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Thread: 80mp digital better than 8x10?

  1. #311
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    Re: 80mp digital better than 8x10?

    Quote Originally Posted by Ivan J. Eberle View Post
    I've noted that long-winded theoretical Norman Koren makes such errors, BTW. He is more into formulae than most of the LuLa crowd, but nevertheless often stacks these errors in a biased way that makes digital come out on top.
    But his charts are useful for conducting informal tests. They provide a comparison strip at low frequency for the 10% or 50% MTF contrast, adjacent to the 100% MTF test strip (density controlled by sine wave) which increases in frequency. It's far less than perfect--the black is only as black as a printer can print it, for example--but nothing's better for home testing. It's a great leap ahead of the Air Force Test Chart.

    It also taught me that 10% MTF, which is how most people interpret their AF test-chart images, isn't really indicative of what will be seen as crisp sharpness.

    Rick "who does testing for fun, but evaluates prints on their own merits" Denney

  2. #312

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    Re: 80mp digital better than 8x10?

    Quote Originally Posted by rdenney View Post
    It also taught me that 10% MTF, which is how most people interpret their AF test-chart images, isn't really indicative of what will be seen as crisp sharpness.

    Rick "who does testing for fun, but evaluates prints on their own merits" Denney
    Your reply to my own last post and the ensuing discussion has been interesting and educational, but in the end here you are agreeing with my main point.... I think: One has to like the output better to switch from 8x10.

    That subjective part of the human experience simply can't be reliably reduced to preconceiving a limited number of parameters and assuming their later comparison on a scale will predict that final judgement pronouncement. This is art, not science, at the end product. You could, however, endeavor to explain what technical aspects influenced the viewers decision, after that decision was made.

    So, back to... make the best damn prints (for the purpose you intend to use the systems) you can using both systems and have a look for yourself.

  3. #313
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    Re: 80mp digital better than 8x10?

    Not sure this is allowed but I haven't got around to doing it for 4x5 yet. This is a comparison of a photograph through a microscope with a 4000dpi scan of a piece of velvia 50 shot on a Mamiya 7 80mm at f/8 (I think this must be close to the sharpest MF lens).





    I'm still mastering the use of this but it shows that film has the capability to record well more than 4000dpi of information. I will be scanning this on an 11,000 Heidleberg Tango next.

    I have also been looking at Markus' original (thanks to Markus for letting us take a look). At first glance through the microscope, the focus point doesn't match with the test area but more info once I've run it past Markus first.
    Still Developing at http://www.timparkin.co.uk and scanning at http://cheapdrumscanning.com

  4. #314

    Re: 80mp digital better than 8x10?

    what scanner did you use there? Your howtek or your Epson?

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    Re: 80mp digital better than 8x10?

    Quote Originally Posted by PaulSchneider View Post
    what scanner did you use there? Your howtek or your Epson?
    The left is the microscope and the right hand side is 4000dpi Howtek 4500. Obviously the 4000dpi Howtek scan has been uprezzed a lot to compare with the 'micrograph'.

    Tim
    Still Developing at http://www.timparkin.co.uk and scanning at http://cheapdrumscanning.com

  6. #316

    Re: 80mp digital better than 8x10?

    wow, the micrograph looks a lot better ... have you ever tried stitching a few of those images togehter?

  7. #317
    PhiloFarmer PhiloFarmer's Avatar
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    Re: 80mp digital better than 8x10?

    Ivan...I'm a great admirer of your work. I used to trek like you when I was younger...but without your patience. There's lot of technical jargon tossed around here...and each of us (I'm pretty sure..) has done their own in-the-field-and-studio comparisons. Each with our own foibles...and assumptions. There is no way, outside a weapons laboratory (where I used to work!) where such definitive, exacting tests can be run "scientifically." We have prints to show the results. So...the adage of "try-it-yourself" is quite powerful and effective.

    On the abbreviation "lp/mm" I'm assuming there was some kind of typo in your post. The abbreviation literally means "line-pairs per millimeter," NOT "lines-per-millimeter." There's a simple reason for the abbreviation: you can't tell where the white space after one line ends....WITHOUT another line! Hence the "line-pair" descriptor.

    Schneider's "35mm, MF, LF" lp/mm lens evaluations in terms of %-modulation and (diffuse) light source are largely accurate, based on my own experience. Lots of variability...to be sure...but the lp/mm descriptors basically correspond to reality.

  8. #318
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    Re: 80mp digital better than 8x10?

    Quote Originally Posted by PaulSchneider View Post
    wow, the micrograph looks a lot better ... have you ever tried stitching a few of those images togehter?
    I have only just got the device and it would take a long time to produce anything with full detail. I might have a go at a larger picture using 35mm but I don't think it will work because the sides of the view suffer heavily from saggital abberations. It would be great to have an x-y plotter device that could do this though :-)
    Still Developing at http://www.timparkin.co.uk and scanning at http://cheapdrumscanning.com

  9. #319
    Format Omnivore Brian C. Miller's Avatar
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    Re: 80mp digital better than 8x10?

    Quote Originally Posted by Asher Kelman View Post
    Well, Brian, do we have any idea what are the equivalent numbers for Apo process lenses, the ~750 to 2400mm range of Red dot Artars, Germinars and the Tessars and the like used for the printing industry's old massive plate cameras of the last century? Are there any modern higher resolution lenses, but still with such massive image circles, on the market today? Or is the Digitar quality just limited to the very modest MF fields?

    Asher
    I have absolutely no idea. You could send Schneider a question and ask them. Personally, I'd do my own tests on the Schneider lenses myself before going with the Digitar pamphlet as gospel. I'd really like to see how the Digitar lenses perform with Fuji Acros 100. I know that the center sharpness from my Wollensak lenses is really good (bicycle spokes, distant telephone wires, etc.) but I never made any kind of an actual lens test with them.

    My 8x10 enlarging lenses are Nikon, so I can't do a hands-on test.

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