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

Stephen H. Westin wrote:
"William Graham" writes:

snip

That means a 24 x 36 mm sensing plane would need about 12 megapixels to have
the same resolution as film. Digital cameras are not too far from that
now....Perhaps in another couple of years..........


Huh? The Kodak almost-14MP DCS Pro 14n shipped over a year ago. And
the DCS Pro SLR/n has replaced it, using an improved sensor.
I think he meant *affordable* cameras with that many pixels. I've
actually been thinking when that it's when we get there that I'll buy a
digital SLR. Also, *maybe* somewhere around that range the "megapixel"
race will slow down a bit, and perhaps then a new camera won't be
obsolete after about two months...

BTW. Do you know more about this sensor? It is full-frame, right? I'm
really interested in knowing if they have resolved the problems that
have lead to the use of smaller sensors so far.
It uses
Nikon-mount lenses, and there is a Canon-mount sibling, the
SLR/c. Several people are using these in lieu of medium-format film
equipment, as they feel the image quality is better.

And medium-format backs reached 16MP some years ago; the best current
single-shot backs have 22MP.
Oh, and I'm waiting for that that, too, on a 35mm-format camera (as I've
mentioned already),
or at least dreaming about it. A replaceable back, that is. Not
necessarily a system that
would allow you to switch between digital and film, but something that
would give you more flexibility in the sensor department somehow.

I was surprised how good prints from 35mm Gigabilfilm looked.
I made 20x30cm. No grains at all and super sharp even with a x15 magnifier
directly on
the print. I think more people should try this film.

Max

"Chris Loffredo" skrev i en meddelelse
...
David J. Littleboy wrote:


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.


I agree that 20x24 is stretching things a bit (no pun intended) using
35mm and that MF or LF would be far preferable, but with a good negative
the results are still acceptable, especially at real viewing distances.

I much more often do 30x40 cm (12x16) with fully satisfactory results
(given of course a decent negative). In a direct comparison with a MF
shot, there is a little less tonal smoothness & 3D look, but then I
wonder how much tonal smoothness & 3D look digital would have in this
case.

Chris

I was surprised how good prints from 35mm Gigabilfilm looked.
I made 20x30cm. No grains at all and super sharp even with a x15 magnifier
directly on
the print. I think more people should try this film.

Max

"Chris Loffredo" skrev i en meddelelse
...
David J. Littleboy wrote:


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.


I agree that 20x24 is stretching things a bit (no pun intended) using
35mm and that MF or LF would be far preferable, but with a good negative
the results are still acceptable, especially at real viewing distances.

I much more often do 30x40 cm (12x16) with fully satisfactory results
(given of course a decent negative). In a direct comparison with a MF
shot, there is a little less tonal smoothness & 3D look, but then I
wonder how much tonal smoothness & 3D look digital would have in this
case.

Chris

"Stephen H. Westin" wrote in message
...
"William Graham" writes:

snip

That means a 24 x 36 mm sensing plane would need about 12 megapixels to
have
the same resolution as film. Digital cameras are not too far from that
now....Perhaps in another couple of years..........

Huh? The Kodak almost-14MP DCS Pro 14n shipped over a year ago. And
the DCS Pro SLR/n has replaced it, using an improved sensor. It uses
Nikon-mount lenses, and there is a Canon-mount sibling, the
SLR/c. Several people are using these in lieu of medium-format film
equipment, as they feel the image quality is better.

And medium-format backs reached 16MP some years ago; the best current
single-shot backs have 22MP.

Yes.....I should have said, "Digital cameras at a reasonable price are not
too far from that now....Perhaps in another couple of years."

"Stephen H. Westin" wrote in message
...
"William Graham" writes:

snip

That means a 24 x 36 mm sensing plane would need about 12 megapixels to
have
the same resolution as film. Digital cameras are not too far from that
now....Perhaps in another couple of years..........

Huh? The Kodak almost-14MP DCS Pro 14n shipped over a year ago. And
the DCS Pro SLR/n has replaced it, using an improved sensor. It uses
Nikon-mount lenses, and there is a Canon-mount sibling, the
SLR/c. Several people are using these in lieu of medium-format film
equipment, as they feel the image quality is better.

And medium-format backs reached 16MP some years ago; the best current
single-shot backs have 22MP.

Yes.....I should have said, "Digital cameras at a reasonable price are not
too far from that now....Perhaps in another couple of years."

Toralf wrote in
:

Hi.

Hi self - now - it is obvious from your post that you
have not been hanging around here so long. This is the
favourite topic that pops up now and then. From that
perspective - your questions are more than valid.

I'm still wondering about how good the image quality of modern digital
cameras (especially SLRs) really is, in particular how it compares
with 35mm film. I've seen many articles on the subject on the Net, but
few of them seem to give you a lot of tangible information (I want to
see the numbers, please), and I can't help feeling that tests they
refer to are usually done to prove a point, i.e. that digital cameras
are as good as 35mm, which is not the way you do proper research.

Proper research? hmmm .... I don't think it is reasonable to expect
that anyone starts some kind of proper research on this topic. Film
is the old medium - digital is the new - gradually one will diminish
and the other take over. If any comparisons is biased or not does not
matter the slightest. Oh - I understand that you want to know, and I
want to know and lots of people wants to know. But proper research is
not just something done because some wants to know.

On the other hand I think you have missed that some really nice
comparisons have been made. Lots of references can be found in old
topics in this forum.

1. What is the resolution of a 35mm film anyway? I think I read
somewhere that a colour negative is at least 3000dpi. Is that
correct? How about black&white? (Yeah I know, a film doesn't have
pixels in exactly the same sense as a digital image, but it *is* made
up of discrete elements after all.)

I think it is rather safe to say that 35 mm film is at most 20 Mpixels
with regards to resolution. But ... before that you start to see grain.
If you like the grainy look, thats just perfect. If you don't, then maybe
6 Mpixels or so gives you grain free pictures from the very best 35 mm
films.

I also think it is rather safe to say that at higher ISO, film just
have to give away for DSLR cameras.

2. What about the print? 300dpi?

Hmm ... yes what about it?

It all depends on the viewing distance and your demands.

3. I know that the most common sensors are made up of individual
elements for the read, green and blue channels, arranged in a special
pattern, whose data is somehow interpolated into RGB pixels. But what
exactly does e.g. 6 megapixels mean in that context? Does it mean that
the sensor has (just) 6 million elements, or that data from a higher
number (like 18 or 24 million) is combined into 6 million RGB pixels?

A 6 Mpixel camera (using Bayer mosaic filter) has 6 Million sensels,
3 Million green, 1.5 Million red and 1.5 Million blue. Advanced
algorithms makes a picture with a resolution of (nearly) 6 Mpixels.
The color resolution is lower though - just as for your TV. And the
same kind of problems exist if you have equal luminosity color patterns.
Fortunately, your eye cannot resolve such patterns either.

The same question more bluntly put: When Canon/Nikon/Pentax is talking
about 6MP, is that just a big a lie as the one about 10MP on Sigma
cameras? (I'm hoping not, as I think the Sigma/Foveon way of counting
really takes the cake.)

The Sigma counting is a lie IMHO. Most here agree - some don't. Lots
of fun here to read in old posts

The Canon/Nikon/Pentax/all_other_except_sigma Bayer sensor counting
is not a lie IMHO. Or at least it is a white lie. A Bayer sensor with
6 Milion sensors is capable of resolving 6 Mpixel (except for strangly
colored patterns that the eye cannot resolve either).

4. Can the inaccuracy associated with the above mentioned
interpolation be quantified and/or measured against e.g. the error
introduced by scanning a negative with a film-scanner? And how does it
compare with pixel interpolation in the scanning sense?

No comparison possible IMHO. The Bayer computation is not equal
to interpolation. Interpolation is only used to extract color
information. The direct values are used for luminosity - no
interpolation is made for luminosity.

5. And how about those other parameters I mentioned briefly above -
like different kinds of geometric distortions, noise, flat field bias
etc.? Can those be compared with the ones of plain old film?

Yes - but are those not lens properties?

6. And the chromic aberration effects? How serious are they these
days? And are the full-frame sensors that are actually found in some
high-end cameras now, in any way comparable to film in that respect?

Same here - those are lens properties.

Well, maybe some people will say I have a somewhat critical or
conservative attitude towards digital cameras, but I actually think
you ought to be a bit sceptical when something "new and wonderful"
comes a long; new technology is too often introduced for technology's
own sake, IMO.

Ahhh ... you missed that also Digital is not something new and
wonderful. It has been here for a while. And - it is rather wonderful.
It has improved life for photographers (IMHO) a lot.



/Roland

"David J Taylor"
wrote in :

Stephen H. Westin wrote:
"BeamGuy" writes:

Well, at 40 cycles per degree, and perhaps a 140-degree horizontal
field of view, it's over 10,000 pixels across. We don't have any
display that can approach it.

No, you don't get resolution across the full FOV, just in the central
area....


Ah --- but you mentally integrate over maybe 70 degrees by scanning.
So - 5,000x2,000 pixel - thats 10 Mpixels. As a rough estimate, thats
very near to DSLRs.


/Roland

"Zebedee" wrote in news:410107b0$0$2478$afc38c87
@news.ukonline.co.uk:

I wasn't talking about printer dpi. I was talking about image dpi...


To avoid confusion, call it ppi.


/Roland

"Zebedee" wrote in news:410107b0$0$2478$afc38c87
@news.ukonline.co.uk:

I wasn't talking about printer dpi. I was talking about image dpi...


To avoid confusion, call it ppi.


/Roland

"scott" wrote:
"Zebedee" wrote in message

Just why would anybody print at more than 150dpi when that's the
maximum the eye can see?

Rubbish! It depends how closely you look at the image. My phone has
180dpi
display, and it is pretty easy to see the individual pixels. A 250dpi
display looks *much* smoother. I guess the same goes for prints.

Exactly.

At A4, 1Ds images (320 dpi or so) look a lot better than 6MP images (240
dpi). A lot. The 1Ds is getting close to what I consider "photographic
quality" at A4, neither 6MP nor 35mm are even in the ballpark.

(To repeat my standard rant: we've set the bar too low by looking at that
inferior subminiature format known as 35mm.)

David J. Littleboy
Tokyo, Japan