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  1. #21
    RalphLambrecht's Avatar
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    Quote Originally Posted by kauffman v36 View Post
    ...im wondering if technical pan + some crazy leica or zeiss lens and a schneider APO enlarging lens would give noticably higher ln/mm
    I think the question goes into the wrong direction. How would it help your photography to know that your lenses perform best with a high-contrast micro film? The answer is clear, they do, but these films are not ideal for practical photography, so why test with them. To evaluate lenses, and more importantly, how any difference impacts our photography, they should be tested with the films we use. Also, resolution measured in lp/mm (line pairs per mm, not ln/mm) is a poor measure of lens performance anyway. Contrast and sharpness being more important than resolution, only an MTF will tell.

    Fully agree with phenix, by the way.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  2. #22
    Athiril's Avatar
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    Arent most good films around the 60 lp/mm at 1.6:1 contrast ratio? That is what I call useful resolution, ie: across the texture of an object, the 1000:1 figure is for shooting sharp-edged silhouette backlit tree branches against a white sky :P

    There are of course much higher resolution films... Rollei ATP, Adox CMS 20. etc


    Reasonably large prints from my 30D look critically good to me, 35mm film is capable of more than my 30D, so therefore would do better and satisfy critical print demands.

    Quote Originally Posted by kauffman v36 View Post
    alan, you bring up something i was going to ask. thoeretically, what would be the combination to give the highest resolution using a 35mm system.

    im wondering if technical pan + some crazy leica or zeiss lens and a schneider APO enlarging lens would give noticably higher ln/mm

    CMS 20 + The Polar/Samyang 85/1.4 would be a great test if ultimate sharpness makes you happy.

  3. #23
    RalphLambrecht's Avatar
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    Quote Originally Posted by Athiril View Post
    Arent most good films around the 60 lp/mm at 1.6:1 contrast ratio? That is what I call useful resolution, ie: across the texture of an object, the 1000:1 figure is for shooting sharp-edged silhouette backlit tree branches against a white sky :P...
    Kodak lists Tmax100 at 63 lp/mm and Tmax400 at 50 lp/mm at 1.6:1. That's probably as unrealistic as listing 200 lp/mm at 1,000:1. Nevertheless, it shows that film and paper limit the system performance significantly. I'd like to see the figures for 160:1, which is an average scene contrast of roughly 7 stops. I assume it's around 125 lp/mm.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  4. #24
    Athiril's Avatar
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    160:1 contrast resolution would be how sharp one edge is next to edge that is 7 and 1/3 stops difference, not the resolution of a scene that is 7 and 1/3 stops wide. You're extremely unlikely to find any 7 and 1/3 stop edges in any kind of normal exterior scene, the transitions are much lower than that, and most transitions are not hard-edged, you wont get that on the hard edge between direct sun and shadow either, you'd have to set up a controlled situation where there is no ambient bounce back into the shadows.

    The texture of bark or someone's skin etc, is not going to be 7 and 1/3 stops of variance over those surfaces as a whole, let along as the texture/transition from each "line" of the surface, surface detail is going to be in the 1.6:1 vicinity.
    Last edited by Athiril; 05-17-2010 at 05:34 AM. Click to view previous post history.

  5. #25
    RalphLambrecht's Avatar
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    Quote Originally Posted by Athiril View Post
    160:1 contrast resolution would be how sharp one edge is next to edge that is 7 and 1/3 stops difference, not the resolution of a scene that is 7 and 1/3 stops wide. You're extremely unlikely to find any 7 and 1/3 stop edges in any kind of normal exterior scene, the transitions are much lower than that, and most transitions are not hard-edged, you wont get that on the hard edge between direct sun and shadow either, you'd have to set up a controlled situation where there is no ambient bounce back into the shadows.

    The texture of bark or someone's skin etc, is not going to be 7 and 1/3 stops of variance over those surfaces as a whole, let along as the texture/transition from each "line" of the surface, surface detail is going to be in the 1.6:1 vicinity.
    Good point. I have some RIT resolution targets with varying contrast (three different setting, I believe). They clearly show the influence of subject contrast on resolution measurements. I also measured my USAF 1951 targets, which I bought from Edmund's Scientific. They have a density range (black printing vs white paper) of over 100:1.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  6. #26
    ic-racer's Avatar
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    Here are two examples. An Olympus 50mm 1.4 SLR lens vs a Leica 50mm 1.4 rangefinder lens.

    Error bars represent "similar lenses in class."

    Y-axis is contrast at a given 50 line pairs per millimeter. So these read a little more like a contemporary MTF chart.

    I think this info is interesting to read and also may be of some benefit to the next generation of 35mm film users who need to sort through all the left-over cameras from the last generation.


    Last edited by ic-racer; 05-17-2010 at 04:49 PM. Click to view previous post history.

  7. #27
    RalphLambrecht's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    Good point. I have some RIT resolution targets with varying contrast (three different setting, I believe). They clearly show the influence of subject contrast on resolution measurements. I also measured my USAF 1951 targets, which I bought from Edmund's Scientific. They have a density range (black printing vs white paper) of over 100:1.
    I checked my files. The RIT targets come in three different contrasts:

    32:1, 6.3:1, and 1.6:1
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  8. #28
    Rol_Lei Nut's Avatar
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    Quote Originally Posted by ic-racer View Post
    Here are two examples. An Olympus 50mm 1.4 SLR lens vs a Leica 50mm 1.4 rangefinder lens.
    Those seem to be especially thorough and well-done tests.
    I don't have either lens, but the results could seem to fit their reputations (Olympus over-corrected for outer edge?)

    Where can I find more?

    Best regards
    M6, SL, SL2, R5, P6x7, SL3003, SL35-E, F, F2, FM, FE-2, Varex IIa

  9. #29
    Athiril's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    I checked my files. The RIT targets come in three different contrasts:

    32:1, 6.3:1, and 1.6:1
    It'd be interesting to see lens performance @ 1.6:1, rather than on typical charts, as well as interesting to see how the other low-contrast areas perform that you have there (6.3:1)

  10. #30

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    Lots of good points here. Need to be careful of terminology though. Any lens is always diffraction limited at its maximum aperture, since the Airy disk size is only a function of the aperture diameter. The best performance may be found at smaller than maximum apertures due to better optical correction by stopping down.

    To check the intrinsic resolution of a lens I used to use Kodak High Resolution Glass Plates (HRGP) that used a very fine emulsion capable of 2000 L/mm. For lithography applications we were interested in high resolution at the best contrast we could get since the HRGP plates were very high contrast emulsions. There are no equivalent modern emulsions to HRGP that I know of. For modern photographic purposes it is clearly more important to consider the film/lens performance as a unit as suggested by Ralph.

    Nate Potter, Austin TX.

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