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Thread: Compact drumscanner

  1. #11

    Join Date
    Oct 2010
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    Oberkochen
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    141

    Re: Compact drumscanner

    Don't get lost in technical data too much, focus on condition, software and availabilty instead. The Tango has a small footprint (66x64cm) but is very heavy - 250kg which also indicates the build quality and engineering.

    The drum-mount is machined stainless steel, the drums are balanced, the motor is of high-quality - it runs much smoother than a Howtek and many other small drum scanners.

    I have recently acquired a Tango, it replaces my Eversmart and Howtek D4000. The dynamic range and resolution is not too different, the Tango propably has the edge - but my test is based on an excellent-condition Howtek-scan with agressive tone curves applied. My own Howtek is not capable of producing similar results, especially because of a "jitter"artifact.
    The aperture size is also an overrated criteria, it doesn't exactly relate to resolution (e.g. 10mikron = 2540ppi) but mostly affects the rendering of grain - even on high-res negatives I set the aperture beyond 10mikron. I will make a post on my blog showing a comparison: drumscan.blogspot.de

  2. #12

    Join Date
    Oct 2007
    Posts
    601

    Re: Compact drumscanner

    Right... We went through this before. Lenny doesn't even us the 3 micron setting for anything. It's pretty much for leica users who are using advanced technical pan or some type of high resolution surveillance film. The grain structure for LF films is big for those little apertures... All you get is a bunch of color noise from "grain aliasing". IRL the tango has a small enough aperture for any large format use.

    The premier is also limited to a D-max of 3.88.

  3. #13

    Join Date
    Oct 2007
    Posts
    601

    Re: Compact drumscanner

    The tango does require sturdy floors... Cement is ideal. You can actually put it on a carpeted floor as well, you only need to find a 1" thick sheet of aluminium to put it on

  4. #14

    Join Date
    Oct 2005
    Location
    Santa Cruz, CA
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    2,094

    Re: Compact drumscanner

    Quote Originally Posted by 8x10 user View Post
    The premier is also limited to a D-max of 3.88.
    I wouldn't use this to compare anything. In their own comparison, they used 3.4 vs the Tango at 3.0. Imacon said 4.6, which is beyond all film, and is a ridiculous assertion, based on theoretical numbers vs real ones. Aztek's rating was 2.7 for Imacon.

    I would simply say that the Premier has the capacity to dig deeply into very dark area of the film. I'm sure the Tango can as well. Anything with a PMT is going to beat the CCD scanners in this regard as the PMT are very sensitive. Trying to make sense out of any of the comparisons is a futile exercise, I think. There is no independent and verified set of numbers to compare with.

    If one drum is better than another it is likely a very small amount.

    Lenny
    EigerStudios
    Museum Quality Drum Scanning and Printing

  5. #15

    Join Date
    Sep 2003
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    South Carolina
    Posts
    5,506

    Re: Compact drumscanner

    Quote Originally Posted by georgl View Post
    The aperture size is also an overrated criteria, it doesn't exactly relate to resolution (e.g. 10mikron = 2540ppi) but mostly affects the rendering of grain - even on high-res negatives I set the aperture beyond 10mikron. I will make a post on my blog showing a comparison: drumscan.blogspot.de

    The issue is discussed in Tim Vitale’s article, “Film Grain, Resolution and Fundamental Film Particles”

    Vitale writes,

    “Art of Drum Scanning -- No Film Grain with Higher Digital Image Resolution Often, a drum scanner operator will choose a pixel pitch (ppi) that is much smaller than the aperture. An example: the operator selects a 12 um aperture (113 um2 round) because it is known to eliminated film grain for the film being scanned, and then scans the image at 4000 ppi pixel pitch, which has an equivalent pixel size of 6.3 um, smaller than the aperture size.
    The aperture size is 12 um, but the pixel size is 6.3 um; all detail between 6.3 um and 12 um is lost, but the image file has a large number of pixels based on the 4000 ppi pixel pitch. The PMT sees uniformly mixed light through the 12 um aperture, from the region of the film corresponding to the pixel pitch selected (4000 ppi). The light is measured and converted to digital values, and then applied to each of the 6.3 um pixels (each pixel has 40 um2 area).
    The large aperture size (12 um) corresponds to a resolution of 2117 ppi, but the pixel pitch is 4000 ppi. Each of the 6.3- um pixel’s is seeing light from an area about 3 times larger (113 ÷ 40 = 2.8) than the pixels. The greater pixel population created by the denser pixel pitch has had the grain removed by the larger aperture size. This creates a digital image file that will make a large print with no grain. The downside is the image resolution is sacrificed in favor removing film grain. In the language of a flatbed scanner operator: the image has empty pixels. Not that there are clones of parent pixels, but that each pixel was made with an aperture that was 3 times larger than the size of the pixel; different process same concept.”


    My question is this. If your film has a resolution of 4000 dpi or higher (which would require an aperture of 6 um), don't you essentially throw away this resolution if you use an aperture of 13 um or higher? Even if you use a ppi pixel pitch of 4000, resolution is still only about 2000 ppi, so the scanner is just interpolating data points. Really no different than if you were rezzing up the image file in PS.

    Sandy
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

  6. #16

    Re: Compact drumscanner

    Actually I see it as different... the drum scanner, if set to a resolution higher than that aperture, is actually sampling at the higher rate. It's just that there is more wrap around from each sample, and more overlap from each sample, and that could be stating it badly... I see it more as the difference between a point source enlarger head vs a diffusion enlarger head. But the practical and visual differences between this and uprezzing can really only be determined by careful comparison tests. I've gone back and forth on this since day one of getting a drum scanner with a variable aperture.
    Tyler

  7. #17

    Re: Compact drumscanner

    actually, reading this, I'm uncertain of the explanation of how the samples are combined, a bit over my head on a holiday. Would be interesting to get Tim into this conversation, he's been very approachable in the past.
    Tyler

  8. #18

    Join Date
    Feb 2008
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    41

    Re: Compact drumscanner

    Quote Originally Posted by Tyler Boley View Post
    actually, reading this, I'm uncertain of the explanation of how the samples are combined, a bit over my head on a holiday. Would be interesting to get Tim into this conversation, he's been very approachable in the past.
    Tyler
    I'm online, what is it that needs to be added to the discussion?

    Tyler came and got me. I know Lenny and Sandy well.

    If you don't match the aperture to the resolution, you loose resolution. There may be a need for the extra pixels, but each one will be collected from an area larger than its footprint. Maybe you need the light; maybe you want to make a very large print; there are legitimate reasons.

    The quote Sandy gave is a little verbose, but I do not need to correct anything that was said.

    I think the issue of aperture size is quite critical because most people forget about it.

    The other issue is that many of the early drum scanners don't have the range of aperture options found in the more recent drum scanners.

    Cheers


    Tim
    510-594-8277

  9. #19

    Re: Compact drumscanner

    Hi Tim, I guess the question Sandy posed is of interest. What different might there be between creating more pixels by collecting more with the resolution of the scanner, or "making up" info by up-rezzing methods.
    And I don't mean interpolation by the scanner software, I mean higher res mechanical scanner settings, higher than the matched aperture setting... it seems to me it's real sampled information, not made up, even if not necessarily contributing detail.. actually the more I type the the less clear I am...
    TYler

  10. #20
    retrogrouchy
    Join Date
    Mar 2010
    Location
    Adelaide, Australia
    Posts
    832

    Re: Compact drumscanner

    Think of it as "stuff out of focus". You can sample that at higher resolution and not gain (much) more information with some very narrow exceptions.

    Think of the output image as being the input image convolved with the aperture - as the aperture gets bigger, the output gets softer. However if the aperture behaves like a perfect step function, then application of some postprocessing can deconvolve the softening effect to some degree and increase the resolution (not just the acutance) of the image. In the simplest case, an unsharp mask (with radius set to the aperture radius in pixels) applied to an image captured with a large scanner aperture, can restore some of the sharpness. Deconvolution is a messy and imprecise thing because there is some information loss in convolution, but the point is that capturing with a larger aperture does not automatically imply that you're just creating "empty pixels".

    Another term worth googling for is superresolution, but that applies only when there are multiple passes and there is jittering between the passes. The maths behind it is based on deconvolution though - you could think of a high-res soft image as being a regular array of slightly-offset lower-resolution images with larger pixels.

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