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Thread: What are the film scanner options in 2017?

  1. #31

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    Re: What are the film scanner options in 2017?

    Quote Originally Posted by Pere Casals View Post
    Why not ?

    Just scan a USAF 1951 resolution target slide and post the scan.

    https://en.wikipedia.org/wiki/1951_U...ion_test_chart

    If group 6 element 2 bars are seen then your system is outresolving LF lenses, so enough for LF sheets. If you see Group 7 elements then you have a first class system...


    Here you have the result from an X5 (Not a drum, but close, This is scanning 35mm):





    You can compare to that.

    Other practical tests can be done with an IT8 slide target, for density, etc, Also you can measure stray light.

    https://www.flickr.com/photos/timpar...125592977@N05/



    IMHO numeric tests do not explain all but a lot is explained...

    Fair enough. The last AF test target scans I made on several D4000s and a Tango resulted in a resolution figure a little better than about 4300 dpi. I forget the formula for translating between the Air Force target and DPI. Anyone have that?

    I'll do a D800E scan of my AF target this weekend and post the results.

    I'll also scan an IT8 target. I'm not sure how much that would satisfy the question. It's a reference target and using its calibration file will certainly produce a color reference frame for a particular machine, but I don't think individual machines can be compared to each other by looking at their images of different IT8 targets. Someone set me straight if my logic is off here.

    FWIW, producing scanner ICC profiles from an IT8 target never really helped me with any scanner I've used. It always resulted in crushed blacks, despite the Don Hutchinson "trick" of covering the darkest patches on the target with metal foil tape to make them absolutely opaque. Scanning without a scanner profile and subsequent color correcting on a calibrated monitor, using the original transparency transilluminated by daylight/calibrated light source, or by comparing to known reference images on screen was always much better.

  2. #32

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    Re: What are the film scanner options in 2017?

    Quote Originally Posted by Rich14 View Post
    Fair enough. the formula for translating between the Air Force target and DPI. Anyone have that?
    Here http://www.filmscanner.info/en/Aufloesung.html you have these tables, no conversion needed, bottom table says dpi from Group and Element:

    Click image for larger version. 

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    This is the common (I'd say controversial) way to tell "scanner optical dpi" an scanner resolves. Here we can have some controversy because we can say we need 2 points to resolve a line or we can say we need way less than 2 points, depending on the modulation transfer % we consider.




    Quote Originally Posted by Rich14 View Post
    I'll do a D800E scan of my AF target this weekend and post the results.

    I'll also scan an IT8 target. I'm not sure how much that would satisfy the question. It's a reference target and using its calibration file will certainly produce a color reference frame for a particular machine, but I don't think individual machines can be compared to each other by looking at their images of different IT8 targets. Someone set me straight if my logic is off here.

    FWIW, producing scanner ICC profiles from an IT8 target never really helped me with any scanner I've used. It always resulted in crushed blacks, despite the Don Hutchinson "trick" of covering the darkest patches on the target with metal foil tape to make them absolutely opaque. Scanning without a scanner profile and subsequent color correcting on a calibrated monitor, using the original transparency transilluminated by daylight/calibrated light source, or by comparing to known reference images on screen was always much better.
    One important thing is measuring the amount of stray light, this is a transparent slide with a little black patch, compared with a totally black slide.

    I about color... scanner and DSLR sensors may have different spectral responses, but difference can be narrow after using a conversion LUT.

    I'd like to see your tests, thanks in advance.

  3. #33

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    Re: What are the film scanner options in 2017?

    Here is the detail of the USAF resolution chart (sorry for the dirt in the scan - I didn't clean the film):

    Click image for larger version. 

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    The full size, original file is here for viewing or downloading.

    https://www.dropbox.com/s/wu9354fcu1k3lnp/USAF.jpg?dl=0

    This is a jpeg processed from the RAW NEF file in ACR and Photoshop. No adjustments or sharpening of any kind. The D800E's white balance was probably set to that of the LED tablet on which the target was scanned.

    I can read to Group 5, element 6, maybe a partial read of element 7. That puts the resolution in the neighborhood of 5000 ppi. Since the camera is focused at 1:1 and the pixel density is 4900 across the 1 inch dimension, resolution can, of course be no higher than that. Suffice to say the camera and lens are are delivering well above 4000 ppi, and in the neighborhood of a 5000 ppi "scan." I have never seen any usable image data from commercially available film stocks above about 3500 - 4000 ppi no matter what users of machines with so-called scan resolutions of 8000 ppi or 11,000 ppi claim. So the D800E/Micro Nikkor f/2.8 AF D (shooting aperture 3 stops down from wide open) is pulling everything that can be seen on film at this reproduction ratio as far as resolution in concerned. The shooting aperture was set 3 stops down from wide open. That's usually f/8. At the 1:1 reproduction ratio, that is actually f/13, which the camera reported. I call it f/8 for simplicity as that's where I set the lens for all reproduction ratios as that's where it performs best, whatever the f/ratio truly is mathematically.

    Here's a Kodak IT8 target scan.

    Click image for larger version. 

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    And here's the link to the full-sized jpeg for viewing or downloading.

    https://www.dropbox.com/s/rbsuh2w0krkjyth/IT8.jpg?dl=0

    This is a scan of the full 4x5 transparency as one shot with the D800E. I usually scan 4x5s in four slightly overlapping quadrants and stitch them together via ACR and Photoshop. I did scan the IT6 target that way, but the resulting files gave Photoshop's stitching algorithm fits in putting the four pieces together. This is the first time I have run into this kind of problem. It really surprised me, but the problem became obvious after a few retries at large and smaller scan sizes, trying to change the overlap which is what I first thought was the issue. It has nothing at all to do with the D800E's capability for scanning.

    First, Photoshop completely removed the gray border around the central area of color patches, cropping the image to just the color patch region.

    Second it assembled the four images out of order.

    My take is that the algorithm saw the uniform border as being superfluous overscan outside the desired "image." Then it couldn't make heads nor tails out of the four quadrants as there is no unifying "image theme" like there is in images of the "natural world." I assume some other kind of test chart might have fared better, but the semi-random color patch data is not something the algorithm is made for. I have never experienced difficulty stitching the quadrants of a 4x5 image of the natural world. I doubt I ever will.

    If anyone wants to see the individual quadrants, I'll give links to them, but they give no more information than the image I've posted as far as the use of the IT8.

    The posted image is about 1250 ppi. If I could have correctly assembled the quadrants, the resulting image would have been 2500 ppi. I've never had occasion to scan a 4x5 at higher resolution. There is no additional resolution in a 4x5 image above about 2000 ppi. If super large prints are needed (above about 50 inches in the short dimension) upscaling a 2000 ppi scan gives identical results to scanning a 4x5 at 4000 ppi (which takes a long time on any drum scanner).

    The D800E's white balance was set to that of the LED tablet. I adjusted camera exposure until I got flashing "blinkies" in the white patches. No adjustments of any kind have been made in ACR or Photoshop. No sharpening. The NEF file was simply sampled from 16 bit to 8 bit and saved as a JPEG.

    When I get the test image in the mail I'll post my scan.

    Please let me know if there are any problems with the links. I will leave the files up for the foreseeable future.

    Response to this will be interesting.

    Rich

  4. #34

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    Re: What are the film scanner options in 2017?

    Quote Originally Posted by Rich14 View Post
    I can read to Group 5, element 6,

    You have to read the table in the other direction... 5/6 is the column that has the "5" header in the top, so it is around 2900 dpi (instead 5000), not bad anyway !!!!

    Thanks for posting this interesting test.


    The IT8 test shows an amount of stray light, as lighter colors (pastel) have more white. This can be solved in part in post process, calibration wont solve it because different scenes will deliver diferent amounts of stray light.

    My interpretation of the test is that it is a viable system for LF, in special for BW, the single issue, IMHO, is that one has to remove the stray light level in PS, and perhaps it won't work very vell for the case of high densities present in some slides, and in few negatives.

  5. #35

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    Re: What are the film scanner options in 2017?

    Sorry for misreading the chart. The Lasersoft target is labeled differently. I should have realized there is no way the lens and sensor working together could give a result of close to 5000 ppi since the sensor's pixel density is itself 4900 photo sites per inch. Theoretically the system should produce about half of that figure. But resolution is not an issue since it could be increased simply by using a higher magnification ratio. I can't do that with the Micro Nikkor 105 without adding an extension tube. Easy enough. Then there would be a stitching step for 35mm scans as well as for larger formats. Also trivial.

    As it is, the 1:1 set up is sufficient for all but gargantuan prints from the format. Using a Pentax 645Z, Hasselblad X1D or Fujifilm GFX all of which contain the 50mp Sony sensor of equal or better performance than their 36mp D800 sensor would remedy that in a single step.

    I'm not sure what you're referring to as "stray light" in the shot of the IT8 target. The only light entering the camera is that passing through the transparency which is completely masked all around on the LED light table. The scan was done in a relatively dim room. The image does look lighter in the highlights (less contrast) than the target looks visually. But that's the point of using a calibrated target to generate an (ICC) profile of an image system. We expect nonlinearity. That's what the profile corrects (mostly).

    Do you mean that the image is being "self-contaminated" by light because the camera sees the entire area of the transparency at once, while a drum scanner sees only an individual scan spot at a time?

    The real test is going to be comparing a (corrected) scan from my D800E against that done on a Tango by someone else.

    Rich

  6. #36

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    Re: What are the film scanner options in 2017?

    Quote Originally Posted by Rich14 View Post

    Do you mean that the image is being "self-contaminated" by light because the camera sees the entire area of the transparency at once, while a drum scanner sees only an individual scan spot at a time?

    Rich

    Yes, this is. A lens self-generates parasite (stray) light. This depends a lot on the number of optical groups and on the coating performance.

    The amount of parasite light also depends on the particular negative (or slide) you scan. A very "transparent" slide will trow a lot of light to the lens, and a little share of it will be dispersed. If you have also deep shadows in the slide this contamination will make a difference, and you'll need to manage that in the digital processing.


    A flatbed only illuminates a row at a time, so there is less chance that a lot of stray light arrives to the sensor, also the Micro 105 is a good lens generating limited amounts of stray light, but as you see a big area this worsens the thing in front of a flatbed.

    ...and a drum is near free from stray light, as a single point is illuminated and read.


    You can measure the stray light amount by placing an small opaque patch in the middle of the negative, that reading in the opaque patch is the amount of the stray light, you can compare with a reading made with illumination closed.

    Of course to measure that you have to take completely raw images, without any in-camera correction.

  7. #37

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    Re: What are the film scanner options in 2017?

    Understood. Yes that's an issue. Both theoretical and practical.

    But in my completely unscientific testing, the path through the camera's exposure compensation, inherent in-camera RAW settings and ACR/Photoshop "post" processing produce results equal to or better than my own D4000 or Tango scans on screen or printed on an Epson 7890.

    I originally tried using some old 150mm and 300mm repro process lenses. As well as my 50mm f/2.8 EL Nikkors (both original and "newer" designs). I expected the process lenses to give excellent 1:1 performance. But nothing works as well as the Micro Nikkor. I believe a big part of the problem with the others was flare in the extension tube and bellows setups. I may be able to improve on that but the Micro Nikkor is just so easy to use.

    I imagine there are better lenses for this purpose, but this one is hard to beat.

  8. #38
    Peter De Smidt's Avatar
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    Re: What are the film scanner options in 2017?

    A 75mm Rodagon D, the 1x version, works very well for this.
    "Why can't we all just get along?" President Dale, Mars Attacks

  9. #39

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    Re: What are the film scanner options in 2017?

    Quote Originally Posted by Rich14 View Post
    But in my completely unscientific testing, the path through the camera's exposure compensation, inherent in-camera RAW settings and ACR/Photoshop "post" processing produce results equal to or better than my own D4000 or Tango scans on screen or printed on an Epson 7890.
    I agree a lot that accurate post processing may be very important, IMHO sometimes it is more important than the pure scanner performance.

    Sometimes drums deliver better results simply beacuse a good operator is on-board.

    Real shooting conditions are field conditions, not lab conditions, this means that the "on film" actually resolved lp/mm are far from lens maker specifications: those are ultimate performance in ideal conditions, with perfect alignment, perfect focus, optimal aperture, no vibration and a contrasty subject.

    TMX, a sharp film, resolves 200 lp/mm for 1:1000 (micro)contrast, but for common contrast you can find in textures it may resolve just 50 lp/mm at extintion. What I'm suggesting is that at the end most times a very good scanner will make not a great difference, simply because the inferior machine is able to extract most of on film information yet.

    IMHO there are some shots that deserve a good scanning machine, but a number of factors are required: A technically perfect shot, with a very sharp lens, at optimal aperture, with a sharp film, and lots of microcontrast, and a big print.

    If it is not the case the most important part is edition, using the rĄght sharpening and the right PS downsizing algorithms. A perfectly sharp image can look bad simply because web browser resizing.

    This is what I personally concluded... but I'm still a learner, and sharpness is a really complex concept, more complex than it looks, IMHO.

    For MF and 35mm a very good scanner may also help to depict film grain more naturally... but this is also a complex thing

    Pere

  10. #40
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    Re: What are the film scanner options in 2017?

    Rodagon D 75mm f/4 at 1x magnification with a D600. Raw developed with Capture One with no sharpening. Image cropped at 100% view in Photoshop.

    "Why can't we all just get along?" President Dale, Mars Attacks

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