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Film and digital resolution compared
Old 11-18-2013   #1
RichC
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Film and digital resolution compared

It is commonly stated on the internet that a good 35 mm frame of ISO 100 film has a resolution equivalent to 20-25 MP. However, although this figure has some truth to it, it does not reflect what we find when film and digital are compared in real life. Unfortunately, every test I’ve encountered on the web has serious flaws – the fact that the comparisons contradict each other in every detail bears witness to this. So, the answer was to do my own investigation...


I'd be interested if anyone can find any major flaws in my argument.These calculations are of course somewhat crude, but suffice to give ballpark figures.


What none of these web comparisons addresses is the need to consider bottlenecks in equipment that impact the theoretical resolution of film – i.e. lens resolution and scanner resolution (assuming images will be scanned). Consider a typical scan of 35 mm film at a scanner resolution of 2700 ppi: the resulting file has dimensions of about 3800 × 2400 pixels = 9 MP – but this is not equivalent to a 9 MP image from a digital camera because both are theoretical values based solely on the number of pixels, and fail to account for differences in resolving power between the two mediums. Comparing, say, a 20 MP film scan with a 20 MP digital camera image is thus comparing apples with oranges. What we actually need to compare is the resolving power of frame of film and a digital sensor.


Basically, the ad men and marketing executives have co-opted the term "resolution" to mean something far removed from its true meaning, thus sowing confusion. "Resolution" has little directly to do with pixels and file size, and is correctly "the ability of an optical instrument or type of film to separate or distinguish small or closely adjacent objects".


Resolution (in its correct sense of "resolving power") lis governed by the Nyquist–Shannon theorem. This states that the maximum frequency (the Nyquist frequency) that can be resolved without loss of information is half the sampling frequency. Applied to digital photography (both digital cameras and scanned film), the sampling frequency is the resolution of the sensor or film (measured in line pairs per millimetre, lp/mm), and the Nyquist frequency is the resolution in megapixels (MP) needed to resolve all the information recorded by the sensor or film. Thus,

R = (2rh × 2rw)/10^6 = 4r^2hw/10^6

where r is the recorded resolution of the sensor or film (measured by experiment), h is the height of the sensor or film, w is the width of sensor or film, and R is the sensor or scanner resolution in MP needed to resolve the recorded detail.

(Note: I can't type superscripts, so ^ denotes that the following number is a superscript, e.g. 10^6 = 10 to the power 6.)



The real-world resolution of a digital sensor

We need to know how much a typical 35 mm full-frame dSLR can resolve. Rather than consider a top-line camera, let’s consider something more affordable – the Canon 5D Mark II. It’s a 21 MP camera, but this is not a direct measure of its resolution – it’s simply the number of pixels it records. Tests (see DPReview) show that this dSLR has a resolution of about 58 lp/mm. From our equation,

R = (4 × 58^2 × 24× 36)/10^6 ~12 MP



35 mm film

Typical professional 100 ISO colour negative film (Kodak Extar, etc.) has a resolution of about 70 lp/mm (as measured in tests – see film manufacturers’ websites), which is about the same as a dedicated film scanner (not a flat-bed scanner – which destroys resolution – even the best like the Epson V750 cuts this by half, to ~35 lp/mm). The formula gives

R = (4 × 70^2 × 24× 36)/10^6 ~ 17 MP

35 mm colour film thus records a little more detail than most 35mm full frame dSLRs. However, 35 mm colour film has a lot of ‘noise’ (i.e. grain), so that, visually, the smoother-looking dSLR image is preferred by most people, despite having slightly less visible detail overall. (Low-ISO B&W film has much higher resolution and less grain, and can show more detail than medium-format digital backs.)



Medium-format film

The formula gives the following for 645-format film, if we assume medium-format lenses resolve equally to 35 mm lenses:

R = (4 × 70^2 × 45× 60)/10^6 ~ 53 MP

And, for the 6×7 format:

R = (4 × 70^2 × 60 × 70)/10^6 ~ 82 MP

A typical digital back such as the 65 MP Phase One P65+ will resolve about 45 MP.

Large-format film


Turning to 4×5 film, the formula gives a resolution of

R = (4 × 70^2 × 100 × 125)/10^6 ~ 245 MP



Not the whole story...

Lens diffraction and depth of field
We need our photographs from the various formats to appear identical if we are to compare them: this means the same view and the same depth of field. A ‘standard’ (i.e. equivalent to the 50 mm lens used with the 35 mm format) medium-format lens is 80 mm – call it twice the focal length, for convenience. The 150 mm ‘standard’ lens used for large format is three times longer. The depth of field for medium and large format to match that of a 50 mm lens is obtained by multiplying the aperture by the relative increase in the focal length. If we assume the optimum aperture for resolution of f/5.6 for 35 mm film, then the medium- and large-format apertures giving an equivalent depth of field are

2 × f5.6 = f/11 (medium format)
3 × f/5.6 = f/16 (large format)

How does this affect resolution? Lens resolution changes with aperture, being at its optimum at f/5.6 for many lenses. The resolution will fall by 25% at f/11, 35% at f/16 and 50% at f/22 (e.g. see the lens reviews at DPReview). So, the resolution of 4×5 film used at a real-world aperture can thus be as low as ~ 175 MP.

Taking depth of field into account, our film resolutions become

R = 17 MP (35 mm)
R = 53 × 0.75 = 40 MP (645)
R = 82 × 0.75 = 62 MP (6×7)
R = 245 × 0.65 = 160 MP (4×5)

Scanning
Scanning film will reduce the resolution further, from manufacturers’ data. A good drum scan will result in a degradation of about 80%, so the above resolution are now


R = 14 MP (35 mm)
R = 42 × 0.75 = 32 MP (645)
R = 66 × 0.75 = 49 MP (6×7)
R = 196 × 0.65 = 127 MP (4×5)

As mentioned above, flat-bed scanners are awful for scanning film, reducing these resolution by half.

Contrast and grain
Digital photographs look sharper than photographic prints because of their greater edge contrast (which is what you enhance when ‘sharpening’ a digital image) and lack of grain. Let’s knock off an arbitrary 5 MP for ISO 100 digital and film images, to account for the ‘cleaner’ look of digital photographs. So, our final resolutions are now

R = 9 MP (35 mm)
R = 27 MP (645)
R = 44 MP (6×7)
R = 122 MP (4×5)


Note: these values should not be compared with manufacturers' sensor resolutions – those simply tell us how many pixels a sensor has, not how much information is recorded, i.e. the true resolution. They need to be compared with sensor resolutions obtained using the Nyquist–Shannon formula. Here are the "true" resolutions of a few digital cameras (the recorded resolution r is obtained from measurements of test charts by DPReview):

21 MP Canon 5D Mk II and Mk III
r = 58 lp/mm
R = 4r^2hw/10^6
R = (4 × 58^2 × 24× 36)/10^6 ~12 MP

18 MP Leica M9
r = 62 lp/mm
R = (4 × 62^2 × 24× 36)/10^6 ~13 MP

36 MP Nikon D800E
r = 102 lp/mm
R = (4 × 102^2 × 24× 36)/10^6 ~36 MP

(The measured resolution of the Nikon D800E is astonishing, matching the quoted (pixel) resolution of 36 MP, and outresolving DPeview's test chart, which tops out at 83 lp/mm.)

__________________________________________________ _

In summary, full-frame digital cameras of about 20 MP match the resolution of professional 100 ISO 35 mm colour film scanned on a dedicated film scanner, while cameras using Sony's 36 MP sensor such as the Nikon D800E match the resolution of 645 medium-format film. A 50 MP digital can match 6×7 film, but large-format film still outperforms the best digital camera by a wide margin.
__________________________________________________ _

Printing
Traditional darkroom prints made from film in an enlarger appear significantly less sharp than digital prints from scanned film: first, limitations from the apparatus – the enlarger and paper must be perfectly parallel, and this becomes more critical the larger the print, and that the lens itself degrades the image; secondly, scans can be made ‘sharper’ by adjusting the edge contrast – which cannot of course be done when printing directly from film.

The sharpest film print is thus digital, despite the loss in resolution from scanning: for best quality, we should scan the film and obtain a C-type or inkjet print – not use an enlarger.

Inkjet prints are slightly sharper and more expensive than C-type prints, but C-types are more robust and are a traditional silver-based photographic medium (if that’s important to you). Also, C-types have a different look to inkjet prints (that's different not better!) – the pigment in C-types sits in the surface, not on the surface, which gives them a subtle depth and three-dimensionality.

So, sharpness vs subtleness of depth – you can only have one!
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Last edited by RichC : 11-20-2013 at 02:06. Reason: Various typos corrected - as per the posts below. Thanks
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Old 11-18-2013   #2
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A very careful analysis; thank you. Gonna have to go chew on this one for a while ...
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Old 11-19-2013   #3
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So, no replies - presumably, then, you all agree with me!
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Old 11-19-2013   #4
lam
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Wow, I just had a read and thank you for your careful analysis and breakdown.
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Old 11-19-2013   #5
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there is no such a thing as film. film is a generic term used to describe the many types of emulsions with varying characteristics that is used for capturing photos.

whenever you compare film with anything, you have specify, which film you're using for the test.
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Old 11-19-2013   #6
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Post of the year. Thanks for tackling a hard subject so objectively.
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Old 11-19-2013   #7
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Quote:
Originally Posted by Margu View Post
there is no such a thing as film. film is a generic term used to describe the many types of emulsions with varying characteristics that is used for capturing photos.

whenever you compare film with anything, you have specify, which film you're using for the test.
OK - I could have been more specific. The types of film I am examining are low-grain professional films. Kodak Extar 100 ISO would be typical. For the above calculations, it is unnecessary to be more specific, provided the film has a measured resolution of about 70 lp/mm, as additional information will not affect the calculations.
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Old 11-19-2013   #8
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All I need is someone with resolution test charts, cameras and a film scanner to test my theory now!
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Old 11-19-2013   #9
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Thank you, interesting reading. I am stuck in the dark ages with a Canon 5D classic for DSLR work, so not even on the map here and not in touch with sensor technology.

Out of interest, does Sony use the 36mp sensor elsewhere and does it match the D800E, or is Nikon doing something magical.
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Old 11-19-2013   #10
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FWIW, here's a link to Norman Koren's thoughts along the same lines from back when the Canon 5D was state of the art.

http://www.normankoren.com/Tutorials/MTF7.html

For myself, while my film scanner captures 4000dpi, I'm under no delusion that 4000 dpi are actually there.
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Old 11-19-2013   #11
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As to film resolution tests, see these done with a high-end Imacon scanner (not yet a drum scanner):

http://www.boeringa.demon.nl/menu_technic_ektar100.htm

Also slide films like Velvia 50/100 have higher resolution than Ektar 100.

After seeing Irving Penn's exhibition a month ago in Pace MacGill Gallery, I would disagree with your statement that darkroom prints are less sharp than digital ones.
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Old 11-19-2013   #12
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I would like to note, that the sharpness loss due to diffraction is not proportional to the F stop, but to the physical size of the diaphragm, therefore the I Phone lens will be suffering from diffraction at f 2.0, while a 350mm lens covering 8x10 will probably start feeling diffraction over f 32.
Moreover, as much as your reasoning might be correct, I feel digital cameras have TOO MUCH resolution, and NOT ENOUGH bit depth. I continue to have a revolting feeling in my stomach every time I see an average digital B&W image. If you really care about resolution only, take a 25 ISO repro film developed in one of the SPUR special developers, and then your calculations will have to be redone.
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Old 11-19-2013   #13
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Quote:
Originally Posted by mfogiel View Post
I would like to note, that the sharpness loss due to diffraction is not proportional to the F stop, but to the physical size of the diaphragm, therefore the I Phone lens will be suffering from diffraction at f 2.0, while a 350mm lens covering 8x10 will probably start feeling diffraction over f 32.
Moreover, as much as your reasoning might be correct, I feel digital cameras have TOO MUCH resolution, and NOT ENOUGH bit depth. I continue to have a revolting feeling in my stomach every time I see an average digital B&W image. If you really care about resolution only, take a 25 ISO repro film developed in one of the SPUR special developers, and then your calculations will have to be redone.
can you tell if an image, especially on the web, is digital or film?

i can't. in fact i saw the book of Daido Moriyama, The World Through My Eyes, and his images looked as if a child was playing with silver efex, although in hindsight it was his prints that inspired silver efex.

anyone who can tell film from digital on the internet and even quality prints has super eye powers.
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Old 11-19-2013   #14
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Quote:
Originally Posted by Margu View Post
can you tell if an image, especially on the web, is digital or film?

i can't. in fact i saw the book of Daido Moriyama, The World Through My Eyes, and his images looked as if a child was playing with silver efex, although in hindsight it was his prints that inspired silver efex.

anyone who can tell film from digital on the internet and even quality prints has super eye powers.
We need to get some samples in here and test....is it film or is it frigidal?
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Old 11-19-2013   #15
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Thank you for some answers to questions I've had for a while.

Excellent guide for selecting medium to use depending on intended final display to be employed.

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Old 11-19-2013   #16
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Quote:
Originally Posted by Ansel View Post
I think the pursuit of sharpness/resolution are a waste of time. A completely pointless pursuit. There is a lot more aesthetically that I am interested in and why I still shoot film.
+1, although I switched to digital.

I did not care to read and try to understand all of the OP's post (sorry RichC) but when I went digital RF I realized, how much of IQ is wasted in a film based system and you won't even recognize it unless you make test shots and real big enlargements.

Just a click 100% view on your digital images will be a revelation on any shortcomings of RF alignment, focus adjustment of your lens on the sensor plane and sloppy technique on the user part.

But basically a boring image remains a boring image even if technically, it might be a field day for pixel peepers.

Quote:
Originally Posted by mfogiel View Post
.... I continue to have a revolting feeling in my stomach every time I see an average digital B&W image. If you really care about resolution only, take a 25 ISO repro film developed in one of the SPUR special developers, and then your calculations will have to be redone.
LOL, the example of lowest ISO BW film developed in Spur is always the last resort also of Mr. Puts .
I totally agree that a lot of images displayed on the web (inheritly ALL of these are digital ) do have a certain digital look to them. Most of the times this involves over sharpened, high contrast treatment.
That mostly is a preference
a) of the person who processed and posted the image and
b) the recipients preferences and his monitor.

There is a lot of flexibility in how you can process an image and the final outcome is not necessarily determined by the type of capturing device.
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Old 11-19-2013   #17
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Since almost all semiconductors are still made with lithography you could argue that some film has much higher resolution than digital.
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Old 11-19-2013   #18
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There's a lot of guessing, estimating and wishful thinking in any of these comparisons, and yours is certainly one of the more rigorous, apart from confusing the M9 (18 MP) and the Typ 240 (24 MP. Like yopu, most of the people I've ever seen doing estimates point out that they rely on a lot of assumptions -- including the contrast of the test chart, and the difference between essentially random arrays (film) and regular arrays (digital). Unsurprisingly, most people's estimates come up with roughly similar figures -- "roughly similar" including, depending on the assumptions, figures differing by a factor of four. Your figures are pretty much in the middle...

Cheers,

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Old 11-19-2013   #19
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Quote:
Originally Posted by Margu View Post
can you tell if an image, especially on the web, is digital or film?

i can't. in fact i saw the book of Daido Moriyama, The World Through My Eyes, and his images looked as if a child was playing with silver efex, although in hindsight it was his prints that inspired silver efex.

anyone who can tell film from digital on the internet and even quality prints has super eye powers.
- It comes easier, if you are accustomed to seeing high quality film prints. BTW for what Moriyama does, it does not matter if he shoots film or digital, because he likes graphic images - his film and digital images suck all the same in the sense, that they exhibit compressed range of tones. I am not saying, this is wrong, but this is not classic B&W photography the same way as paper cutouts or collages stuck on canvas are not the same as a Rembrandt painting.
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Old 11-19-2013   #20
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Thank you for the great write up, tis very interesting on the resolution end of it, so I'll
have to work at getting a 20-24 mp digital camera now so at least I'll have a common
resolution that matches ISO 100.

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Old 11-19-2013   #21
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Short budget version.

Colors.
My 16MP 500D and 12MP 5Dc outperforms in terms of resolution (MPs) and noise my 1600 DPI V500 color film scans of 135 format.

But then I look at "Ansel Adams in colors" book...

B/W.
My 120 and 135 B/W then scanned by same V500 and printed at Costco visually outperforms my b/w digital.
Even before printing, just scans...


Quote:
Originally Posted by Margu View Post

...anyone who can tell film from digital on the internet and even quality prints has super eye powers.
Weird. I just wrote at another thread, how I gave film RF for young guy who could clearly see the difference in print.

I stopped watching closely Flickr groups with mixed media content.
Most of digital ones are too obvious and boring.
I personally prefer lomography to photoshop.
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Old 11-19-2013   #22
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Quote:
Originally Posted by RichC View Post
Resolution (in its correct sense of "resolving power") lis governed by the Nyquist–Shannon theorem. This states that the maximum frequency (the Nyquist frequency) that can be resolved without loss of information is twice the sampling frequency.
While I freely admit your math is beyond my capabilities, I did find one typo and thought I would point it out in case it causes any confusion: The Nyquist frequency is HALF the sampling frequency, not twice.
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Old 11-19-2013   #23
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Film is a marvelous medium to be sure. Permanence, dynamic range, aesthetic advantages I can't even begin to discuss.....

But the biggest thing, for me, is the ability to put some film in my Leica M2 and be completely confident I can take a picture
with that combination without dithering with menus, batteries, electronics or dust on a sensor.

I can even focus the thing all by myself!......Imagine!
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Old 11-19-2013   #24
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Quote:
Originally Posted by Margu View Post
can you tell if an image, especially on the web, is digital or film?

i can't. in fact i saw the book of Daido Moriyama, The World Through My Eyes, and his images looked as if a child was playing with silver efex, although in hindsight it was his prints that inspired silver efex.

anyone who can tell film from digital on the internet and even quality prints has super eye powers.
All photographic images viewed online are digital.

~Joe
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Old 11-19-2013   #25
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To be honest, I don't know enough about the technicalities of film or digital to make a meaningful contribution to this thread (but that won't stop me), these are however interesting comparisons:

Ektar 100 in 35mm against the 21MP 5D Mk II:

http://www.twinlenslife.com/2011/01/...ark-ii-vs.html

Ektar seems to have just a touch more resolution looking at the chap's wooly hat, but they are close enough to be considered equivalent I think.

Then we have 4x5 and 8x10 vs. a Phase One IQ180:

http://www.onlandscape.co.uk/2011/12...ra-comparison/

4x5 probably has a smidge more resolution, but a lot more grainy of course.
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Old 11-19-2013   #26
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I shoot both digital (5DmkII and leica X1) as well as 35mm film and 4x5 film.

I was able to enlarge scans of 35mm slide film to nearly four feet wide and have a good usable print, albeit not as sharp as smaller prints, but I was surprised how well they held up.

I used the Leica M6 with a Summicron 50 and the Minolta Dimage Elite 5400 scanner.

There's no way I could do this with the 5DmkII images, or even the D800 for that matter.



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Old 11-19-2013   #27
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Also, for those looking for very high resolution in B&W film, Kodak claim that BW400CN is "The world's finest-grained chromogenic film.", so presumably that includes any other C41 film like Ektar.

http://www.kodak.com/global/en/profe...cn/main2.jhtml
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Old 11-19-2013   #28
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Theoretically very interesting but two things come to mind regarding real world application 1) (lens) sample variation 2) camera shake. While the former might not have such a big impact anymore thanks to improved manufacturing techniques the latter is still limiting achievable sharpness to a large extend in real world photography.
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Old 11-19-2013   #29
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Quote:
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Theoretically very interesting but two things come to mind regarding real world application 1) (lens) sample variation 2) camera shake. While the former might not have such a big impact anymore thanks to improved manufacturing techniques the latter is still limiting achievable sharpness to a large extend in real world photography.
No question, I've taken handheld shots at 1/250 second with leaf shutter cameras and on full res scans I can sometimes see a touch of shake.
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Old 11-19-2013   #30
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Nearly all these discussions end up talking about scans of film. Given the difference in grain structure between digital (including scanning) and film, this will always be to the detriment of film, as information will be lost in the transfer. On the other hand, if the standard was a 35mm slide produced either directly or via reproduction from a digital file, this would be to the detriment of digital.

The only "fair" test, IMHO, would be prints derived from both processes.
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Assumptions
Old 11-19-2013   #31
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Assumptions

If you read Isaac Asimov's Foundation you'll come across a certain character whose notion of science is to carefully weigh the existing literature, balance the words of the greats, and write his own opus based on that. One of the Foundation folks asks him if he's considered empirical work.

Have you considered the possibility of one's digitizing the film by taking several 36MP photos of it at whatever desired magnification, using a slide copier, and then stitching the resulting files? I feel that picture would be worth 1k words.
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Old 11-19-2013   #32
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I find all these comparisons to be very interesting. I have read some very intelligent comparisons, and yours certainly fits in that category. Though my own grasp of all the technology is nowhere near the level of your own I personally see at least one issue that is always ignored in these comparisons.

First, the two are not the same. One is digital and the other is analogue. As such there is no convenient method of making any form of comparison without converting one to the other. Either the analogue image must be digitized, or the digital image must somehow be turned to analogue. Based on my limited understanding of pixels, the latter is not really possible. And the former always results in loosing some of the information contained in the film.

The second problem I have with this comes from my experience over the years with both technologies. In the early 2000s I was taking pictures with 3 megapixel digital cameras as well as with a Pentax LX and K1000 on film. Even with all the wondrous image manipulation technology available today, my old 3 megapixel images will never get any better. However, the negatives from that old Pentax K1000 can be scanned with the newest scanners and always seem to improve each time.

Everyone says that the newest digital cameras have finally exceeded the quality of film. My question though is this. What will my 2004, K1000 negatives look like when scanned in 10 years? And then how will that compare with the 36 megapixel image being captured today by the new Nikon D800?
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Old 11-19-2013   #33
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http://www.rangefinderforum.com/forums/showthread.php?t=138124

The OP did a wonderful job of explaining his theories.
I use film and digital.
First when i scan, either on my flat bed scanner,or have high "rez" done,
i feel it is a lousy way to look at film.
In plain language of our time "It sucks".
Digital even in low end point and shoot cameras appear sharper.
Therefor there is no need for high end cameras and sensors.
Those who "claim" making those huge enlargements, where are they stored?
Film is an archival system.
Digital is not.
Not now definitely not later.
If NASA cannot look at their older data, what chance have we?
A few weeks ago, my one drive sent all my images to Purgatory.
The year 2013. Gone.
I can look at images i shot on film going back decades.
I use digital for internet.
I am about to go back to wet darkroom.
Neither is perfect.
Film does not require upgrades in computers, software,
programs, devices every few hours..
Before you start "texting", see all your "updates".
This wheel of ever more purchasing cannot be sustained!
Hence the drop in sales of all photographic equipment.
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Old 11-19-2013   #34
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RichC, many thanks for posting an interesting, thoughtful, and balanced analysis. It's good to see someone looking into this, without having an axe to grind for one side or the other. Sadly, the reality (for me) is that the sheer convenience of digital wins... yes, lazy, I know.

On a more everyday level, another side of me agrees with Ansel's post (#12) i.e. that the pursuit of sharpness is something of a waste of time. In a good photograph ("good", of course, in the eye of the beholder), there's so much more to appreciate and enjoy than the technical performance of the lens/sensor/film. I've reached the point where I feel that if my attention is grabbed by the sharpness of an image, the image probably doesn't have much else to offer. Just MHO, of course.
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Old 11-20-2013   #35
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Just a quick response to various posts:

● My post is simply an attempt to answer the question "How many megapixels is a frame of film equal to?" It is about practical photography and affordable equipment, and what most people "into" photography such as us might use: i.e. full-frame digital SLRs and professional colour negative film such as Ektar or Portra.

● It goes without saying that fine-grained B&W film or an 80 MP digital Hasselblad will give exceptional tonality and detail - but let's stick with digital SLRs and colour negative film, if simply for the reason that this is my thread, this is the equipment I use, and I prefer colour photography!

● My post is most certainly not about whether film or digital is better - I use both, and prefer the look of film but the convenience of digital. My weapons of choice are a Mamiya 645 with Portra and a Nikon D800E - which give very similar results regarding tone and detail. (I print both up to 36 inches wide, which I feel is their absolute maximum size for pin-sharpness close up. Even at this size they are indistiguishable in sharpness and tonality - but need very careful post-processing and printing from perfect photographs. A more sensible print width for these cameras is 30 inches. Examples @ 36 inches. Note: printing is not the central concern of my post, as this has its own issues impacting image quality. Let's ignore prints in this thread.)

● There seems to be a focus on sharpness by various posters. This is irrelevant - my post is simply about comparing two mediums taken under comparable conditions with similar equipment. My calculations assume photographs taken under ideal conditions - tripod, well exposed, etc. But my argument holds even if the test photographs are hand held and have camera shake - provided both the film and digital images are equally blurred.

● In short, blurred photographs would give lower megapixel values in my calculations, but film and digital would be both lower by the same amount - so the comparable resolution of film vs digital is no different than for pin-sharp images.

● And for the sake argument, let's assume any photographs not of test charts are arresting in content, meaning and composition, with sharpness being the cherry on the cake!

● Tonal range: some dismiss cameras like the Nikon D800, saying 36 MP = bloated files with unnecessary detail. But the increased detail also increases the tonality - the D800 produces the best-quality photographs of any digital SLR, very close to low-end medium-format (various objective comparisons on the web), in large part down to its 36 MP. Current digital SLRs and colour negative film are now extremely close in tonal range. (However, colour negative film is far more forgiving than digital if over- or underexposed.)

● I understand totally the arguments about tangibility of film - though this is irrelevant to this thread.

● @ Roger Hicks. I feel you are being too dismissive, despite using the phrase "more rigorous". I have been careful to base my initial calculations on sound theory and measurements from reliable sources (tests by Kodak and DPreview using the standard resolution charts). The later calculations do use estimates, but are most certainly not "wishful thinking", and although not precise are reasonable "ball park" values. My working is clear, so if you disagree with these estimates, feel free to substitute your own values.

● Performing my own tests under rigorous conditions would be more accurate, but unless anyone finds serious flaws in the resolution data I used or in my logic, I am confident that my results are of the correct order and - more importantly - give a true comparison between film and digital of the detail in each in terms of "megapixels".
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Old 11-20-2013   #36
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8X10 digiback does not compare with 8X10 film neg. there is no theory.
except cost.
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Old 11-20-2013   #37
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I think most of your logic is flawed. Some glaring mistakes you might want to look into is the role of diffraction, and calculating the differences in diffraction over different formats and even different sensors (pixel size) and how they change data.
For instance a 6x7 film with standard lens won't become diffraction limited until after ƒ22 given a 12" wide print.
So your calculations are way off when you use focal length 50-150mm and say the multiplier is 3x that's poor science there are plenty of diffraction calculators on the internet, try one.

Also you seem to forget (or be unaware) that the megapixel count of a camera is not a measure of it's resolution, that would be it's pixel density and size.
Further to that a 12mp sensor can't resolve 12mp of detail with a Bayer sensor at best you get 6mp green, 3mp Red and 3mp Blue the output being mathematically calculated from a grid sample.
Film doesn't work like that it has RGB records but has them stacked and randomised, no digital camera has that (foveon is stacked but gridded).

I don't know where you get the figure of 80% degradation with drum scans, or the idea that film needs to be scanned. If we output to print what effect does mathematical dithering have on inkjets?

So many basic errors, mis-calculations and false assumptions in your OP that really I don't know where to start.
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Old 11-20-2013   #38
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The only relevant questions IMHO are :
For an amateur :
Does your equipment limit your abilities to take the images you want? Are you sure you already (and consistently) max out the IQ your equipment is capable of ?

For the pro:
Does you client pay for your work and do you get follow-up jobs?
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Old 11-20-2013   #39
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Not sure if I understand this post correctly...

There is a theoretical advantage in resolution of ISO100 35mm film over a 21MP full frame digital sensor. This will turn into a real world advantage only if the film camera is perfectly calibrated, shot from a tripod with a good lens stopped down, only with access to a high end drum scanner in post processing.

Wouldn´t it be easier to just chose a D800E or Sony A7R if your photography requires max resolution? (Not even talking about medium format digital...)

By the way, what happens at ISO 200?
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Old 11-20-2013   #40
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Or just choose a medium format or 4x5. How big do you print? What is the 'advantage' worth in real terms?
You obviously only need a drum scanner if you show your work digitally. What happens if I need a print? Does my inkjet or paper surface increase or decrease resolution?

Does this matter outside measurebation
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