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Author Topic: Request for help in a little R/D project: Nikon LS-9000 and Scanhancer  (Read 2122 times)

Christoph C. Feldhaim

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Dear fellow LuLaers,

I am working hybrid with MF film and a Nikon LS-9000 scanner.
Some time ago I stumbled over scanhancer (www.scanhancer.com) , a diffusor material created to better the problem with grain aliasing and other quirks conncted to scanning film.

I contacted Mr. de Goederen from scanhancer and he told me, that tests for scanhancer with the Nikon LS-9000 have not yet been very successful, as opposed to the use with other scanners (Minolta). He believes that this might be due to problems on the user side with the process.

Since the Nikon 9000 is not such a special scanner that it shouldn't be possible to significantly enhance scans from it with the diffusor we agreed he'll send me some material to do tests.

My interest in this is to enhance my own scans.

What I'd like to do is to do tests with and without the scanhancer material and with wet and dry mounting using the Kami fluid.

I'll do this with the Nikon glass holder.

My question is:
Is there anyone interested who whould be able to help with the testing by providing film negatives with images from the imatest slanted edge target, taken with a good lens to compare the various scanning methods:

1. Dry mounted, vs wet mounted
2. scanhancer / no scanhancer
3. Single Pass / MultiPass scanning
4. Super fine scan / normal scan

this would result in a comparison of 16 scans

I myself only have a Mamiya Press / Universal I will use to do "real world" tests, but I'd also like to get MTF charts (therefore imatest target) comparing the various scanning procedures.

I myself neither own imatest, nor a test chart, so I'd need someone with access to both and willing to help (by producing the negatives and analyze with imatest the scans I will produce )  to find out how much the scans can be optimized by the various methods and their combinations.

Goal is the optimum scan.

Anyone interested to help?

Cheers
~Chris


Disclaimer: I am in no way commercially involved with scanhancer, just a personal interest in scanning and getting good results.

Bart_van_der_Wolf

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I myself neither own imatest, nor a test chart, so I'd need someone with access to both and willing to help (by producing the negatives and analyze with imatest the scans I will produce )  to find out how much the scans can be optimized by the various methods and their combinations.

Goal is the optimum scan.

Anyone interested to help?

Hi Chris,

It is very easy to make a slanted edge target to be photographed oneself. Norman Koren has posted links to 2 test targets suitable for your test. They can be printed on glossy paper with an inkjet printer for the highest resolution, if you use the PDF version, open it in Photoshop at a size your paper can handle (within borders), use the native resolution of your printer (600 PPI or 720 PPI). Then assign an Adobe RGB colorspace profile (which has the correct gamma 2.2), and print it full size without scaling (100%). As long as you don't need absolute readings bust just relative ones for the different scenarios, only the contrast=20 chart (e.g. http://www.imatest.com/docs/images/small_chart_contrast_20.pdf) will suffice, although you could also add the low contrast version to satisfy your curiosity.

Only one target is needed in the center of the image. Afterall, you are not testing the lens (at various positions of the image circle), so you want to get the highest resolution on the film possible. It's the film resolution and MTF that needs to be evavuated under the different scanning conditions specified. It is very useful to have a stepwegde in the image, in order allow calibration of the results for gamma adjustments. Film has a non-linear tone curve, so a best estimate will need to be calculated should you want to compare absolute readings with other setups. When the printer profile is accurate, the printed step wegde will be close to a Kodak step wedge (20 steps).

The target shooting distance is not critical, but to have a margin for focus error and film flatness, and assuming the lens is stopped down to its optimal aperture (often 2-3 stops down from wide open), a 100x focal length is customary for film. A digital capture will also work at 25-50x FL, especially if focus is done with Live View. The hyperbolic wedges in the target are more for visual evalustion. The square with the slanted edges is what's really used for the MTF determination (together with the step wedge for gamma estimation).

I use Imatest Master, version 3.6, so I could help with evaluating the scanned results. Only a crop of the scanned relevant area is needed for evaluation.

Cheers,
Bart
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Mark D Segal

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Chris,

Apart from the PM I sent you regretting the fact that I'm not equipped for this task - I forgot to mention - LSI now sells scanner resolution targets and the instructions for how to interpret the results. This could be a handy way of testing Scanhancer, but these targets are only positive transparencies, not negatives and not necessarily the film stock you would commonly use. Regardless, perhaps worth checking on.
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Mark D Segal (formerly MarkDS)
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Christoph C. Feldhaim

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That sounds great!

Thanks a lot for the hint with the imatest targets, and I will definitely print these and do the test myself then.
I believe the 100 mm f2.8 (the non retractable one) of my Sekors will do well when stopped down a little.
Bart - I will send you the tiffs, once the testing is done.

Mark - I'll give LSI a call - I assume the targets they sell are probably near grainless - so I wonder if they could really show the advantages of the diffusor which is mostly good to reduce grain aliasing.

I'll keep you updated.
Thanks

Cheers
~Chris

Mark D Segal

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Yes, come to think of it, they are nearly grainless, so that may be a problem relative to your purposes. BUT that said, they may provide a good starting point to measure the operational resolution of your equipment BEFORE implementing any of the experiments.
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Mark D Segal (formerly MarkDS)
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