8Mp Digital The Theoretical 35mm Quality Equivelant

"Petros" wrote in message
...
Skip M posted:
"Petros" wrote in message
...
Harvey posted:

"Petros" wrote in message
...
Skip M posted:
"Crownfield" wrote in message
...
Harvey wrote:

"Donald Brummel" wrote in message
ink.net...
Sigh, if they "easily beat film" what is point of the newer
4800
dpi
film/slide
scanners?

A 2700 DPI (ie, Nikon Coolscan III) scanner gets you about 28
Meg
per
negative/slide. That is only good for an 8x10. Barely, really
just a
nice
5x7.

28Meg? By my calculations a 2700DPI from a 35mm slide etc. would
give
something like 3500 x 2500 (give or take), which is about
8.5MPix

you and i think in terms of pixel dimensions, like 3000 x 2000.

some people think image quality is measured by file size.

In that case, the 20D is competitive by Mr. Brummel's standards,
it
produces a 24 meg JPEG file...


impossible.

Why would it be impossible?
For a 24 MB Jpeg (assuming best quality, lowest compression) you would
need a 250 MB tif source file. Not even the 20D is capable of that. It
would be about 12,000 x 8,000 pixels, or 96 megapixels.
--
Petros
Ap' ola prin ipirche o Logos

Sorry, bud, you're wrong. The native file from my 20D, Jpeg Large/Fine
is
23.4M. It produces a RAW file that when converted to Tiff 16 bit that is
46.8M. I'd threaten to send it you, but it's too large for my server.
;-)


From http://www.digitalreview.ca/cams/CanonEOS20D.shtml
(Canon USA seems to be down, and Canon UK does not give file size info)

File sizes:

(1) Large/Fine: Approx. 3.6MB (3504 x 2336 pixels)
(2) Large/Normal: Approx. 1.8MB (3504 x 2336 pixels)
(3) Medium/Fine: Approx. 2.2MB (2544 x 1696 pixels)
(4) Medium/Normal: Approx. 1.1MB (2544 x 1696 pixels)
(5) Small/Fine: Approx. 1.2MB (1728 x 1152 pixels)
(6) Small/Normal: Approx. 0.6MB (1728 x 1152 pixels)
(7) RAW: Approx. 8.7MB (3504 x 2336 pixels)
* Exact file sizes depend on the subject, ISO speed, processing
parameters, etc.

Actually, you're the one who's wrong An uncompressed 24 bit TIF file
@ 3504x2336 px will be 23.42 MegaBytes, which on average will give
about the 3.6 MegaByte JPEG with EXIF info mentioned at the top of this
list. If you convert your RAW file to 48 bit TIF then you can have a
large file, but one that you can't do much with on a commercial printer
or imager. A 48 bit TIF is really only good at the editing stage since
you can do more color manipulation with less damage. When you go to
print or to create a JPG file, you need to convert to 24 bit. (unless
you're printing to your desktop printer, in which case your image app
is converting it for you)

So

1)Your 8 MegaPixel camera is not outputting a 23.4 MegaByte JPG file
because it's technically impossible from that camera,

2)The RAW file from your camera is not a JPG or TIF, but a lossless
compressed 48 bit file that can be converted to a 46.8 MegaByte 48 bit
uncompressed TIF or a 23.4 MegaByte 24 bit TIF,

3)You do not have a 96 MegaPixel camera

--
Petros
Ap' ola prin ipirche o Logos

I am not wrong, I went to the camera and looked at the file sizes. The
sizes I stated were the ones on the camera. That would be the equivalent of
the files from a scanner. What are the files sizes in Pshop "file size"
then? That's where I got my numbers.

--
Skip Middleton
http://www.shadowcatcherimagery.com

Skip M posted:
snipped for size
I am not wrong, I went to the camera and looked at the file sizes. The
sizes I stated were the ones on the camera. That would be the equivalent of
the files from a scanner. What are the files sizes in Pshop "file size"
then? That's where I got my numbers.

According to the table that I posted, your camera creates RAW files
(compressed) with an average of 8.7 MB and JPG files (large/fine) with
an average of 3.6 MB. These are the average sizes of the files that you
download from your camera to the hard disk. If you open that large/fine
JPG in PS it becomes uncompressed, and will show a file size of 23.42
MB and an uncompressed TIF created from that JPG will also be 23.42 MB.
The RAW file, when saved from PS as a 24 bit TIF for printing (either
to an imager or for offset*) will also be 23.42 MB. That is simply how
the image size translates into a 24 bit RGB image. You originally
stated that the camera is producing a 23 MB JPG file, which is untrue
and can be checked by right clicking on the JPG file itself and
checking properties. Photoshop is showing you the 24 bit uncompressed
file size, in case you decide to save as uncompressed TIF or PSD.

* Before someone jumps on me for stating that RGB files get used for
offset, I know that they need to be converted to CMYK first. What I'm
referring to is that it would be uncommon in many parts of the world to
convert 48 bit RGB to 64 bit CMYK, since many older imagesetters can't
deal with it yet.
--
Petros
Ap' ola prin ipirche o Logos

Skip M posted:
snipped for size
I am not wrong, I went to the camera and looked at the file sizes. The
sizes I stated were the ones on the camera. That would be the equivalent of
the files from a scanner. What are the files sizes in Pshop "file size"
then? That's where I got my numbers.

According to the table that I posted, your camera creates RAW files
(compressed) with an average of 8.7 MB and JPG files (large/fine) with
an average of 3.6 MB. These are the average sizes of the files that you
download from your camera to the hard disk. If you open that large/fine
JPG in PS it becomes uncompressed, and will show a file size of 23.42
MB and an uncompressed TIF created from that JPG will also be 23.42 MB.
The RAW file, when saved from PS as a 24 bit TIF for printing (either
to an imager or for offset*) will also be 23.42 MB. That is simply how
the image size translates into a 24 bit RGB image. You originally
stated that the camera is producing a 23 MB JPG file, which is untrue
and can be checked by right clicking on the JPG file itself and
checking properties. Photoshop is showing you the 24 bit uncompressed
file size, in case you decide to save as uncompressed TIF or PSD.

* Before someone jumps on me for stating that RGB files get used for
offset, I know that they need to be converted to CMYK first. What I'm
referring to is that it would be uncommon in many parts of the world to
convert 48 bit RGB to 64 bit CMYK, since many older imagesetters can't
deal with it yet.
--
Petros
Ap' ola prin ipirche o Logos

"Mike Kohary" writes:

Stephen H. Westin wrote:
Lourens Smak writes:

In article , "Mike Kohary"
wrote:

Huh? 35mm is a size - 35mm is 35mm. 6MP is considered
approximately equivalent, so 8MP probably exceeds 35mm in terms of
resolution.

Well, the actual resolution would depend a LOT on the lens used, for
example. (with both images). 35mm = 6MP is very simplistic.

Yes. In fact, it's a foolish thing to say.

It's not. It's a subjective evaluation, and is widely agreed upon. Unless
you have some brilliant method of direct comparison that no one else on the
planet has thought of to this point, I'd suggest you keep your rudeness to
yourself.

Then how about "For many purposes, 6MP digital appears to offer
quality competitive with 35mm?"

The images aren't the same, nor should they be. Each has its
advantages and disadvantages. Just saying the two are equivalent is so
simplistic as to be ridiculous.

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.

"Mike Kohary" writes:

Stephen H. Westin wrote:
Lourens Smak writes:

In article , "Mike Kohary"
wrote:

Huh? 35mm is a size - 35mm is 35mm. 6MP is considered
approximately equivalent, so 8MP probably exceeds 35mm in terms of
resolution.

Well, the actual resolution would depend a LOT on the lens used, for
example. (with both images). 35mm = 6MP is very simplistic.

Yes. In fact, it's a foolish thing to say.

It's not. It's a subjective evaluation, and is widely agreed upon. Unless
you have some brilliant method of direct comparison that no one else on the
planet has thought of to this point, I'd suggest you keep your rudeness to
yourself.

Then how about "For many purposes, 6MP digital appears to offer
quality competitive with 35mm?"

The images aren't the same, nor should they be. Each has its
advantages and disadvantages. Just saying the two are equivalent is so
simplistic as to be ridiculous.

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.

"Mike Kohary" writes:

Stephen H. Westin wrote:
Lourens Smak writes:

In article , "Mike Kohary"
wrote:

Huh? 35mm is a size - 35mm is 35mm. 6MP is considered
approximately equivalent, so 8MP probably exceeds 35mm in terms of
resolution.

Well, the actual resolution would depend a LOT on the lens used, for
example. (with both images). 35mm = 6MP is very simplistic.

Yes. In fact, it's a foolish thing to say.

It's not. It's a subjective evaluation, and is widely agreed upon. Unless
you have some brilliant method of direct comparison that no one else on the
planet has thought of to this point, I'd suggest you keep your rudeness to
yourself.

Then how about "For many purposes, 6MP digital appears to offer
quality competitive with 35mm?"

The images aren't the same, nor should they be. Each has its
advantages and disadvantages. Just saying the two are equivalent is so
simplistic as to be ridiculous.

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.

"John Miller" wrote in message
...

Here's a question from another angle (and if it's been thrashed out
before, my apologies): Given a full-frame (24mm x 36mm) sensor, how many
Mpx are required to take full advantage of today's best lenses?

You may be confusing theoretical limits with real-world results. One
important question is how much do you intend to enlarge your prints. If you
never go beyond, say, 8x10 are you really concerned about having enough
megapixels to enlarge to 20x30?

If all you make are 4x6 prints, than a 2.3 MP camera that shoots at
1200x1800 resolution will make an excellent quality print. The math implies
that an 8 MP camera should produce the same resolution for an 8 x10.

I use my 35mm or MF gear for y more artistic work, but I have been finding
that my wimpy 2.3MP digicam has been quite useful when taking images that
are not meant to be enlarged very much. I can carry it with me anywhere,
with no need to lug multiple lenses, filters, film canisters and other such
junk. I have better control over the final image because I can do my own
post-shoot tweaking.

Most important to me, I take more photos, because I am not reluctant to
carry a full 35mm kit wherever I go. And, to my way of thinking, any image
is better than no image at all.

For 4x6 prints, I do better with my digicam than I would with my 35mm and
one-hour processing. One of these days I might upgrade to something better,
but my current needs are met just fine by using the digicam for the more
mundane types of shots and hauling out the 35mm or MF for the more demanding
situations. The 80/20 rule applies: 80% of my mundane shots are ok with
the digicam and the 20% that are more critical can be well served with the
film gear.

No one camera can do everything. I have stopped searching for the one
digital camera that can completely replace my film cameras. One can go nuts
by searching for the Holy Grail of camera perfection.

"John Miller" wrote in message
...

Here's a question from another angle (and if it's been thrashed out
before, my apologies): Given a full-frame (24mm x 36mm) sensor, how many
Mpx are required to take full advantage of today's best lenses?

You may be confusing theoretical limits with real-world results. One
important question is how much do you intend to enlarge your prints. If you
never go beyond, say, 8x10 are you really concerned about having enough
megapixels to enlarge to 20x30?

If all you make are 4x6 prints, than a 2.3 MP camera that shoots at
1200x1800 resolution will make an excellent quality print. The math implies
that an 8 MP camera should produce the same resolution for an 8 x10.

I use my 35mm or MF gear for y more artistic work, but I have been finding
that my wimpy 2.3MP digicam has been quite useful when taking images that
are not meant to be enlarged very much. I can carry it with me anywhere,
with no need to lug multiple lenses, filters, film canisters and other such
junk. I have better control over the final image because I can do my own
post-shoot tweaking.

Most important to me, I take more photos, because I am not reluctant to
carry a full 35mm kit wherever I go. And, to my way of thinking, any image
is better than no image at all.

For 4x6 prints, I do better with my digicam than I would with my 35mm and
one-hour processing. One of these days I might upgrade to something better,
but my current needs are met just fine by using the digicam for the more
mundane types of shots and hauling out the 35mm or MF for the more demanding
situations. The 80/20 rule applies: 80% of my mundane shots are ok with
the digicam and the 20% that are more critical can be well served with the
film gear.

No one camera can do everything. I have stopped searching for the one
digital camera that can completely replace my film cameras. One can go nuts
by searching for the Holy Grail of camera perfection.

"John Miller" wrote in message
...

Here's a question from another angle (and if it's been thrashed out
before, my apologies): Given a full-frame (24mm x 36mm) sensor, how many
Mpx are required to take full advantage of today's best lenses?

You may be confusing theoretical limits with real-world results. One
important question is how much do you intend to enlarge your prints. If you
never go beyond, say, 8x10 are you really concerned about having enough
megapixels to enlarge to 20x30?

If all you make are 4x6 prints, than a 2.3 MP camera that shoots at
1200x1800 resolution will make an excellent quality print. The math implies
that an 8 MP camera should produce the same resolution for an 8 x10.

I use my 35mm or MF gear for y more artistic work, but I have been finding
that my wimpy 2.3MP digicam has been quite useful when taking images that
are not meant to be enlarged very much. I can carry it with me anywhere,
with no need to lug multiple lenses, filters, film canisters and other such
junk. I have better control over the final image because I can do my own
post-shoot tweaking.

Most important to me, I take more photos, because I am not reluctant to
carry a full 35mm kit wherever I go. And, to my way of thinking, any image
is better than no image at all.

For 4x6 prints, I do better with my digicam than I would with my 35mm and
one-hour processing. One of these days I might upgrade to something better,
but my current needs are met just fine by using the digicam for the more
mundane types of shots and hauling out the 35mm or MF for the more demanding
situations. The 80/20 rule applies: 80% of my mundane shots are ok with
the digicam and the 20% that are more critical can be well served with the
film gear.

No one camera can do everything. I have stopped searching for the one
digital camera that can completely replace my film cameras. One can go nuts
by searching for the Holy Grail of camera perfection.

Jeremy wrote:
"John Miller" wrote in message
...
Here's a question from another angle (and if it's been thrashed out
before, my apologies): Given a full-frame (24mm x 36mm) sensor, how many
Mpx are required to take full advantage of today's best lenses?

You may be confusing theoretical limits with real-world results. One
important question is how much do you intend to enlarge your prints. If you
never go beyond, say, 8x10 are you really concerned about having enough
megapixels to enlarge to 20x30?

Thanks for the reply, but no, I meant exactly what I asked. Let me try
it another way: given today's top-performing 35mm lenses as the
objectives, how many megapixels are needed (in a 24mm x 36mm sensor)
before addition Mpx provide no added benefit?

If you never go beyond, say, 8x10 are you really concerned about
having enough megapixels to enlarge to 20x30?

Of course. Enlargement size is only relevent in the context of viewing
distance. If you've ever shot for a billboard, you know what I mean.

--
John Miller, who began shooting 35mm professionally in 1960, against
general derision from the 4x5 crowd

email address: domain, n4vu.com; username, jsm
Surplus (FSoT):
Nikon n80 body