Questions About Minolta Dual III Scanner

Discussion in 'Minolta' started by narke, Mar 14, 2005.

  1. narke

    narke Guest


    When people talk about scanners, I heard them talk about 30bit or
    36bit? What this refer to? The bit width of A/D convertor? In the spec
    of Dual III, I found the A/D width is 16 bit, is it too low?

    And, people the maximized Dmax is 4.0 in theory, 3.8 is very very good
    in practice. However, in the spec of Dual III, I found the Dmax is
    4.8(computed), what this mean? What is the real Dmax value of Dual

    Thanks in advance.

    narke, Mar 14, 2005
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  2. narke

    Alan Browne Guest

    The more bits, the deeper the scanner sees into the dark area of the
    slide or negative (meaning better detail in shaddows on slides; better
    detail in the bright areas, highlights on negatives).

    When you see numbers like 36 bits, it means 12 bits per color (R,G,B),
    when yous see numbers like 16 bits, it means 16 bits per color or 48 total.

    Dmax (theory) = log (2^n) where n is the number of bits per color. The
    manufacturers seem to always quote this high number. In reality, 1.5
    bits can be tossed aside for noise, so log (2^14.5) = 4.36 is more
    realistic. As to the relationship with the 4.0 "max" Dmax, I'm not
    sure. (Google away, it's been pointed out to me in the past... I just
    don't remember...)

    Alan Browne, Mar 14, 2005
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  3. narke

    narke Guest

    Thank you Alan! Your explanation is very clear! Dmax or dynamic range
    is another side of a/d bit width.

    It seems the scan dual III is very higher is dynamic range. I heard
    LS30 is about 3.x
    narke, Mar 15, 2005
  4. narke

    Alan Browne Guest

    Yes. I didn't clarify that, but you interpreted the 1.5 correctly.
    The reality of scanner specs never matches the reality of scanning the
    film. Some scanners do miserably with some kinds of film. A Google
    groups search of will reveal a lot ... while
    giving you a headache too... Minolta and Nikon both make very good
    scanners. The latest Minolta (5400 II) looks great on paper and is very
    reasonably priced at B&H.

    Alan Browne, Mar 15, 2005
  5. narke

    Gordon Moat Guest

    Alan gave a good explanation of this. In general, more is better. Be aware
    that some scanners claim 16 bit, though it is only true of the resulting
    file, and not an indication of actual CCD and processor performance.
    Really a complicated issue, confounded by marketing, and further confused
    by barely any two manufacturers using the same measurements. Generally
    (again), the Dmax does not always indicate a usable range, unless Dmin is
    also stated. Often the high end of scanning gear can give a range of 3.7
    or better. In true high end professional gear (i.e. not available at Best
    Buy, CompUSA, or Office Depot), the value of 4.0 is used as a top figure,
    or highest possible range. While the technical explanation (theory) that
    Alan posted should be true, as he also indicated, it is often that in
    practice the claimed values are not reached. It would be fair to state
    that you should be sceptical of any claims greater than 4.0.

    My suggestion is to get the best scanner you can afford, and back it up
    with some good software. The Minolta is not a bad choice at all, judging
    by a couple I have seen in operation. Be aware that scanning is a skill
    driven by experience. Your scans might be good in default settings, but
    learn the intricacies of your chosen scanner, and then choosing your own
    settings will often improve results.

    Things to look for in a scanner include, manual focus, manual colour
    balance, some form of dust prevention (or easy cleaning), reasonable speed
    for work flow, settings that can be saved, and the ability to use other
    scanning software. I mention software since many scanners seem to have
    clunky, or poorly crafted, software. SilverFast is one choice, though many
    people don't like the pricing. Another choice is VueScan. A few scanners
    are supported by BinuScan, which seems to be a nice in between pricing

    Good luck!
    Gordon Moat, Mar 15, 2005
  6. narke

    narke Guest


    Thank you very much!
    narke, Mar 18, 2005
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