higher the printer resolution you can set and the better the image. Printers can normally manage about 1400 dpi though this is for all three colours, so really this is more like 500dpi. To get a 10X8" print, just set the printer resolution in PS to 2560 (number of pixels) divided by 10 (size of image) and you get

256 dpi - well within your printer's capability and well above the visible threshold (where you can see the dots).
MikeTTF said:
So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?
Click to expand...
Absolutely not. Effectively you are using a 1.2 MP camera!!

See above. If you shot at 1280 and wanted 10" prints the printer resolution would only be 128dpi, which is low! however if you want to post on the Web, downsizing to this size is advisable because the images are 1/4 the size in MB but still fill the screen!!

Hope this is understandable.

Steve
 
sorry, just couldn't resist

really hope i haven't offended anybody.......
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
 
Mike,

Your question isn't stupid, nor confusing - even though the theme certainly is confusing. I've been in digital for nearly 3 years, and it has taken me nearly that long to get it figured out. So here goes my semi amateur attempt at answering your question. I'll do it in simple steps to help me refresh my own memory and abilities.

Resolution = size in pixels

Quality = compression level (only for jpeg files - TIFF and RAW are not compressed at all, but are too darn big to use in amateur applications)

The size calculation you performed is near perfect, but unfortunately, only applies for the SCREEN. You see, on a computer screen, your images are displayed at 72 dots per inch. On a printer, however, the resolution is closer to 300 dots per inch. So if you were to recalculate your sizes using 300 instead of 72, it almost looks like we're stuck with small print outs. That is not so.

Here is my simple formula (and it is quite conservative):
2mp = 1600x1200 = able up to to print 5x7
3mp = 2048x1536 = able up to to print 8x10
4mp = 2240x1680 = able up to to print 11x14
5mp = 2560x1920 = whatever the next size would be.

Basically what I've said above is the following: With the different megapixel counts, which equal to the resolutions I listed, you can print up to those sizes without any pixelation at all. At these sizes, these pictures will look like they were taken with film. Above that, you begin a gradual pixelation. With that said, I can tell you that I've printed 1600x1200 images at 8x10 with no visible pixelation - just a little softness.

I think that's all on resolution. Compression is a simpler story. Basically, compression is how much the camera manipulates the original file to take it from big to small. The compression has absolutely no bearing on the pixelation. It affects sharpness, detail, crispness. So if you have the card space, always try to shoot best quality = least compression.

Wow, I'm winded. I hope this helps. I must say, it was a good refresher for me too.

Happy shooting, and feel free to ask anything you'd like. I'll always try to help.

Freddy
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
 
The dimensions you're referring to (2560 x 1920 pixels being equivalent to 35 x 26 inches) are based on a 72 ppi (pixels per inch) resolution, which is more or less the typical resolution of a computer monitor. If you intend to print your images and not have them look grainy and rough, you'll want to increase the resolution of the image using a program like Paint Shop Pro or Photoshop before printing it.

The same 2560 x 1920 pixel image that gives you 35 x 26 inches at 72 ppi

will give you an approximately 17.5 inch x 13 inch print at 144 ppi. Depending on your needs, 144 ppi may be high enough resolution to give you a good-looking print. This depends on what printer you're using and what you plan to do with the print.

As a practical example, let's assume you want to take a picture that will give you a 10 inch x 7.5 inch print at a 150 pixels-per-inch resolution. (I'm using 10 x 7.5 to keep the same 4 to 3 aspect ratio). For this print, you will need a 1500 pixel x 1125 pixel original image.

The bottom line of all this is that the larger the print you want to make, and the higher the print resolution you need, the more pixels you want in the original image. If the maximum size image you will be printing is 8 x 10, and your printer's optimum resolution is 150 ppi, you probably don't need to shoot at the 2560 x 190 size.

To complicate things further, if you think you might end up cropping or doing other manipulations of the image in software, you might want those extra pixels to play with.

Hope this helps clear things up more than it confuses!

--Larry
mikl k said:
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
Thanks for the question. I'm still confused with that too.
--
mikl kacz
Click to expand...
 
Steve Jacob said:
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....
Click to expand...
Thats OK we wuz all newbies once!
*isteve said:
Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....
Click to expand...
Economy, Standard and Fine all apply to the level of image
compression. The RAW file is about 12MB. Jpeg compression allows
"redundant" information in the file to be stripped out and
"interpolated" when the picture is recreated - so a patch of blue
sky which is all the same colour will be very compressed, whereas a
picture of a detailed subject like a tree will not. Much like
speech on a digital phone line. Higher compression makes much more
approximate decisions about what constitutes the "same" colour, so
some subtle details can be lost altogether. Lower compression has a
lower tolerance level and preserves more detail. Uncompressed files
(TIFF and RAW) make no assumptions at all and give you the lot...

Standard compression is actually pretty good - detail loss over
Fine is very slight and noise is lower. Economy mode has more
noticeable artifacts around edges and details but is probably OK
for smaller prints.

If you edit and save JPEGs repeatedly, they re-compress the image
each time - so each save loses more and more detail (what you lost
last time, plus what you lose this time). You wont see much
difference between each save, but of you do 10 saves and look at
the first and last its pretty obvious. So, any image you want to
play with in Photoshop, open the JPEG, save it as TIFF or Bitmap,
and then edit to your hearts' content.
*isteve said:
That got me wondering whether I'm confusing resolution/size with
quality?
Click to expand...
No - they BOTH contribute to quality. Size is the MOST important
factor because it dictates the number of pixels in the final image.
Compression just dictates the degree to which these pixels are
"real" or interpolated.
*isteve said:
2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?
Click to expand...
No - its depends entirely on the monitor or printer it is being
displayed on. There is no relationship between pixels (dots) and
size unless you take the output resolution into account.

So, set your printer resolution to 300 DPI for instance. The size
of the print will be 2560/300 inches X 1920/300 inches, or 8.5 X
6.4.

If you want larger prints (say 20") you can either
  • lower the printer resolution (fewer dots per inch --> more inches)
  • expand the image (using interpolation) to give more "dots".
Good interpolation using fractal geometry can actually do quite a
good job of inventing the "new" pixels and give quite good results
  • better than lowering printer res anyway.
If your monitor is running at 1600 X 1200 then at 100%
magnification you will see approximately 60% of the image on the
screen. However the "size" will simply depend on the screen size.

The resolution setting on EXIF (72 dpi) is just a default number
and is not affecting what you se on the screen or what your print.
In fact you can ignore it completely!!
*isteve said:
If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?
Click to expand...
No - see above - the larger the base image the higher the printer
resolution you can set and the better the image. Printers can
normally manage about 1400 dpi though this is for all three
colours, so really this is more like 500dpi. To get a 10X8" print,
just set the printer resolution in PS to 2560 (number of pixels)
divided by 10 (size of image) and you get
256 dpi - well within your printer's capability and well above the
visible threshold (where you can see the dots).
*isteve said:
So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?
Click to expand...
Absolutely not. Effectively you are using a 1.2 MP camera!!

See above. If you shot at 1280 and wanted 10" prints the printer
resolution would only be 128dpi, which is low! however if you want
to post on the Web, downsizing to this size is advisable because
the images are 1/4 the size in MB but still fill the screen!!

Hope this is understandable.

Steve
Click to expand...
 
Thanks!! :)

I think this subject confuses everyone initially, but once you figure it out the principle is simple - the unfamiliar terminology is the problem (as it so often is) and the rather pointless resolution value in EXIF which means....nothing at all!!!

Steve
caroline_d said:
Steve Jacob said:
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....
Click to expand...
Thats OK we wuz all newbies once!
caroline_d said:
Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....
Click to expand...
Economy, Standard and Fine all apply to the level of image
compression. The RAW file is about 12MB. Jpeg compression allows
"redundant" information in the file to be stripped out and
"interpolated" when the picture is recreated - so a patch of blue
sky which is all the same colour will be very compressed, whereas a
picture of a detailed subject like a tree will not. Much like
speech on a digital phone line. Higher compression makes much more
approximate decisions about what constitutes the "same" colour, so
some subtle details can be lost altogether. Lower compression has a
lower tolerance level and preserves more detail. Uncompressed files
(TIFF and RAW) make no assumptions at all and give you the lot...

Standard compression is actually pretty good - detail loss over
Fine is very slight and noise is lower. Economy mode has more
noticeable artifacts around edges and details but is probably OK
for smaller prints.

If you edit and save JPEGs repeatedly, they re-compress the image
each time - so each save loses more and more detail (what you lost
last time, plus what you lose this time). You wont see much
difference between each save, but of you do 10 saves and look at
the first and last its pretty obvious. So, any image you want to
play with in Photoshop, open the JPEG, save it as TIFF or Bitmap,
and then edit to your hearts' content.
caroline_d said:
That got me wondering whether I'm confusing resolution/size with
quality?
Click to expand...
No - they BOTH contribute to quality. Size is the MOST important
factor because it dictates the number of pixels in the final image.
Compression just dictates the degree to which these pixels are
"real" or interpolated.
caroline_d said:
2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?
Click to expand...
No - its depends entirely on the monitor or printer it is being
displayed on. There is no relationship between pixels (dots) and
size unless you take the output resolution into account.

So, set your printer resolution to 300 DPI for instance. The size
of the print will be 2560/300 inches X 1920/300 inches, or 8.5 X
6.4.

If you want larger prints (say 20") you can either
  • lower the printer resolution (fewer dots per inch --> more inches)
  • expand the image (using interpolation) to give more "dots".
Good interpolation using fractal geometry can actually do quite a
good job of inventing the "new" pixels and give quite good results
  • better than lowering printer res anyway.
If your monitor is running at 1600 X 1200 then at 100%
magnification you will see approximately 60% of the image on the
screen. However the "size" will simply depend on the screen size.

The resolution setting on EXIF (72 dpi) is just a default number
and is not affecting what you se on the screen or what your print.
In fact you can ignore it completely!!
caroline_d said:
If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?
Click to expand...
No - see above - the larger the base image the higher the printer
resolution you can set and the better the image. Printers can
normally manage about 1400 dpi though this is for all three
colours, so really this is more like 500dpi. To get a 10X8" print,
just set the printer resolution in PS to 2560 (number of pixels)
divided by 10 (size of image) and you get
256 dpi - well within your printer's capability and well above the
visible threshold (where you can see the dots).
caroline_d said:
So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?
Click to expand...
Absolutely not. Effectively you are using a 1.2 MP camera!!

See above. If you shot at 1280 and wanted 10" prints the printer
resolution would only be 128dpi, which is low! however if you want
to post on the Web, downsizing to this size is advisable because
the images are 1/4 the size in MB but still fill the screen!!

Hope this is understandable.

Steve
Click to expand...
Click to expand...
--
Steve
 
Gosh Caroline, I'm sooo hurt. I worked so hard on my detailed explanation, and got nothing.

Looks like Steve has the market cornered on digital teachings. Steve, thanks for that. I learned a thing or two myself.

Happy shooting everyone,

Freddy
 
Steve Jacob wrote:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
*isteve said:
Standard compression is actually pretty good - detail loss over
Fine is very slight and noise is lower. Economy mode has more
noticeable artifacts around edges and details but is probably OK
for smaller prints.
Click to expand...
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Steve,

This is what I've noticed in the two weeks or so with my 7i, and I'm beginning to believe that shooting in standard mode has tremendous advantages and very few, 'significant', disadvantages, notwithstanding the loss of subtle color nuances from fine to standard which you also mentioned.

I am not much of a color man in that I have difficulty sometimes (more often than that, actually) seeing subtle color differences. But that takes practice + a 'good eye' and even then I've found that several good eyes may not always agree about what they see (If you are a B&W enthusiast, would there be an equivalent but maybe less noticeable loss in tonal gradation from highlight to shadow???).

I believe that standard compression is not only pretty good, but damn good, as it takes a linen tester on an 8 x 10 print for me to see the difference in how well detail is resolved (for me, this is 'resolution') and even then, as you note, it is very slight.

My point, my question, is wouldn't shooting in standard mode take good care of a lot of complaints re: processing time, post processing time, noise(This has only recently come to my attention via the Forum and I'm not sure why it would be the case.), storage, and so on, not to mention better high speed continuous shooting for the sports buff??????????????

Gerald
 
And I appreciated the "simple formula" for printouts. - Jean
Freddy Rozentzvaig said:
Your question isn't stupid, nor confusing - even though the theme
certainly is confusing. I've been in digital for nearly 3 years,
and it has taken me nearly that long to get it figured out. So
here goes my semi amateur attempt at answering your question. I'll
do it in simple steps to help me refresh my own memory and
abilities.

Resolution = size in pixels
Quality = compression level (only for jpeg files - TIFF and RAW are
not compressed at all, but are too darn big to use in amateur
applications)

The size calculation you performed is near perfect, but
unfortunately, only applies for the SCREEN. You see, on a computer
screen, your images are displayed at 72 dots per inch. On a
printer, however, the resolution is closer to 300 dots per inch.
So if you were to recalculate your sizes using 300 instead of 72,
it almost looks like we're stuck with small print outs. That is
not so.

Here is my simple formula (and it is quite conservative):
2mp = 1600x1200 = able up to to print 5x7
3mp = 2048x1536 = able up to to print 8x10
4mp = 2240x1680 = able up to to print 11x14
5mp = 2560x1920 = whatever the next size would be.

Basically what I've said above is the following: With the different
megapixel counts, which equal to the resolutions I listed, you can
print up to those sizes without any pixelation at all. At these
sizes, these pictures will look like they were taken with film.
Above that, you begin a gradual pixelation. With that said, I can
tell you that I've printed 1600x1200 images at 8x10 with no visible
pixelation - just a little softness.

I think that's all on resolution. Compression is a simpler story.
Basically, compression is how much the camera manipulates the
original file to take it from big to small. The compression has
absolutely no bearing on the pixelation. It affects sharpness,
detail, crispness. So if you have the card space, always try to
shoot best quality = least compression.

Wow, I'm winded. I hope this helps. I must say, it was a good
refresher for me too.

Happy shooting, and feel free to ask anything you'd like. I'll
always try to help.

Freddy
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
Click to expand...
 
You are very welcome. I hopeit works for you.
Jean Ricket said:
Freddy Rozentzvaig said:
Your question isn't stupid, nor confusing - even though the theme
certainly is confusing. I've been in digital for nearly 3 years,
and it has taken me nearly that long to get it figured out. So
here goes my semi amateur attempt at answering your question. I'll
do it in simple steps to help me refresh my own memory and
abilities.

Resolution = size in pixels
Quality = compression level (only for jpeg files - TIFF and RAW are
not compressed at all, but are too darn big to use in amateur
applications)

The size calculation you performed is near perfect, but
unfortunately, only applies for the SCREEN. You see, on a computer
screen, your images are displayed at 72 dots per inch. On a
printer, however, the resolution is closer to 300 dots per inch.
So if you were to recalculate your sizes using 300 instead of 72,
it almost looks like we're stuck with small print outs. That is
not so.

Here is my simple formula (and it is quite conservative):
2mp = 1600x1200 = able up to to print 5x7
3mp = 2048x1536 = able up to to print 8x10
4mp = 2240x1680 = able up to to print 11x14
5mp = 2560x1920 = whatever the next size would be.

Basically what I've said above is the following: With the different
megapixel counts, which equal to the resolutions I listed, you can
print up to those sizes without any pixelation at all. At these
sizes, these pictures will look like they were taken with film.
Above that, you begin a gradual pixelation. With that said, I can
tell you that I've printed 1600x1200 images at 8x10 with no visible
pixelation - just a little softness.

I think that's all on resolution. Compression is a simpler story.
Basically, compression is how much the camera manipulates the
original file to take it from big to small. The compression has
absolutely no bearing on the pixelation. It affects sharpness,
detail, crispness. So if you have the card space, always try to
shoot best quality = least compression.

Wow, I'm winded. I hope this helps. I must say, it was a good
refresher for me too.

Happy shooting, and feel free to ask anything you'd like. I'll
always try to help.

Freddy
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
Click to expand...
Click to expand...
 
According to an ex-girlfriend of mine, a lot!

Sorry,

Couldn't resist.

OK I'll say someting productive.

When you take a digital picture the camera is capable of collecting a lot of information. Unfortunately, this information takes up a lot of space. You don't need all of it. The amount that you do need depends on what you plan to do with the picture. If you are going to do some post processing in photoshop (or what ever) you may want to keep all the information around. If you just want a photo and are not too picky, you can have the camera make decisions for you as to what is worth keeping and what is not.

If you want to make large prints (or any, for that matter) the more information an editing program has to work with, the better job it will do.

When you save to .jpg some information is being lost. This will result in a smaller file size but if you want to print out an 8x10 (or greater) at a later date, you may have problems.

Here is an example. I shoot medium format. I then scan in the negatives. A single image is typically 50 megs big! Do I really need all the information in that file? no. But hard disk space is cheap and by saving it all I can do anything I want with it later. That's why some people store their photos in "Raw" format. It is big and slow but you will have the most options later on.
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
 
Craig,

I agree with all the information you've given. It's right on, except that one part may mislead the neophite.

Printing an 8x10 from a jpeg, for an amateur, shouldn't cause any problems (i.e. visible loss) whatsoever. I've been shooting digital at the serious amateur level for 3 years, and have printed tons of 8x10s, both at home and at labs. They've always been fabulous, notwithstanding my sometimes horrendous composition errors, and all from jpeg files. Many even have heavy post processing like effects and color changes.

Now, I know that for a pro application, this may not be suitable, but for the serious amateur and snapshooter, jpeg should always do just fine.

Happy shooting to all,

Freddy
Craig Brown said:
Sorry,

Couldn't resist.

OK I'll say someting productive.
When you take a digital picture the camera is capable of collecting
a lot of information. Unfortunately, this information takes up a
lot of space. You don't need all of it. The amount that you do need
depends on what you plan to do with the picture. If you are going
to do some post processing in photoshop (or what ever) you may want
to keep all the information around. If you just want a photo and
are not too picky, you can have the camera make decisions for you
as to what is worth keeping and what is not.

If you want to make large prints (or any, for that matter) the more
information an editing program has to work with, the better job it
will do.

When you save to .jpg some information is being lost. This will
result in a smaller file size but if you want to print out an 8x10
(or greater) at a later date, you may have problems.

Here is an example. I shoot medium format. I then scan in the
negatives. A single image is typically 50 megs big! Do I really
need all the information in that file? no. But hard disk space is
cheap and by saving it all I can do anything I want with it later.
That's why some people store their photos in "Raw" format. It is
big and slow but you will have the most options later on.
MikeTTF said:
Remember, I'm new to digital photography ... so I'm prone to asking
an ill-advised question or two. ;-) Onward .....

Today there was some mention here concerning how size - resolution
  • compression level and sensitivity interact. Someone said that
"quality" is in the compression level ---- determined by the
"Economy" - "Standard" - "Fine" settings .....

That got me wondering whether I'm confusing resolution/size with
quality?

2560 X 1920 pixels is roughly equivalent to 35 X 26 inches. Right?

If I want an 8 X 10 inch print to result, why would I shoot a 72%
larger image at 2560, only to downsize/re-sample it?

An 8 X 10 is only 576 X 720 - yes?

So, to summarize .. With 8 X 10's in mind -- I'm shooting at "ISO
100" -- "Fine" -- "2560"

Would it be "better" to shoot "ISO 100" -- "Fine" -- "1280" ?

TIA. I hope this isn't too stupid or confusing. :-)

Mike TTF
Click to expand...
Click to expand...
 
I'm beginning to wonder!! I need to take some more tests to be sure, but I think he only real diff between fine and standard mode is some subtle colour gradation and possible edge sharpness on diagonals, but on an 8x10 I'm not sure I could see it.

Steve
Gerald Warren said:
Gerald Warren said:
Standard compression is actually pretty good - detail loss over
Fine is very slight and noise is lower. Economy mode has more
noticeable artifacts around edges and details but is probably OK
for smaller prints.
Click to expand...
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . .

Steve,

This is what I've noticed in the two weeks or so with my 7i, and
I'm beginning to believe that shooting in standard mode has
tremendous advantages and very few, 'significant', disadvantages,
notwithstanding the loss of subtle color nuances from fine to
standard which you also mentioned.

I am not much of a color man in that I have difficulty sometimes
(more often than that, actually) seeing subtle color differences.
But that takes practice + a 'good eye' and even then I've found
that several good eyes may not always agree about what they see (If
you are a B&W enthusiast, would there be an equivalent but maybe
less noticeable loss in tonal gradation from highlight to
shadow???).

I believe that standard compression is not only pretty good, but
damn good, as it takes a linen tester on an 8 x 10 print for me to
see the difference in how well detail is resolved (for me, this is
'resolution') and even then, as you note, it is very slight.

My point, my question, is wouldn't shooting in standard mode take
good care of a lot of complaints re: processing time, post
processing time, noise(This has only recently come to my attention
via the Forum and I'm not sure why it would be the case.), storage,
and so on, not to mention better high speed continuous shooting for
the sports buff??????????????

Gerald
Click to expand...
 
now Freddy...your explanation was good too. But I can't just spend ALL my time at work reading this forum and praising people, can I? I REALLY never get annthing done!
Freddy Rozentzvaig said:
Gosh Caroline, I'm sooo hurt. I worked so hard on my detailed
explanation, and got nothing.

Looks like Steve has the market cornered on digital teachings.
Steve, thanks for that. I learned a thing or two myself.

Happy shooting everyone,

Freddy
Click to expand...
 
I know exactly what you mean. Look at us, going back and forth during work hours. And here I thought everyone on the forum was a pro photographer that does weddings on the weekends, and just stays in the forum during the week.

I guess I'm not the only one with a real job hoping my real job could be digital photography, and posting and reading messages on this forum. Darn!!!

Have a good day!

Freddy
caroline_d said:
Freddy Rozentzvaig said:
Gosh Caroline, I'm sooo hurt. I worked so hard on my detailed
explanation, and got nothing.

Looks like Steve has the market cornered on digital teachings.
Steve, thanks for that. I learned a thing or two myself.

Happy shooting everyone,

Freddy
Click to expand...
Click to expand...
 
I forgot to mention that one advantage of a 5MP image is that you can print it without ANY interpolation.

When you resize the image in PS prior to printing, you can set the interpolation flag OFF and use the resolution scale to get the right size for your print. Anything > 250 will give a nice printout - 256 will give you 10X8.

On my 3MP Nikon I had to interpolate the image to get the same size prints. Freddy's table also assumes image interpolation which is why his pic sizes at 300 dpi are bigger. He's pointed out usefully just how big you can interpolate an image without noticing much pixellation. In fact if you use a fractal interpolation tool you can go slightly bigger because it works better than the simple bicubic in Photoshop.
Freddy Rozentzvaig said:
Here is my simple formula (and it is quite conservative):
2mp = 1600x1200 = able up to to print 5x7
3mp = 2048x1536 = able up to to print 8x10
4mp = 2240x1680 = able up to to print 11x14
5mp = 2560x1920 = whatever the next size would be.
Click to expand...
In this case, set the interpolation tab ON, select "bicubic" and choose the output SIZE you want in inches/cm (say 14 X 11) and the resolution you want (say 300).

Photoshop will then interpolate the orignal adding extra pixels to give you an image thats 14X300 by 11X300 pixels, or 4200 X 3300. Thats a pretty big file! However, this image has been interpolated - there is no more info in it than there was in the original, just more pixels - so DON'T SAVE IT or you will overwrite the original.

As Freddy says you can go up to a 17" print from 5MP without noticing much pixellation, but inkjets cannot handle paper larger than A3 which is about 10 X 14".
--
Steve
 
You get a good camera speed in FINE. If you use a microdrive you can still get c.500 images on it.
It prints out o.k, at up to A3.
If you shoot in STANDARD you can never recapture the pixels you've thrown away.

If storage space on your hard drive is an issue invest in a CDwriter- you won't regret it.
Failing that just be ruthless in which pictures you keep.

Wouldn't bother with RAW at this stage at all, and use TIFF only to save images in on the computer when you are working in photoshop - saving in JPEG compressses the image further with every save.
Regards,
DaveMart
 
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