Digital quality (vs 35mm): Any real answers?

"Zebedee" wrote:
"Chris Loffredo" wrote:
Zebedee wrote:

I have 50x60 (cm) B&W photo paper which I use for the right pictures.
I doubt 3 (or 6) megapixels will do the job...

50cm = 19.7 inches
60cm = 23.6 inches

19.7 x 150 = 2955 pixels
23.6 x 150 = 3540 pixels

2955 x 3540 = 10.4607 megapixels

It could be a little stretch for a 6mp camera or you could even use the
Kodak 14mp SLR

Having said that, it's a really unusual size and more suited to medium
format than for 35mm.

20x24 is a pitiful joke from 35mm B&W films, even Tech Pan. If one has any
sense of quality imaging at all, 11x14 is MF (645) territory. 20x24 from 6x7
would be OK, but would look better if you used LF.

David J. Littleboy
Tokyo, Japan

"Zebedee" wrote:
"Chris Loffredo" wrote:
Zebedee wrote:

I have 50x60 (cm) B&W photo paper which I use for the right pictures.
I doubt 3 (or 6) megapixels will do the job...

50cm = 19.7 inches
60cm = 23.6 inches

19.7 x 150 = 2955 pixels
23.6 x 150 = 3540 pixels

2955 x 3540 = 10.4607 megapixels

It could be a little stretch for a 6mp camera or you could even use the
Kodak 14mp SLR

Having said that, it's a really unusual size and more suited to medium
format than for 35mm.

20x24 is a pitiful joke from 35mm B&W films, even Tech Pan. If one has any
sense of quality imaging at all, 11x14 is MF (645) territory. 20x24 from 6x7
would be OK, but would look better if you used LF.

David J. Littleboy
Tokyo, Japan

"Zebedee" wrote in message
...
I spent ages working out all the details. I came to the conclusion that if
you measured the area of a perfect print from a 35mm negative or 35mm
slide
in inches and then divided the dimensions by 150 you'd be able to work out
the vertical/horizontal pixels of the image. Then simply multiply the two
together to get megapixels. That's the theory anyway.

In practice, how big is the biggest print you normally make? If your
normal
biggest print is 10x8 then 3 megapixels is all you ever need (two at a
pinch).

But the biggest limitation is your printer. How many of us can afford an
A3
or greater printer or even the ink to make A3 prints?

How many A4 prints can you hang on your wall?

I decided to settle on 3 megapixels. It's adequate for my needs and as
with
slides, I ensure my photos are perfect before I squeeze the button. I
claim
3 megapixels is the perfect equivalent of 35mm for most purposes. 6mp just
eats up storage space for no visible advantage.

--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)



You may claim it, but that don't make it so. There is a decided difference
between files from my Canon D30 (3mp) and my wife's 10D (6mp) cameras. 3mp
is most definitely not the equivalent of film for anyone who is enlarging
beyond 4x6.
I have a Canon 9000 printer that prints photo quality A3+ prints, we both
regularly print to that size and A4, we have about 20 16x20 inch frames
hanging on the wall in our stairwell, alone, as we speak. I have a show
coming up in which more than half the images need to be printed A3+. Your
theory won't work for me, and I'll bet that in a short time, you'll realize
that you are dissatisfied with the images you are getting utilizing that
theory, too.

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

"Zebedee" wrote in message
...
I spent ages working out all the details. I came to the conclusion that if
you measured the area of a perfect print from a 35mm negative or 35mm
slide
in inches and then divided the dimensions by 150 you'd be able to work out
the vertical/horizontal pixels of the image. Then simply multiply the two
together to get megapixels. That's the theory anyway.

In practice, how big is the biggest print you normally make? If your
normal
biggest print is 10x8 then 3 megapixels is all you ever need (two at a
pinch).

But the biggest limitation is your printer. How many of us can afford an
A3
or greater printer or even the ink to make A3 prints?

How many A4 prints can you hang on your wall?

I decided to settle on 3 megapixels. It's adequate for my needs and as
with
slides, I ensure my photos are perfect before I squeeze the button. I
claim
3 megapixels is the perfect equivalent of 35mm for most purposes. 6mp just
eats up storage space for no visible advantage.

--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)



You may claim it, but that don't make it so. There is a decided difference
between files from my Canon D30 (3mp) and my wife's 10D (6mp) cameras. 3mp
is most definitely not the equivalent of film for anyone who is enlarging
beyond 4x6.
I have a Canon 9000 printer that prints photo quality A3+ prints, we both
regularly print to that size and A4, we have about 20 16x20 inch frames
hanging on the wall in our stairwell, alone, as we speak. I have a show
coming up in which more than half the images need to be printed A3+. Your
theory won't work for me, and I'll bet that in a short time, you'll realize
that you are dissatisfied with the images you are getting utilizing that
theory, too.

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

Gordon Moat writes:

[an *extremely* detailed and clear discussion of many of the issues in
the topi in the subject line]

First, *very* nice explanation! It obviously involved quite a bit of
work.

Second, I think one very important point often missed in this
discussion is that digital and film images enlarge entirely
*differently*.

Even a first-rate slow film image acquires grain (clumps) as it's
enlarged enough. A digital image *doesn't*. It gradually gets
softer, but there is no underlying grain structure to appear (the
underlying pixel structure doesn't appear because the decent
interpolation algorithms prevent it).

An experienced film photographer looking for flaws in a big print from
digital may be looking for the wrong thing; one of the things I look
for is how the grain is doing, and in a print from a digital original,
I'm not going to find any.

This difference in how they enlarge probably accounts for part of the
wide range of discussion about what "equivalent" resolutions are.
Some people mind grain more than others, some people's eyes are
probably more attuned to noticing some kinds of softness or missing
details than others, so they'll have different tolerances for various
size prints from film and digital originals.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

Gordon Moat writes:

[an *extremely* detailed and clear discussion of many of the issues in
the topi in the subject line]

First, *very* nice explanation! It obviously involved quite a bit of
work.

Second, I think one very important point often missed in this
discussion is that digital and film images enlarge entirely
*differently*.

Even a first-rate slow film image acquires grain (clumps) as it's
enlarged enough. A digital image *doesn't*. It gradually gets
softer, but there is no underlying grain structure to appear (the
underlying pixel structure doesn't appear because the decent
interpolation algorithms prevent it).

An experienced film photographer looking for flaws in a big print from
digital may be looking for the wrong thing; one of the things I look
for is how the grain is doing, and in a print from a digital original,
I'm not going to find any.

This difference in how they enlarge probably accounts for part of the
wide range of discussion about what "equivalent" resolutions are.
Some people mind grain more than others, some people's eyes are
probably more attuned to noticing some kinds of softness or missing
details than others, so they'll have different tolerances for various
size prints from film and digital originals.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

"Zebedee" writes:

"Chris Loffredo" wrote in message
...
Zebedee wrote:
I have 50x60 (cm) B&W photo paper which I use for the right pictures.
I doubt 3 (or 6) megapixels will do the job...

50cm = 19.7 inches
60cm = 23.6 inches

19.7 x 150 = 2955 pixels
23.6 x 150 = 3540 pixels

2955 x 3540 = 10.4607 megapixels

It could be a little stretch for a 6mp camera or you could even use the
Kodak 14mp SLR

Having said that, it's a really unusual size and more suited to medium
format than for 35mm.

I have, over the years, been more unhappy than not in printing 35mm up
to a size slightly smaller than that -- 16x20.

I have a 16x24 print (slightly smaller than the example under
discussion) from a 6mp shot from my Fuji S2 that looks better than the
16x20 prints I've had made from film. But I haven't worked very hard
on making first-rate 16x20 prints from 35mm; I gave up fairly early.
Which also means I haven't tried it with modern films. Still, the
16x24 inkjet print looks *great*.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

"Zebedee" writes:

"Chris Loffredo" wrote in message
...
Zebedee wrote:
I have 50x60 (cm) B&W photo paper which I use for the right pictures.
I doubt 3 (or 6) megapixels will do the job...

50cm = 19.7 inches
60cm = 23.6 inches

19.7 x 150 = 2955 pixels
23.6 x 150 = 3540 pixels

2955 x 3540 = 10.4607 megapixels

It could be a little stretch for a 6mp camera or you could even use the
Kodak 14mp SLR

Having said that, it's a really unusual size and more suited to medium
format than for 35mm.

I have, over the years, been more unhappy than not in printing 35mm up
to a size slightly smaller than that -- 16x20.

I have a 16x24 print (slightly smaller than the example under
discussion) from a 6mp shot from my Fuji S2 that looks better than the
16x20 prints I've had made from film. But I haven't worked very hard
on making first-rate 16x20 prints from 35mm; I gave up fairly early.
Which also means I haven't tried it with modern films. Still, the
16x24 inkjet print looks *great*.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

nitzsche wrote:
OK, I'll take a shot at it...

It used to be "Film is cheap,' now it's "Cameras are cheap."

1. What is the resolution of a 35mm film anyway?
- For practical purposes, it's infinite.

2. What about the print? 300dpi
- Unless you're printing posters, it's not relevant.
But I want to *know* exactly how large prints you can make at "standard"
resolution with the different formats.


3. exactly does e.g. 6 megapixels mean
- 6.3 megapixels is 6,291,456 sensors.
So, it's *really* equivalent to about 2M of true RGB data???

4. Can the inaccuracy associated with the above mentioned
interpolation be measured
- Film will almost always be better, but it's what the outside eyes see
that matters.

5. geometric distortions, noise, flat field bias etc.
- That's a lens issues, not sensor/film issues
There are lens issues, but those are not the ones I'm talking about.
CCDs at least do have the problem that the light sensitivity of each
pixel or sensor is not quite the same. And there may be varying offsets,
too, i.e. each pixel doesn't quite have the same opinion on what "black"
is. Also, the individual sensors aren't necessarily evenly distributed
or positioned exactly right. Then there is the "smear" between adjacent
pixels, which is one of the arguments against CCD and for CMOS, I think.


6. And the chromic aberration effects?
- As far as I know, all digicams are prone to purple fringing, which is
something you don't see on any cheap slr.

My two cents worth.

nitzsche wrote:
OK, I'll take a shot at it...

It used to be "Film is cheap,' now it's "Cameras are cheap."

1. What is the resolution of a 35mm film anyway?
- For practical purposes, it's infinite.

2. What about the print? 300dpi
- Unless you're printing posters, it's not relevant.
But I want to *know* exactly how large prints you can make at "standard"
resolution with the different formats.


3. exactly does e.g. 6 megapixels mean
- 6.3 megapixels is 6,291,456 sensors.
So, it's *really* equivalent to about 2M of true RGB data???

4. Can the inaccuracy associated with the above mentioned
interpolation be measured
- Film will almost always be better, but it's what the outside eyes see
that matters.

5. geometric distortions, noise, flat field bias etc.
- That's a lens issues, not sensor/film issues
There are lens issues, but those are not the ones I'm talking about.
CCDs at least do have the problem that the light sensitivity of each
pixel or sensor is not quite the same. And there may be varying offsets,
too, i.e. each pixel doesn't quite have the same opinion on what "black"
is. Also, the individual sensors aren't necessarily evenly distributed
or positioned exactly right. Then there is the "smear" between adjacent
pixels, which is one of the arguments against CCD and for CMOS, I think.


6. And the chromic aberration effects?
- As far as I know, all digicams are prone to purple fringing, which is
something you don't see on any cheap slr.

My two cents worth.