How many megapixcels equivalent to 35 mm in quality

But digital suffers from certain statistical limitations that occur
with any sampled image process. Turns out grain also has a statistical
limitation. In both cases the result is a limitation to resolution,
or another MTF factor. So in effect, grain is a random sampling
process and a digital image is a regularly sampled (array) image. The
quantitative results are not exactly the same, but quite close.

A rectangular sampling array results in virtually identical
statistical limitations as the Kell factor.

>
> Digital does not have grain.
>

> Doug McDonald

Don Stauffer in Minnesota

Scott W <> wrote:
> On Jun 9, 9:29?pm, Fred McKenzie <fm...@aol.com> wrote:
>> In article <2oWdncoAte0_OtDVnZ2dnUVZ_tajn...@giganews.com>,
>> ?"David J. Littleboy" <davi...@gol.com> wrote:
>>
>> > In real life, most people who acquired a 6MP dSLR never shot 35mm again, and
>> > people who acquired a 12.7MP dSLR never shot 645 again.
>>
>> David-
>>
>> The cross-over point for me was one megapixel. ?After that, the only
>> reason I shot 35mm was because I needed the longer lens (500mm f/8 AF
>> mirror) for Space Shuttle launches. ?Now that I have the Sony A100, I
>> can use that lens digitally. ?I live about 15 miles from the launch
>> site, and have captured tiny images of the booster rockets flying away
>> from the shuttle about 80 miles down range.
>>
>> I switched because it gave me the capability of processing my own images
>> digitally. ?It was NOT because digital images were better than film
>> images, although that may be true for the A100 vs 35mm Kodacolor 400!

> My use of 35mm film took a big dip when I got a 1 MP camera, but 35mm
> film could beat it for image quality ease. Once I got my 3.2 MP
> digital my 4x6 prints from it looked far better then my 4x6 inch
> prints from my film camera, 35mm film could still capture more
> detail. But at a 4x6 inch print 3.2 MP is more then enough resolution
> and the fact that I could control the print gave me far better
> prints. Mini-labs could turn out prints from 35mm film that looked
> like they were taken with a 640x480 camera.

The crossover point for me came with a 3MP digital camera. JUst used
as a general purpose snapshot camera it usually produced better
sharper more enlargeable images than my 35mm SLR used in the same
carefree way. But when I used my SLR carefully to get the best from it
the superiority of the SLR was clearly evident at A4 print size
(approx 8"x11").

Careful examination of both kinds of images suggested that getting
around twice the linear resolution (i.e. 9MP) would probably bring
digital images to the same level of quality for me. So decided that at
least 9MP would be my next jump in digital quality, and I waited until
that size of sensor well enough established that goodish ones were
available second hand.

My next digital camera, a 10MP model which also had various other
later improvements (such as a very good lens) can easily produce
better images than I could ever get out of my old film SLR. I find I
have to crop off about half the image (i.e. crop down to a 5MP image)
to make a good match between my best film quality and my best digital
quality.

> Once I had a 8MP camera it was game over for 35mm for me. I did some
> tests and found that film could still capture just a bit more detail,
> but when comparing prints the print from digital looked sharper.
> Whereas 35mm film can capture finer detail it can only do so with very
> high contrast detail, like test charts. For real world scenes digital
> seems far better at capturing subtle detail. Just because you might
> need say 12MP to capture everything that is on film in no way means
> that you need a 12MP digital camera to match the image quality of
> film.

Of course neither my old SLR nor my new digital camera were top range
models even in their prime, just good budget conscious models for the
serious amateur who can't afford the best. But the megapixel
equivalence figures I found for my cameras the way I used them do seem
fairly close the kind of figures many others report. At 3MP I'd pull
out the old film SLR for occasional special high quality purposes. Now
with 10MP and other improvements on the digital side there's no point in
me ever using it again.

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Chris Malcolm

"Roger N. Clark (change username to rnclark)" wrote:
>
> David J. Littleboy wrote:
> > <> wrote:
> >
> > ?? But I am specifically referring to resolution only here. I
> > addressed the topic of dynamic range elsewhere in that post, and of
> > course you are right that most transparency film is contrasty and has
> > very limited drange.
> >
> > A nailed K25/Velvia slide (with good technique) will clearly outrun an
> > 8Mp image in terms of detail/resolution.
> > Here, the much quoted Roger Clark site indicates he puts Vevlia at
> > between 10 and 16 Mp.
> > http://www.clarkvision.com/imagedeta....summary1.html
> > <<<<<<<<<<<<<<<
> >
> > That's not been my experience.
>
> Having been alerted to this thread (I haven't been reading this
> newsgroup), I see my work is being misrepresented.

<heavily edited for brevity>

Hello, Roger:

Where've you been, these past few months, man? Did you allow all
those trolls and spammers to chase you away, perhaps?


Cordially,
John Turco <>

John Turco

"David J. Littleboy" wrote:

<edited for brevity>

> In real life, most people who acquired a 6MP dSLR never shot 35mm again,
> and people who acquired a 12.7MP dSLR never shot 645 again.
>
> David J. Littleboy
> Tokyo, Japan


Hello, David:

Hell, my Kodak V603 is a 6MP >subcompact< model, and it produces better
4x6 prints, than any of the P&S film cameras that I used, in the 1980's.

All right, allow me to qualify the above statement, a bit. I'd shot a few
rolls, with a Kodak "Pony" and an Argus C3; these were 35mm "precision"
puppies, having coated lenses and fully manual controls.

The Pony and C3 >could< match the V603 (and my other digicams, most of
which are Kodaks), provided that they were set, correctly. Alas, this was
no easy task, for a casual snapshooter, such as myself.

My C3 featured a coupled rangefinder, at least (whereas, the Pony lacked
an RF of any kind). Although, I did happen to own a light meter, which did
help somewhat, with exposure adjustments.

As for my Pentax K100D (6MP DSLR), the party's over! I'm fairly sure it
would annihilate any film camera I've ever handled. (In fact, I had one
of its images made into an 8x10 print, and it was mighty fine.)


Cordially,
John Turco <>

John Turco

"Tzortzakakis Dimitrios" <> wrote:
> So, it's digital compact->35 mm compact, dSLR->35 mm SLR, FF dSLR->film
> medium format.

I don't think you can compare it quite like that, since my 35mm Olympus
Myu-II compact was just as good as my 35mm SLR in actual picture quality,
whilst a digital compact will have a much smaller sensor than a DSLR so
it's S/N ratio will never be as good even if the megapixels are the same.

I would say that digital compacts have captured the market that 35mm had
back when medium/large format was the norm, and the compact v. DSLR wars
are basically a re-enactment of the 35mm v. medium/large format wars, and
hinge on the same kinds of issues like portability and spontaneity. I do
not see Cartier Bresson using a DSLR, whilst I can see him using a digital
compact, and this is precisely what his modern contempories are using. When
you consider that DSLRs are bigger and heavier than 35mm SLRs were at their
peak, it makes sense to think of them as the new medium format camera, and
that is also probably a reasonable take on their picture quality.

So I would say:

good digital compact = 35mm quality (both compact and, apart from
interchangeable lenses, SLR)

DSLR = medium format quality and 35mm SLR flexibility

Marty Fremen

On Tue, 10 Jun 2008 20:04:11 +0000, Dave Martindale wrote:

> Stefan Patric <> writes:
>
>>This thread has never been about whether digital is better than film,
>>scanned or not, only about establishing a fair test to find equivalence
>>one to the other.
>
> But what does "equivalence" mean in this case? The film and digital
> camera images will not be identical, no matter what resolution the
> digital image, because their MTF curves have different shapes. The
> digital image will preserve higher contrast at low and moderate spatial
> frequencies compared to the film, while the film is likely to resolve
> more line pairs per mm, at least compared to 6-8 MP DSLRs. For some
> subjects, the higher contrast at lower frequency will look subjectively
> better, for other subjects the film may contain more visible detail.

Right! Film != digital. Two very different animals each with their own
advantages, disadvantages, and differences. It's just two vastly
different methods of obtaining the same thing, an image that satisfies
one's requirements.

The prickly problem is to choose a color negative film (I'm going to be
making color prints for evaluation) that comes closest to matching the
gamma of the 4 or 5 stop range centered around 18% grey of the digital
camera's MTF curve. Since I can't change the film's parameters, it
probably will require that the digital camera's internal settings for
contrast, saturation, sharpness, etc. be adjusted to match the film as
closely as possible.

> You could objectively determine how many pixels are necessary to have
> the same resolution limit as a given film, but that's far more pixels
> than are needed to make the digital image look better most of the time.
> So most people would not call that "equivalence".

Actually, it's the lens that's the major limiting factor as far as image
resolution is concerned not the film. Film can and always has been able
to resolve more even if the lens can't deliver it. However, I'm more
concerned with practical, real world results than strictly scientific
testing. Besides, I don't have any resolution charts. And my tests
won't involve scanning the film.

> What do you mean by the word?

Let me answer that with a question: Is the English game of cricket
equivalent to American baseball? Certainly, they are not "equal," but
they could be called equivalent, since they both involve leagues, teams,
players, a ball, a bat, running, scoring, spectators, sports
commentators, etc., and comparisons can be made between the two.

>>The object is to establish an equitable testing method, and not have a
>>work flow that will give an unfair advantage to either media.
>
> So how will you create an equitable measure of "equivalent quality"?
> Without one, you can't have an equitable test.

You're thinking too much like a scientist. Think like an artist: If it
looks the same or better or worse, then it is.

I'm merely trying to determine to my satisfaction at what point silver-
based, color prints directly made from each type of camera, without any
"post" other than overall color and density adjustments, are for
practical purposes indistinguishable as to which system was used to
produce the image. At that point, there is equivalence.

Stef

Stefan Patric

On Jun 15, 1:25*pm, Stefan Patric <n...@thisaddress.com> wrote:
> On Tue, 10 Jun 2008 20:04:11 +0000, Dave Martindale wrote:
> > Stefan Patric <n...@thisaddress.com> writes:
>
> >>This thread has never been about whether digital is better than film,
> >>scanned or not, only about establishing a fair test to find equivalence
> >>one to the other.
>
> > But what does "equivalence" mean in this case? *The film and digital
> > camera images will not be identical, no matter what resolution the
> > digital image, because their MTF curves have different shapes. *The
> > digital image will preserve higher contrast at low and moderate spatial
> > frequencies compared to the film, while the film is likely to resolve
> > more line pairs per mm, at least compared to 6-8 MP DSLRs. *For some
> > subjects, the higher contrast at lower frequency will look subjectively
> > better, for other subjects the film may contain more visible detail.
>
> Right! Film != digital. *Two very different animals each with their own
> advantages, disadvantages, and differences. *It's just two vastly
> different methods of obtaining the same thing, an image that satisfies
> one's requirements.
>
> The prickly problem is to choose a color negative film (I'm going to be
> making color prints for evaluation) that comes closest to matching the
> gamma of the 4 or 5 stop range centered around 18% grey of the digital
> camera's MTF curve. *Since I can't change the film's parameters, it
> probably will require that the digital camera's internal settings for
> contrast, saturation, sharpness, etc. be adjusted to match the film as
> closely as possible.
Your not trying to say that a digital is limited to 4 or 5 stops are
you?


> > You could objectively determine how many pixels are necessary to have
> > the same resolution limit as a given film, but that's far more pixels
> > than are needed to make the digital image look better most of the time.
> > So most people would not call that "equivalence".
>
> Actually, it's the lens that's the major limiting factor as far as image
> resolution is concerned not the film. *Film can and always has been able
> to resolve more even if the lens can't deliver it. *However, I'm more
> concerned with practical, real world results than strictly scientific
> testing. *Besides, I don't have any resolution charts. *And my tests
> won't involve scanning the film.
Even a cheap lens will out resolve film, at least if it is stopped
down and you are viewing the center of the field. I use a Canon 350D,
which has a pixel spacing of right around 4000 pixels/inch. I get far
sharper images at the pixel level with the digital then I ever got
from a 4000 ppi film scan. And I have gotten sharper prints by first
scanning a negative and printing from that compared to a wet print. I
can also use a 1.4x teleconverter and still get a sharp image at the
pixel level, that would be close to scanning film at 5600 ppi, 4000ppi
film soft but 5600 ppi film scan are super soft, when viewed at the
pixel level.

Now I can tell you are going to tell me it is the scanning that is at
fault, but I have seen just one film that really does show the
resolution of a decent lens, Gigabit film. Here is a scan that Max
Perl did using this film.
http://www.terrapinphoto.com/jmdavis..._crop_1000.jpg
A very impressive scan.
So how does the scam equipment do with a color film, not even close to
as good.
http://www.terrapinphoto.com/jmdavis..._crop_1000.jpg
If the same scanner can pickup great detail with Gigabit film it
should be able to do the same with color film, if the detail was
really there. Clearly the color film is not coming close to capturing
all the detail that the lens produces.


> > What do you mean by the word?
>
> Let me answer that with a question: *Is the English game of cricket
> equivalent to American baseball? *Certainly, they are not "equal," but
> they could be called equivalent, since they both involve leagues, teams,
> players, a ball, a bat, running, scoring, spectators, sports
> commentators, etc., and comparisons can be made between the two.
>
> >>The object is to establish an equitable testing method, and not have a
> >>work flow that will give an unfair advantage to either media.
>
> > So how will you create an equitable measure of "equivalent quality"?
> > Without one, you can't have an equitable test.
>
> You're thinking too much like a scientist. *Think like an artist: If it
> looks the same or better or worse, then it is.
>
> I'm merely trying to determine to my satisfaction at what point silver-
> based, color prints directly made from each type of camera, without any
> "post" other than overall color and density adjustments, are for
> practical purposes indistinguishable as to which system was used to
> produce the image. *At that point, there is equivalence.
I will be interested to here what you conclude.

Scott

Scott W

Marty Fremen wrote:
> "Tzortzakakis Dimitrios" <> wrote:
>> So, it's digital compact->35 mm compact, dSLR->35 mm SLR, FF dSLR->film
>> medium format.
>
> I don't think you can compare it quite like that, since my 35mm Olympus
> Myu-II compact was just as good as my 35mm SLR in actual picture quality,
> whilst a digital compact will have a much smaller sensor than a DSLR so
> it's S/N ratio will never be as good even if the megapixels are the same.
>
> I would say that digital compacts have captured the market that 35mm had
> back when medium/large format was the norm, and the compact v. DSLR wars
> are basically a re-enactment of the 35mm v. medium/large format wars, and
> hinge on the same kinds of issues like portability and spontaneity. I do
> not see Cartier Bresson using a DSLR

I don't know, he might choose a D50 with a 20mm f/2.8 (or similar), I
would if I did all street shooting. While it does make some noise, it's
probably smaller & lighter than those old rangefinders.

>, whilst I can see him using a digital
> compact, and this is precisely what his modern contempories are using. When
> you consider that DSLRs are bigger and heavier than 35mm SLRs were at their
> peak, it makes sense to think of them as the new medium format camera, and
> that is also probably a reasonable take on their picture quality.
>
> So I would say:
>
> good digital compact = 35mm quality (both compact and, apart from
> interchangeable lenses, SLR)
>
> DSLR = medium format quality and 35mm SLR flexibility
>


--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Paul Furman

Stefan Patric <> writes:

>Right! Film != digital. Two very different animals each with their own
>advantages, disadvantages, and differences. It's just two vastly
>different methods of obtaining the same thing, an image that satisfies
>one's requirements.

>The prickly problem is to choose a color negative film (I'm going to be
>making color prints for evaluation) that comes closest to matching the
>gamma of the 4 or 5 stop range centered around 18% grey of the digital
>camera's MTF curve. Since I can't change the film's parameters, it
>probably will require that the digital camera's internal settings for
>contrast, saturation, sharpness, etc. be adjusted to match the film as
>closely as possible.

But isn't that a biased test? You're taking the "film look" as a
standard, and attempting to adjust the digital camera to match it as
closely as possible. That's likely to compromise some or all of the
advantages of the digital image (e.g. higher contrast at low spatial
frequencies) compared to film, while leaving film at its optimum.

It seems to me that if you're doing subjective tests, you should adjust
the digital camera for subjectively best images - not images that match
film as closely as possible.

>> You could objectively determine how many pixels are necessary to have
>> the same resolution limit as a given film, but that's far more pixels
>> than are needed to make the digital image look better most of the time.
>> So most people would not call that "equivalence".

>Actually, it's the lens that's the major limiting factor as far as image
>resolution is concerned not the film. Film can and always has been able
>to resolve more even if the lens can't deliver it. However, I'm more
>concerned with practical, real world results than strictly scientific
>testing. Besides, I don't have any resolution charts. And my tests
>won't involve scanning the film.

>Let me answer that with a question: Is the English game of cricket
>equivalent to American baseball? Certainly, they are not "equal," but
>they could be called equivalent, since they both involve leagues, teams,
>players, a ball, a bat, running, scoring, spectators, sports
>commentators, etc., and comparisons can be made between the two.

I would never call them equivalent except in the vaguest sense. But I
have no incentive to compare one to the other; I don't watch either.

>> So how will you create an equitable measure of "equivalent quality"?
>> Without one, you can't have an equitable test.

>You're thinking too much like a scientist. Think like an artist: If it
>looks the same or better or worse, then it is.

Ok, then you probably should call your test "subjective" rather than
"equitable". And the results you get are going to depend a lot on the
content of the image.

>I'm merely trying to determine to my satisfaction at what point silver-
>based, color prints directly made from each type of camera, without any
>"post" other than overall color and density adjustments, are for
>practical purposes indistinguishable as to which system was used to
>produce the image. At that point, there is equivalence.

And I'd argue that this will be very elusive. Unless you deliberately
cripple the digital images, for many subjects the higher contrast at
lower spatial frequency of the digital image will make it look "better"
even while its limiting resolution is far below that of the film you're
comparing against. The digital pixel count at which "as good or better"
happens will depend on the image content, print size, and viewing
distance. So I don't think you'll ever get a single number that's very
useful for predicting "equivalent quality".

You might be able to establish a set of numbers, each for a pretty
restricted domain. For example, "For landscape photography where prints
are 2 ft x 4 ft and the viewing distance is 2 ft, an X megapixel digital
camera is subjectively equivalent to film Y recording a 24x36 mm image".

Dave

Dave Martindale

On Jun 16, 10:10*am, da...@cs.ubc.ca (Dave Martindale) wrote:
> Stefan Patric <n...@thisaddress.com> writes:
> >Right! Film != digital. *Two very different animals each with their own
> >advantages, disadvantages, and differences. *It's just two vastly
> >different methods of obtaining the same thing, an image that satisfies
> >one's requirements.
> >The prickly problem is to choose a color negative film (I'm going to be
> >making color prints for evaluation) that comes closest to matching the
> >gamma of the 4 or 5 stop range centered around 18% grey of the digital
> >camera's MTF curve. *Since I can't change the film's parameters, it
> >probably will require that the digital camera's internal settings for
> >contrast, saturation, sharpness, etc. be adjusted to match the film as
> >closely as possible.
>
> But isn't that a biased test? *You're taking the "film look" as a
> standard, and attempting to adjust the digital camera to match it as
> closely as possible. *That's likely to compromise some or all of the
> advantages of the digital image (e.g. higher contrast at low spatial
> frequencies) compared to film, while leaving film at its optimum.
>
> It seems to me that if you're doing subjective tests, you should adjust
> the digital camera for subjectively best images - not images that match
> film as closely as possible.
>
> >> You could objectively determine how many pixels are necessary to have
> >> the same resolution limit as a given film, but that's far more pixels
> >> than are needed to make the digital image look better most of the time.
> >> So most people would not call that "equivalence".
> >Actually, it's the lens that's the major limiting factor as far as image
> >resolution is concerned not the film. *Film can and always has been able
> >to resolve more even if the lens can't deliver it. *However, I'm more
> >concerned with practical, real world results than strictly scientific
> >testing. *Besides, I don't have any resolution charts. *And my tests
> >won't involve scanning the film.
> >Let me answer that with a question: *Is the English game of cricket
> >equivalent to American baseball? *Certainly, they are not "equal," but
> >they could be called equivalent, since they both involve leagues, teams,
> >players, a ball, a bat, running, scoring, spectators, sports
> >commentators, etc., and comparisons can be made between the two.
>
> I would never call them equivalent except in the vaguest sense. *But I
> have no incentive to compare one to the other; I don't watch either.
>
> >> So how will you create an equitable measure of "equivalent quality"?
> >> Without one, you can't have an equitable test.
> >You're thinking too much like a scientist. *Think like an artist: If it
> >looks the same or better or worse, then it is.
>
> Ok, then you probably should call your test "subjective" rather than
> "equitable". *And the results you get are going to depend a lot on the
> content of the image.
>
> >I'm merely trying to determine to my satisfaction at what point silver-
> >based, color prints directly made from each type of camera, without any
> >"post" other than overall color and density adjustments, are for
> >practical purposes indistinguishable as to which system was used to
> >produce the image. *At that point, there is equivalence.
>
> And I'd argue that this will be very elusive. *Unless you deliberately
> cripple the digital images, for many subjects the higher contrast at
> lower spatial frequency of the digital image will make it look "better"
> even while its limiting resolution is far below that of the film you're
> comparing against. *The digital pixel count at which "as good or better"
> happens will depend on the image content, print size, and viewing
> distance. *So I don't think you'll ever get a single number that's very
> useful for predicting "equivalent quality".
>
> You might be able to establish a set of numbers, each for a pretty
> restricted domain. *For example, "For landscape photography where prints
> are 2 ft x 4 ft and the viewing distance is 2 ft, an X megapixel digital
> camera is subjectively equivalent to film Y recording a 24x36 mm image".


I am not sure there is a good alternative to comparing prints, it is
clearly not an objective test but there really is no objective test
that I know of that really works.

A friend and I did the print test 4 years ago, he shot with his
favorite film and I used my digital. It was hard to judge the images
just looking at pixels, but when looking at the prints we both though
the digital image looked a bit sharper. I believe that was the last
roll of film he shot. I was using my Sony F828 at the time, which has
8MP but is not nearly as sharp as a decent 8MP DSLR.

For him this test gave a good idea of what he needed in a digital
camera to match what he was getting with 35mm film, and that was the
whole point in doing the test. BTW he was using a Nikon CoolScan V
ED, I don’t remember the film he used, the camera was a Nikon with a
prime lens.

I have heard a lot of arguments about scanners degrading the image
quality but I have yet to see anyone give evidence that this is the
case. I have heard people say you need a drum scanner to really get
everything out of film, but drum scans at 4000ppi look just as bad as
CCD film scanners at 4000ppi. So I don’t really buy Stefan’s claim
that an optical print would be notable sharper then one from a scan.

Scott

Scott W