digital vs. medium format

I was looking at picking up a used MF camera in my area ( ~ $500 ) and
[...]

A quality print requires 300dpi of information, which means that every
step of the final printing process must have at least that much
information. (But see my caveat below. Also, 200dpi doesn't look bad
either, but not nearly as good as 300dpi). For a 24"x36" print, then,
you need

7200x10800 or 77Mpix

for a great print, or

24x36x4000 or 34Mpix

for a good print.

Even most 35mm film has trouble coming up with 77Mpix of image data,
but medium format does very well.

[...] I asked the sales guy about the quality of the lenses, and he
said they were worse on the MF, because poor quality lenses wouldn't
be as noticeable on MF! Is this true? If so, it seems I should just

It is technically true that a minor defect on a MF lens will be less
of a problem than a minor defect on a 35mm or dSLR lens, because the
defect contributes to less of the picture on MF than on smaller
formats. But don't be misled. A good MF setup can produce much
crisper enlargements than anything a 35mm camera can.

Caveat: When I say that a good print requires 300dpi of information,
I'm talking about a good, sharp, print. I have 12x18 enlargements
from my 3Mpix camera which I love, but with only about 120dpi, they
more resemble impressionist paintings than photographs.

-Joel

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"rafeb" wrote in message
om...

Math aside,

It is also called optical bench racing - you know, where the posit is made
from the keyboard without Real Life experience.

[...] and not speaking from personal
experience, but I'm willing to wager that
a 22 Mpixel image from one of those digital
MF camera backs gets very close to matching
the best one can do in practice, with real MF
film.

Agreed on both counts. It's worth a gentlemen's bet to do such a comparison.
I bet that the outcome will show that the 22Mpx digital original will win in
all the the cases where film artifacts are not endearing. Heck, 90% of the
population can't make a decent negative/transparency scan to save their
lives. (I'm one of them!) Straight 22mpx digital to a digital print is more
likely to obviate screwups. Big Digital wins for being cleaner, more
straightforward.

"RolandRB" wrote in
oups.com:

Here's a little calculation for you to look at. Let us say you got a
6x4.5 format MF camera. And let us say the lens for it was indeed
poorer such that you could only get a maximum resolution of 45 lp/mm on
film so assume its maximum theoretical resolution was double that at 90
lp/mm so that the film sensors must be able to pick up 180 patches per
light per mm (since a line must have dark and light elements to be a
line). So a 6x4.5 (really 57mmx42mm) will have this many effective film
sensors:

57*180*42*180 = 77,565,600 sensors

Now for digital cameras, the current design is to have colored masks
over the sensors so one picks up green, one red and the other blue
light so it takes 3 digital sensors to give a true color so a digital
camera back would need:

77,565,600 * 3 = 232,696,800 pixels

So when 232 megapixels backs for MF cameras are firstly made and come
down in price to a sensible level then you can buy one to stick on the
back, knowing it will give you just as good results as film.

Nope.

The film is grainy and has a non linear response.
It is also not as flat as a digital sensor. The
color fidelity of the layers is also questionable.
There is also the matter of scanning or making
an enlargemant of the image - losing lots of quality.

Direct light to digital sensor is a much cleaner way
of recording images. Film sux!


/Roland

In article .com,
RolandRB wrote:

77,565,600 * 3 = 232,696,800 pixels

So when 232 megapixels backs for MF cameras are firstly made and come
down in price to a sensible level then you can buy one to stick on the
back, knowing it will give you just as good results as film.

I'd say that your arithmetic is being massively over-generous to the film.
IME, from shooting DSLRs and medium format and 35mm slides, you should
expect to get equivalent quality per pixel to digital at up to 1 megapixel
per square centimetre for slide film, so 36 megapixels for 6*6. If you go to
heroic lengths and use the best and most expensive equipment, you might be
able to approach double that, but 230 megapixels is out by an order of
magnitude. It juse doesn't match the real world results that people are
getting.

My 1 megapixel/cm squared gives about 8 megapixels for 35mm, btw, which is
pretty much the commonly accepted figure for where slow slide film and DSLRs
at 100ISO reach parity for overall image quality.

In article ,
Roland Karlsson wrote:

Direct light to digital sensor is a much cleaner way
of recording images. Film sux!


/Roland

No you do. IMOP.

"jjs" john@xstafford.net writes:

"Michael Benveniste" wrote in message
...

Depending on your wants, needs, shooting habits, computer skills, lab
access, etc. either one could be right for you. Before jumping into
medium format on the basis of cheap used equipment, though, remember
that consumables costs for medium format are still significant. Since
I don't develop my own film, each medium format slide costs me about
70 cents just to proof.

The hidden demon of digital at this time is the issue of replacing and
upgrading cameras (or backs) to remain in the 60% sector. The $1,500 digicam
you buy today will be worth zip in four years, but you will probably want to
replace it in three years. If you want to be at the top of the professional
game, it's far, far more expensive.

Not really. If you want to be at the top of the professional game,
you're spending 5-figure amounts in lab fees for processing and
scanning each year. You get that free with your digital body. Film
plus professional processing plus lab scanning (needed for nearly any
professional use of images these days) comes to more than $20/roll, so
a $1500 body is paid off in only 75 rolls -- far less than a single
year of professional use.

Low volume amateurs, and artists who are living off their day jobs,
are the ones really being squeezed by the current pricing structure.

I'd like to know the real sales figures on the super-high-end MF
digital backs. I strongly suspect the prices are going to remain
very high because they aren't selling enough, to make the economy of
scale; the marketplace isn't going for the product. We will know
when/if a manufacturer finally gives up on the product because they
cannot make decent-enough money for the stockholders. Stockholders
have a way of killing good things that are not highly
profitable. There's a bust coming up in two years - that's my little
risky prediction.

I suspect you're right that the prices won't come down rapidly. The
fabrications of such huge devices remains expensive, and isn't
mainstream in the fab business either so it won't benefit as much from
R&D as other types of work.

But I don't think they're 'failing' in the marketplace; I think the
professionals are using them. They're just too expensive for the
amateur market, unlike DSLRs.
--
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/

"jjs" john@xstafford.net writes:

"RolandRB" wrote in message
oups.com...
Here's a little calculation for you to look at. Let us say you got a
6x4.5 format MF camera. [...]

Here's my assertion - pure digital capture is cleaner and capable of
higher resolution color fidelity than scanned film of the same size
as the sensor. Have fun with that.

I think that's clearly true in the current state of the arts (both
film and sensors change, after all). And I love it.
--
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/

(Dr. Joel M. Hoffman) writes:

I was looking at picking up a used MF camera in my area ( ~ $500 ) and
[...]

A quality print requires 300dpi of information, which means that every
step of the final printing process must have at least that much
information. (But see my caveat below. Also, 200dpi doesn't look bad
either, but not nearly as good as 300dpi). For a 24"x36" print, then,
you need

7200x10800 or 77Mpix

for a great print, or

24x36x4000 or 34Mpix

for a good print.

Even most 35mm film has trouble coming up with 77Mpix of image data,
but medium format does very well.

The biggest fallacy here is that scanned pixels are much less clean
than digital-original pixels.

The other one is that some big prints fail to look good because of grain,
and others fail to look good because of lack of detail. (Then there's
the ones that fail to look good because of lousy printing, or a bad
original photo, but I think we can skip those, since we're talking
about technical potential here.) Digital originals will, generally
speaking, never fail to look good because of grain. They may,
however, fail to look good because of lack of detail; depending on the
subject matter, style of photo, and degree of enlargement.

So what "works" is highly variable. I've got a 16x24 print from a
Fuji S2 original that looks far better than any print in that size
range I ever made from a 35mm negative. (Which is partly just support
for your claim that medium-format film will more reliably produce
prints that size than 35mm film will.)

[...] I asked the sales guy about the quality of the lenses, and he
said they were worse on the MF, because poor quality lenses wouldn't
be as noticeable on MF! Is this true? If so, it seems I should just

It is technically true that a minor defect on a MF lens will be less
of a problem than a minor defect on a 35mm or dSLR lens, because the
defect contributes to less of the picture on MF than on smaller
formats. But don't be misled. A good MF setup can produce much
crisper enlargements than anything a 35mm camera can.

Of the same size, yes. However, that MF lens has a lower resolution.

Caveat: When I say that a good print requires 300dpi of information,
I'm talking about a good, sharp, print. I have 12x18 enlargements
from my 3Mpix camera which I love, but with only about 120dpi, they
more resemble impressionist paintings than photographs.

I have 8.5x11 prints from my old 2Mpix camera, slightly cropped, and
from a housemate's different old 2Mpix camera, that I've put into
stacks with darkroom prints to show to serious photographers who use
MF and do their own darkroom work, and nobody has complained about
lack of resolution, and many people have commented on what strikingly
nice prints they are. The lowest ended up being 107PPI if I'm
remembering correctly.

Mind you, I'd *never* suggest as a rule of thumb that 107PPI is
adequate printing resolution! But with the right photos sometimes it
works surprisingly well (this one was a very sharp insect macro shot;
not something I'd have expected to print well with inadequate
resolution at all). What I *would* suggest is that, if you have a
picture that you'd love to see twice as big as the numbers say you can
make it -- give it a try. *Sometimes* it'll actually work anyway, and
then you've got a great print you didn't think was possible. The rest
of the time you've wasted some paper and ink.
--
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/

Inaccessible wrote in newsandemonium-
:

No you do. IMOP.

eh?

It is cleaner to detect the digital image directly instead
of first using some electrochemical method. That is a
trivial truth. The smooth pictures you get from high end
digital cameras is a kind of proof. Film is grainy and have
low fidelity.

Of course a large format camera with superb lenses is
much, much better than any digital camera. But at the same
size film sux. And even medium format film has problems
with graininess compared to DSLRs.


/Roland

wrote in message
oups.com...
Hey folks -

I was looking at picking up a used MF camera in my area ( ~ $500 ) and
the sales guy was giving me a hard pitch on the digital cameras they
have in stock. Specifically he was harping on the Canon 10D. He showed
me a print that was larger than 2' in both dimensions that was made
from the canon, and I was impressed. When you looked at it very
closely, you saw what looked like weird Quake texture maps, but with
film you would see grain, I guess, so it seems an even trade off.

Anyway, my original thought was to buy a MF camera ( I like working
with film and holding a mechanical device in my hands ) and buy a
digital back for it later on when the prices fell. I asked the sales
guy about the quality of the lenses, and he said they were worse on the
MF, because poor quality lenses wouldn't be as noticeable on MF! Is
this true? If so, it seems I should just go digital. ( or maybe try to
get a deal on a used MF camera if I finance a digital -- I'll bet the
sales guy makes more money of a new digital than a used MF. )

Interesting question. When I did this for a living full-time I had a 35mm,
a Hassleblad and a 4x5. The 4x5 was just too big, and the Hassleblad
produced stunning photos, but was a pain to carry around with a bunch of
lenses and backs. I always kept gravitating back to the 35 and never
regretted it. The vast majority of shots were more than good enough for any
use, and it was expecially great for action photography.

Now, having experienced the world of digital slr, I can only say that when I
blow up an image to the equivalent of a 16x20 or more, it is possible to get
an image that looks as good or better than 35mm film, and that's at 6.1
megapixels. I can make "noise" look like film grain with a tweak here and
there.

While the idea of a medium format digital looks great on paper, they are
extremely expensive right now, and if you buy a camera that does not yet
have a digital back, you have no guarantee they will ever make a digital
back for that model. And if they do, what are the odds it will cover the
same area as the original film size? Look at what's happened to most
DSLR's, and many think that will be the "new" format for digital SLR's,
which lenses to match the fact that the coverage area is smaller.