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  1. #21

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    Quote Originally Posted by Photo Engineer View Post
    Kodak gives MTF which has a direct correlation with sharpness or resolution.

    See here, Page 18: http://www.kodak.com/global/en/profe...4016/f4016.pdf

    and here: http://www.normankoren.com/Tutorials/MTF.html for some interesting information.

    PE
    Hi,

    the Norman Koren website is not helpful for film photographers searching for realistic resolution data.
    He has some big faults in his tests. For example are his resolution conclusions based on 4000 dpi scanned films.
    But a 4000 dpi scan is not at all capable of getting all the film detail.
    We have tested some scanners, with the 4000 dpi scanners we've got only half
    of the real film resolution.
    A 140 Lp/mm resolution of Velvia 100F was reduced to only 65-70 Lp/mm with a Nikon Coolscan 9000 4000 dpi scan.

    The 140 Lp/mm visible under the microscope was only minimal reduced to 130 Lp/mm with slide projection, evaluating on the screen, with Leica Super-Colorplan P2 projection lens.

  2. #22

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    Quote Originally Posted by warrennn View Post
    I believe that the resolutions add reciprocally (like resistors in parallel), so my observed resolution should be 1/(1/70+1/140)=47 lpm, not too far from what I observed. Thanks!

    (MTF vs frequency functions are multiplied, like any transfer function.)

    Warren N
    Warren,

    first, this formular is not suitable for an exact calculation, it is more a "rule of thumb".
    Second, your value of 70 for the lens is much too small. Here you have to use the value of the aerial resolution of the lens (good primes are in the 150 - 400 Lp/mm range at f5,6 with white light). It looks like you have taken the value of lens + TMX, wich is already a system resolution, therefore you got a wrong result.

  3. #23

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    Quote Originally Posted by Athiril View Post
    The low-contrast figures are the most useful resolution, in the case of Velvia which has the highest it is 80 lp/mm iirc, about the same as the 30D and 5D II are capable of at maximum given good lenses to put in perspective if that helps.
    Fujis data is 80 Lp/mm at low contrast of only 1,6:1.
    But warrens test target has probably an higher contrast. Most printet test charts are in the 1:4 - 1:10 range, two to about three stops. By the way an object contrast, which you can find in nearly all scenes. Therefore valid for normal photography.

    Below you can find some of my test results (see my first post above) with film at this medium object contrast. Under the same test conditions our result with 24 MP FF digital was 75 Lp/mm.

    "From my own tests and experiences:

    Resolution of T-Max with my best 35mm prime lenses at lower to medium contrast (2 - 3 stops): 140 - 155 Lp/mm.
    Resolution of Velvia 100 with the same lenses: 130 - 150 Lp/mm.
    Resolution of Velvia 50 with the same lenses: 120 - 130 Lp/mm.
    Velvia 50 has a bit lower resolution than 100 because of significantly coarser grain.
    Resolution of Ektar 100: 90 - 100 Lp/mm. Fuji Reala gets 110 Lp/mm.

    With my best MF primes I got 90 - 110 Lp/mm with TMX and 85 - 100 Lp/mm with Velvia 100.
    A friend of mine got with TMX 130 Lp/mm with his 80/f4 mm Mamiya Sekor at his Mamiya 7. Marvellous glas."

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