Have sensors really passed the resolution of lenses? NO!

Discussion in 'Digital Photography' started by RichA, Feb 11, 2012.

  1. RichA

    RichA Guest

    I keep reading that statement, that they have.
    Does this mean that putting a good lens on a 24 megapixel camera (not
    to mention a 36mp) rather than an 16 megapixel camera will yield no
    extra resolution? Has this been anyone's experience, even with some
    marginal lenses, like Sony's 16mm pancake? I'd urge people to
    actually do some tests rather than accept it at face value.
    Reason being, there are tiny sensored cameras out there that will
    resolve a decent amount of detail with their lenses and therefore,
    scaling up those sensors to the size of larger sensors would disprove
    the idea that sensors have now out-resolved lenses.
    This could be proven quite handily by mounting a DSLR lens on a
    diminute Pentax Q with an adapter, or even using Nikon's V1 as both
    cameras, where their sensors scaled-up to say APS size for example,
    would exceed the pixel count of any (including the D800) DSLR, and it
    would be shown the lenses are capable of delivering even more detail.
     
    RichA, Feb 11, 2012
    #1
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  2. "RichA" <> wrote in message
    news:...
    > I keep reading that statement, that they have.
    > Does this mean that putting a good lens on a 24 megapixel camera (not
    > to mention a 36mp) rather than an 16 megapixel camera will yield no
    > extra resolution? Has this been anyone's experience, even with some
    > marginal lenses, like Sony's 16mm pancake? I'd urge people to
    > actually do some tests rather than accept it at face value.
    > Reason being, there are tiny sensored cameras out there that will
    > resolve a decent amount of detail with their lenses and therefore,
    > scaling up those sensors to the size of larger sensors would disprove
    > the idea that sensors have now out-resolved lenses.
    > This could be proven quite handily by mounting a DSLR lens on a
    > diminute Pentax Q with an adapter, or even using Nikon's V1 as both
    > cameras, where their sensors scaled-up to say APS size for example,
    > would exceed the pixel count of any (including the D800) DSLR, and it
    > would be shown the lenses are capable of delivering even more detail.


    The answer is, as you well, know "it depends". With some DSLR lenses, 10
    MP may well be enough to capture all they can offer when wide-open. When
    viewing a "normal size" print at "normal" distance, or looking at an image
    on a computer screen or CRT display. not pixel peeping, could you even
    tell the difference between a 16 MP and 24 MP print? I doubt it.

    To get the full resolution out of a 36 MP sensor will likely require the
    best of lenses, and some of the best of photographic techniques (such as
    tripod, best focusing, reducing mirror-slap etc. etc.)
     
    David J Taylor, Feb 11, 2012
    #2
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  3. On 02/11/2012 01:34 PM, David J Taylor wrote:
    > "RichA" <> wrote in message
    > news:...
    >> I keep reading that statement, that they have.
    >> Does this mean that putting a good lens on a 24 megapixel camera (not
    >> to mention a 36mp) rather than an 16 megapixel camera will yield no
    >> extra resolution? Has this been anyone's experience, even with some
    >> marginal lenses, like Sony's 16mm pancake? I'd urge people to
    >> actually do some tests rather than accept it at face value.
    >> Reason being, there are tiny sensored cameras out there that will
    >> resolve a decent amount of detail with their lenses and therefore,
    >> scaling up those sensors to the size of larger sensors would disprove
    >> the idea that sensors have now out-resolved lenses.
    >> This could be proven quite handily by mounting a DSLR lens on a
    >> diminute Pentax Q with an adapter, or even using Nikon's V1 as both
    >> cameras, where their sensors scaled-up to say APS size for example,
    >> would exceed the pixel count of any (including the D800) DSLR, and it
    >> would be shown the lenses are capable of delivering even more detail.

    >
    > The answer is, as you well, know "it depends". With some DSLR lenses, 10
    > MP may well be enough to capture all they can offer when wide-open. When
    > viewing a "normal size" print at "normal" distance, or looking at an
    > image on a computer screen or CRT display. not pixel peeping, could you
    > even tell the difference between a 16 MP and 24 MP print? I doubt it.
    >
    > To get the full resolution out of a 36 MP sensor will likely require the
    > best of lenses, and some of the best of photographic techniques (such as
    > tripod, best focusing, reducing mirror-slap etc. etc.)

    Consider that many consider the resolution of Kodachrome 35mm film to be
    around 100-250 mega pixels.
     
    Kenneth Scharf, Feb 11, 2012
    #3
  4. RichA

    nospam Guest

    In article <jh6kbp$p60$>, Kenneth Scharf
    <> wrote:

    > Consider that many consider the resolution of Kodachrome 35mm film to be
    > around 100-250 mega pixels.


    consider that many people are stupid. there's absolutely *nothing* that
    can support that nonsense.
     
    nospam, Feb 11, 2012
    #4
  5. RichA

    Ray Fischer Guest

    Kenneth Scharf <> wrote:
    >On 02/11/2012 01:34 PM, David J Taylor wrote:


    >> To get the full resolution out of a 36 MP sensor will likely require the
    >> best of lenses, and some of the best of photographic techniques (such as
    >> tripod, best focusing, reducing mirror-slap etc. etc.)

    >Consider that many consider the resolution of Kodachrome 35mm film to be
    >around 100-250 mega pixels.


    According to the modulation-transfer diagram for Kodachrome 25 a good
    estimate for an equivalent digital image is about 20 megapixels.

    http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf

    (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)

    --
    Ray Fischer | None are more hopelessly enslaved than those who falsely believe they are free.
    | Goethe
     
    Ray Fischer, Feb 11, 2012
    #5
  6. RichA

    Vance Guest

    On Feb 11, 10:24 am, RichA <> wrote:
    > I keep reading that statement, that they have.
    > Does this mean that putting a good lens on a 24 megapixel camera (not
    > to mention a 36mp) rather than an 16 megapixel camera will yield no
    > extra resolution?  Has this been anyone's experience, even with some
    > marginal lenses, like Sony's 16mm pancake?  I'd urge people to
    > actually do some tests rather than accept it at face value.
    > Reason being, there are tiny sensored cameras out there that will
    > resolve a decent amount of detail with their lenses and therefore,
    > scaling up those sensors to the size of larger sensors would disprove
    > the idea that sensors have now out-resolved lenses.
    > This could be proven quite handily by mounting a DSLR lens on a
    > diminute Pentax Q with an adapter, or even using Nikon's V1 as both
    > cameras, where their sensors scaled-up to say APS size for example,
    > would exceed the pixel count of any (including the D800) DSLR, and it
    > would be shown the lenses are capable of delivering even more detail.


    This is as deeply and well thought out as any post from you I have
    read. Of course, I only read your posts when I am in the mood, so you
    may have done better and I wouldn't know.

    It's an interesting question. It seems from your heading that your
    opinion is no while David Taylor's more qualitied opinion in his post
    is that it all depends, which is intuitively more appealling.
    Postings to newsgroups understandably limit how full an explanation
    can be, which is a good reason to link to outside resources. The
    conclusion reached by Luminous Landscape, using their greater
    resources and probably coming from a more knowledgeable perspective
    than most of us have, came to the conclusion the same conclusion as
    David Taylor and they definitely aren't alone.

    Quoting Luminous Landscape's conclusion in full:

    'So, do sensors outresolve lenses? It depends on the lens you use, the
    properties of the light, the aperture and the format. Small format
    sensors may have surpassed the limit, this is, in most cases they are
    lens-limited in terms of resolution. It is easier to correct
    aberrations for a smaller light circle though, so you can approach
    diffraction-limited resolutions for lower f-numbers. The signal-to-
    noise ratio, however, imposes an inflexible limit to the effective
    resolution of the whole system, mostly due to photon shot noise.

    Sensors for larger formats are approaching the diffraction limit of
    real lenses, and it is more difficult to get high levels of aberration
    suppression for them. The point is that you cannot fully exploit the
    resolution potential of high-resolution sensors with regular mass-
    produced lenses, particularly for larger formats.

    You cannot compare the limits of two different photographic systems
    looking at a print because the variables that determine the subjective
    perception come into play. Different systems can provide comparable
    results on paper under certain conditions (the circle of confusion
    reasoning explains how that is possible), but the limit of a system
    must be evaluated considering the pixel as the minimum circle of
    confusion.'

    For those who want a deeper understanding of the question, or want to
    see if the conclusion is sound, the link is:

    http://luminous-landscape.com/tutorials/resolution.shtml

    Your approach to 'proving' that sensors haven't outstripped lens
    resolution seems a weak and way to much bother. In deference to
    people who know more than I do, which seems reasonable, I have to go
    with the less catagorical answer than either 'Yes' or 'No' and say
    'Maybe', in spite of how commonly you hear 'Sensors have outstipped
    lens resolution.'

    Vance
     
    Vance, Feb 11, 2012
    #6
  7. Ray Fischer <> wrote:
    > Kenneth Scharf <> wrote:
    >>On 02/11/2012 01:34 PM, David J Taylor wrote:


    >>> To get the full resolution out of a 36 MP sensor will likely require the
    >>> best of lenses, and some of the best of photographic techniques (such as
    >>> tripod, best focusing, reducing mirror-slap etc. etc.)

    >>Consider that many consider the resolution of Kodachrome 35mm film to be
    >>around 100-250 mega pixels.


    > According to the modulation-transfer diagram for Kodachrome 25 a good
    > estimate for an equivalent digital image is about 20 megapixels.


    > http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf


    > (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)


    You want more than 2 pixels/cycle[1]. You want to seriously
    oversample[1]. You want 0% response, not 10%[2].

    (130 cycles/mm * 3 pixels/cycle * 3 (oversample))^2 * 24 * 36
    => >1 GPix. See? :)

    -Wolfgang

    [1] http://clarkvision.com/articles/sampling1/index.html
    [2] http://clarkvision.com/articles/scandetail/index.html#modulation
     
    Wolfgang Weisselberg, Feb 23, 2012
    #7
  8. "Alfred Molon" <> wrote in message
    news:...
    > Lenses do not have a resolution. There is something called modulation
    > transfer function (MTF) which tells you what the response is at a
    > certain spatial frequency. You can put a poor lens on a 36MP camera, but
    > the contrast will be low at the higher spatial frequencies.
    > --
    >
    > Alfred Molon


    Yes, and you can extend the MTF to the whole system, including any
    filtering on the sensor (e.g. anti-alias filtering), the effects on any
    processing, the MTF of the screen or printer, and the MTF of the eye, to
    predict the image on the retina.

    However, it can be convenient to take some defined point of the MTF (e.g.
    30%), or the integrated area under the MTF curve, and a single
    "resolution" equivalent measure, but as this excludes the shape of the MTF
    curve is doesn't tell the whole story.

    David
     
    David J Taylor, Feb 25, 2012
    #8
  9. RichA

    Bruce Guest

    Alfred Molon <> wrote:

    >In article <>, Alan Browne
    >says...
    >> What you posted above illustrates that "higher spatial frequency"
    >> contrast _is_ lens resolution.

    >
    >?????
    >
    >I really don't understand what you mean.




    Don't worry, Alfred. Browne doesn't understand either.
     
    Bruce, Feb 25, 2012
    #9
  10. RichA

    Joe Kotroczo Guest

    On 25/02/2012 19:55, Alan Browne wrote:
    (...)
    > If a phase sensor could be done - and very small, I guess resolutions
    > could be magnitudes higher and no lens at all would be needed.


    If you record phase as well as modulation in essence you'd have digital
    holography, no?

    --
    Illegitimi non carborundum
     
    Joe Kotroczo, Feb 25, 2012
    #10
  11. RichA

    Ray Fischer Guest

    Wolfgang Weisselberg <> wrote:
    >Ray Fischer <> wrote:
    >> Kenneth Scharf <> wrote:
    >>>On 02/11/2012 01:34 PM, David J Taylor wrote:

    >
    >>>> To get the full resolution out of a 36 MP sensor will likely require the
    >>>> best of lenses, and some of the best of photographic techniques (such as
    >>>> tripod, best focusing, reducing mirror-slap etc. etc.)
    >>>Consider that many consider the resolution of Kodachrome 35mm film to be
    >>>around 100-250 mega pixels.

    >
    >> According to the modulation-transfer diagram for Kodachrome 25 a good
    >> estimate for an equivalent digital image is about 20 megapixels.

    >
    >> http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf

    >
    >> (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)

    >
    >You want more than 2 pixels/cycle[1]. You want to seriously
    >oversample[1]. You want 0% response, not 10%[2].


    Absolute accuracy is neither the goal nor is it possible.
    This is a useful guideline.

    If you want to indulge yourself in pointless pedantry then go ahead.

    --
    Ray Fischer | None are more hopelessly enslaved than those who falsely believe they are free.
    | Goethe
     
    Ray Fischer, Feb 26, 2012
    #11
  12. RichA

    Joe Kotroczo Guest

    On 25/02/2012 20:49, Alan Browne wrote:
    > On 2012-02-25 15:33 , Joe Kotroczo wrote:
    >> On 25/02/2012 19:55, Alan Browne wrote:
    >> (...)
    >>> If a phase sensor could be done - and very small, I guess resolutions
    >>> could be magnitudes higher and no lens at all would be needed.

    >>
    >> If you record phase as well as modulation in essence you'd have digital
    >> holography, no?

    >
    > You certainly have the information to focus at any distance and resolve
    > for any desired DOF. Not sure about holography.


    Plenoptic camera maybe?

    > The article in wikipedia is a good start, and it it:
    >
    >
    > [1] A hologram represents a recording of information regarding the light
    > that came from the original scene as scattered in a range of directions
    > rather than from only one direction, as in a photograph. This allows the
    > scene to be viewed from a range of different angles, as if it were still
    > present.
    >
    > [3] A holographic recording requires a second light beam (the reference
    > beam) to be directed onto the recording medium.
    >
    > and much more, of course.


    Yes, but that's for analog holograms, with a physical recording medium
    such as photopolymers or photorefractives.

    If you look at <http://en.wikipedia.org/wiki/Digital_holography> you'll
    find "The phase-shifting digital holography process entails capturing
    multiple interferograms that each indicate the optical phase
    relationships between light returned from all sampled points on the
    illuminated surface and a controlled reference beam of light that is
    collinear to the object beam"

    Not that I truly understand any of it... ;-)

    --
    Illegitimi non carborundum
     
    Joe Kotroczo, Feb 26, 2012
    #12
  13. RichA

    Martin Brown Guest

    On 26/02/2012 18:38, Alfred Molon wrote:
    > In article<>, Alan Browne
    > says...
    >> What set me off was when you said "lenses do not have a resolution".
    >> (They do).

    >
    > Lenses have an MTF, but for sure not a resolution in megapixel.


    For a specified zone of illumination they do. The choice of matching CCD
    pixel size in microns to a given optical assembly on a telescope is
    something astronomers think about much more than photographers.

    The standard Rayleigh criterion for the angular resolution of a lens of
    finite aperture is close enough for most purposes as 1.22*lambda/D
    (radians).

    Multiply that by the distance to the CCD and you have a bound based on
    the sampling criterion that allows you to compute the pixel size and
    resolution the lens can support. It is traditional to oversample
    slightly by 1.5-2x to avoid jaggies in the raw data.

    Advanced tricks can get you a factor of 3 better than classical
    resolution performance in a very restricted set of circumstances.

    --
    Regards,
    Martin Brown
     
    Martin Brown, Feb 26, 2012
    #13
  14. RichA

    Martin Brown Guest

    On 26/02/2012 22:19, Alfred Molon wrote:
    > In article<g3x2r.18667$>, Martin Brown says...
    >> On 26/02/2012 18:38, Alfred Molon wrote:
    >>> In article<>, Alan Browne
    >>> says...
    >>>> What set me off was when you said "lenses do not have a resolution".
    >>>> (They do).
    >>>
    >>> Lenses have an MTF, but for sure not a resolution in megapixel.

    >>
    >> For a specified zone of illumination they do. The choice of matching CCD
    >> pixel size in microns to a given optical assembly on a telescope is
    >> something astronomers think about much more than photographers.
    >>
    >> The standard Rayleigh criterion for the angular resolution of a lens of
    >> finite aperture is close enough for most purposes as 1.22*lambda/D
    >> (radians).
    >>
    >> Multiply that by the distance to the CCD and you have a bound based on
    >> the sampling criterion that allows you to compute the pixel size and
    >> resolution the lens can support. It is traditional to oversample
    >> slightly by 1.5-2x to avoid jaggies in the raw data.
    >>
    >> Advanced tricks can get you a factor of 3 better than classical
    >> resolution performance in a very restricted set of circumstances.

    >
    > Once again, lenses have a response curve. The higher the spatial
    > frequency, the lower the contrast. But you can't say that a lens will
    > only let pass through 80 lp/mm and not 120lp/mm, although at a certain
    > spatial frequency the MTF will be too low to be usable.


    Actually you *can* to a very good approximation. Once the Rayleigh
    criterion is exceeded you cannot sensibly distinguish two adjacent dots.

    If you haven't sampled a spatial frequency in the image then it is lost.
    The highest spatial frequency you can measure is determined by the ratio
    of the wavelength of light to the diameter of the lens. This is all
    classical wave optics and well understood physics.

    > By the way, the formula you are quoting has nothing to do with the
    > quality of the lens (and the ability to resolve detail depends on the
    > lens quality). The only parameters are the wavelength of light and the
    > diameter of the aperture.


    That formula assumes diffraction limited optics typical of telescopes
    but a condition that is seldom met in consumer level photographic lenses
    at apertures wider than f5.6 (though there are exceptions).

    The Rayleigh criterion assumes near perfect lens performance with
    overall rms errors in the optical surfaces of lambda/4 or less.

    --
    Regards,
    Martin Brown
     
    Martin Brown, Feb 26, 2012
    #14
  15. Alan Browne <> wrote:

    > There is also the "Kodak equation" which used say something like the
    > resolution of the system is that of the lens and that of the film
    > combined - it's not simply the worst of the two. I can't find the
    > equation offhand, it may have been: sysres = 1/(1/filmres+1/lensres)


    Isn't it
    MTF_{system} = MTF_{lens} * MTF_{sensor}
    ?

    That would make sense --- MTF is 0--1, the whole system is weaker
    than all (imperfect) components, the weakest component limits the
    system most (and increasing the better component(s) only results
    in slight improvements overall), ...

    -Wolfgang
     
    Wolfgang Weisselberg, Mar 2, 2012
    #15
  16. Ray Fischer <> wrote:
    > Wolfgang Weisselberg <> wrote:
    >>Ray Fischer <> wrote:
    >>> Kenneth Scharf <> wrote:
    >>>>On 02/11/2012 01:34 PM, David J Taylor wrote:


    >>>>> To get the full resolution out of a 36 MP sensor will likely require the
    >>>>> best of lenses, and some of the best of photographic techniques (such as
    >>>>> tripod, best focusing, reducing mirror-slap etc. etc.)
    >>>>Consider that many consider the resolution of Kodachrome 35mm film to be
    >>>>around 100-250 mega pixels.


    >>> According to the modulation-transfer diagram for Kodachrome 25 a good
    >>> estimate for an equivalent digital image is about 20 megapixels.


    >>> http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf


    >>> (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)


    >>You want more than 2 pixels/cycle[1]. You want to seriously
    >>oversample[1]. You want 0% response, not 10%[2].


    > Absolute accuracy is neither the goal nor is it possible.
    > This is a useful guideline.


    > If you want to indulge yourself in pointless pedantry then go ahead.


    Ah, that's how you react to facts. Should have known.

    -Wolfgang
     
    Wolfgang Weisselberg, Mar 3, 2012
    #16
  17. RichA

    Ray Fischer Guest

    Wolfgang Weisselberg <> wrote:
    >Ray Fischer <> wrote:
    >> Wolfgang Weisselberg <> wrote:
    >>>Ray Fischer <> wrote:
    >>>> Kenneth Scharf <> wrote:
    >>>>>On 02/11/2012 01:34 PM, David J Taylor wrote:

    >
    >>>>>> To get the full resolution out of a 36 MP sensor will likely require the
    >>>>>> best of lenses, and some of the best of photographic techniques (such as
    >>>>>> tripod, best focusing, reducing mirror-slap etc. etc.)
    >>>>>Consider that many consider the resolution of Kodachrome 35mm film to be
    >>>>>around 100-250 mega pixels.

    >
    >>>> According to the modulation-transfer diagram for Kodachrome 25 a good
    >>>> estimate for an equivalent digital image is about 20 megapixels.

    >
    >>>> http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf

    >
    >>>> (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)

    >
    >>>You want more than 2 pixels/cycle[1]. You want to seriously
    >>>oversample[1]. You want 0% response, not 10%[2].

    >
    >> Absolute accuracy is neither the goal nor is it possible.
    >> This is a useful guideline.

    >
    >> If you want to indulge yourself in pointless pedantry then go ahead.

    >
    >Ah, that's how you react to facts.


    Ah, that's how you lie. By claiming that you have "facts".

    --
    Ray Fischer | None are more hopelessly enslaved than those who falsely believe they are free.
    | Goethe
     
    Ray Fischer, Mar 3, 2012
    #17
  18. "Wolfgang Weisselberg" <> wrote in message
    news:...
    > Alan Browne <> wrote:
    >
    >> There is also the "Kodak equation" which used say something like the
    >> resolution of the system is that of the lens and that of the film
    >> combined - it's not simply the worst of the two. I can't find the
    >> equation offhand, it may have been: sysres = 1/(1/filmres+1/lensres)

    >
    > Isn't it
    > MTF_{system} = MTF_{lens} * MTF_{sensor}
    > ?
    >
    > That would make sense --- MTF is 0--1, the whole system is weaker
    > than all (imperfect) components, the weakest component limits the
    > system most (and increasing the better component(s) only results
    > in slight improvements overall), ...
    >
    > -Wolfgang


    Wolfgang, you also need to include the atmosphere, processing and display
    to get the system MTF, but in terms of lens and sensor, you are correct.

    Likely, if you convert MTF into a single figure (e.g. by integrating the
    area under the MTF curve), the "Kodak equation" is equivalent.

    Cheers,
    David
     
    David J Taylor, Mar 3, 2012
    #18
  19. Ray Fischer <> wrote:
    > Wolfgang Weisselberg <> wrote:
    >>Ray Fischer <> wrote:
    >>> Wolfgang Weisselberg <> wrote:
    >>>>Ray Fischer <> wrote:
    >>>>> Kenneth Scharf <> wrote:
    >>>>>>On 02/11/2012 01:34 PM, David J Taylor wrote:


    >>>>>>> To get the full resolution out of a 36 MP sensor will likely require the
    >>>>>>> best of lenses, and some of the best of photographic techniques (such as
    >>>>>>> tripod, best focusing, reducing mirror-slap etc. etc.)
    >>>>>>Consider that many consider the resolution of Kodachrome 35mm film to be
    >>>>>>around 100-250 mega pixels.


    >>>>> According to the modulation-transfer diagram for Kodachrome 25 a good
    >>>>> estimate for an equivalent digital image is about 20 megapixels.


    >>>>> http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf


    >>>>> (70 cycles/mm * 2 pixels/cycle * 35mm) * (70 * 2 * 25)


    >>>>You want more than 2 pixels/cycle[1]. You want to seriously
    >>>>oversample[1]. You want 0% response, not 10%[2].


    >>> Absolute accuracy is neither the goal nor is it possible.
    >>> This is a useful guideline.


    >>> If you want to indulge yourself in pointless pedantry then go ahead.


    >>Ah, that's how you react to facts.


    > Ah, that's how you lie. By claiming that you have "facts".


    You didn't see/remember the URLs? Could be a brain tumor.
    Could be just you.

    -Wolfgang
     
    Wolfgang Weisselberg, Mar 14, 2012
    #19
  20. David J Taylor <> wrote:
    > "Wolfgang Weisselberg" <> wrote in message
    >> Alan Browne <> wrote:


    >>> There is also the "Kodak equation" which used say something like the
    >>> resolution of the system is that of the lens and that of the film
    >>> combined - it's not simply the worst of the two. I can't find the
    >>> equation offhand, it may have been: sysres = 1/(1/filmres+1/lensres)


    >> Isn't it
    >> MTF_{system} = MTF_{lens} * MTF_{sensor}
    >> ?


    >> That would make sense --- MTF is 0--1, the whole system is weaker
    >> than all (imperfect) components, the weakest component limits the
    >> system most (and increasing the better component(s) only results
    >> in slight improvements overall), ...


    > Wolfgang, you also need to include the atmosphere, processing and display
    > to get the system MTF, but in terms of lens and sensor, you are correct.


    Depends on how the 'system' is defined, :) but yes, you're right.
    If you include atmosphere again and the human eye, that is.

    > Likely, if you convert MTF into a single figure (e.g. by integrating the
    > area under the MTF curve), the "Kodak equation" is equivalent.


    However, you need something else, you need to factor in how the
    eye perceives the sharpness (which depends on print size and
    viewing distance).

    -Wolfgang
     
    Wolfgang Weisselberg, Mar 14, 2012
    #20
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    RichA
    Mar 23, 2012
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